Re: Advantage of increased colour depth?
When you get to CS2 for printing, you'll want to use the settings I
described below for ColorSync managed printing and for Photoshop CS2
managed printing. They're what Adobe recommends for the two different
types of printing workflow, as distinguished from the working
colorspace and editing environment.
I use the "North American Prepress 2" set in Edit->Color Settings to
establish my editing environment and color management policies. My
RAW files are processed to a [EMAIL PROTECTED] RGB rendering with either
Adobe RGB or ProPhoto RGB color profile, when I edit a ProPhoto RGB
image, I tell CS2 to use the embedded profile, not to convert to
Adobe RGB. I do not convert profiles or downsample to 8bit per
channel prior to printing: I let CS2 do the color management and
downsampling through the settings used in "Print with Preview" and
the Epson print driver dialog.
CS2's color management is more sophisticated and the settings options
much clearer than CS was. I'm not entirely sure what your current
ColorSync workflow is actually doing, but that's not really very
important as long as it's producing the results you are happy with!
Godfrey
On Sep 8, 2006, at 7:33 AM, [EMAIL PROTECTED] wrote:
> I'm using CS1 at home, and I print only from that computer. As you
> guessed, that explains the disparity. My work laptop runs CS2, so I
> looked. Yes, the setup is different. I would think that choosing
> the working colorspace listed as "ColorSyncRGB-Generic RGB" in CS2
> would produce the same result. I'll eventually find out. I also
> took a look at Print with Preview in CS2. It offers different
> choices as well. I will have to experiment when I start using CS2
> to print. But I think the choice will either be "Let PhotoShop
> Determine Colors" or "No Color Management." I notice that if I
> choose "No Color Management* in CS2, the "Rendering Intent" menu
> goes grey, just as it does in CS1 when "Source" is set to Document.
>
> I realize my explanation was incomplete. I convert to Generic RGB
> colorspace and 8-bit mode before printing. In the print box, I
> choose Premium Luster or Velvet Fine Art, depending on which paper
> I'm using. For each of these I have saved my printer settings as
> Advanced, 28,800. (They're might be more, but I'm not on that
> computer now. ) I go to "Color Management" and make sure it's set
> to ColorSync Workflow. I'm printing on an Epson 2200 by the way,
> which can come very close to the 2400 in quality, although it's not
> as rugged or as good at ink management. My next printer will be a
> 2400, but I probably will wait until the 2200 gives up the ghost.
>
> I'm saving this thread and will experiment with your method when I
> upgrade to CS2. Thanks for all the info.
> Paul
> -- Original message --
> From: Godfrey DiGiorgi <[EMAIL PROTECTED]>
>> (Please: the term is "ColorSync", not "ColorSynch" ... it's an Apple
>> trademark.
>> There is no such thing as "ColorSynch". ;-)
>>
>> I'm sorry, i don't understand the description of your settings. There
>> is no option called "ColorSynch Workflow" in the Photoshop CS2 "Edit-
>>> Color Settings" dialog. There is an option for a working colorspace
>> listed as "ColorSync RGB - Generic RGB". Is that what you're using?
>>
>> I also don't see any settings as you've labeled in the Print with
>> Preview dialog ('Source', 'Print Space', etc). You don't list what
>> options you've set in the Epson print driver dialog.
>>
>> In the Photoshop CS2 help, when you search on ColorSync, it go to a
>> page describing "Letting the Printer Manage Color" and shows how to
>> set up a ColorSync printing workflow as I described below. I suspect
>> you're running Photoshop CS ...
>>
>> Godfrey
>>
>>
>> On Sep 8, 2006, at 3:31 AM, Paul Stenquist wrote:
>>
>>> No, the printer isn't managing color. Apple ColorSynch is
>>> handling it.
>>> In Photo Shop/Color Settings, the setting is at "Colorsynch
>>> Workflow."
>>> I n "Print to Preview, "Source" is set to "Document : Generic
>>> RGB." It
>>> stays that way. Don't have to change it. "Print Space" is set to
>>> "Same
>>> as Source." "Intent" is grayed out when you print with
>>> ColorSynch. In
>>> the print box. "Color Management" is set to ColorSynch. And of
>>> course
>>> the printer driver is chosen. Works beautifully.
>>> On Sep 7, 2006, at 12:15 PM, Godfrey DiGiorgi wrote:
>>>
I presume your ColorSync workflow runs like this:
- image in 16bit ProPhoto
- Print with Preview
- set "let printer manage color"
- set rendering intent
- epson driver
- set paper type and print resolution options
- set color management -> colorsync
So what happens is that Photoshop renders the data to the print
driver in 8bit form, having done an implicit conversion, and
then the
Epson driver renders the data with conversion for the pape
Re: Advantage of increased colour depth?
I'm using CS1 at home, and I print only from that computer. As you guessed,
that explains the disparity. My work laptop runs CS2, so I looked. Yes, the
setup is different. I would think that choosing the working colorspace listed
as "ColorSyncRGB-Generic RGB" in CS2 would produce the same result. I'll
eventually find out. I also took a look at Print with Preview in CS2. It offers
different choices as well. I will have to experiment when I start using CS2 to
print. But I think the choice will either be "Let PhotoShop Determine Colors"
or "No Color Management." I notice that if I choose "No Color Management* in
CS2, the "Rendering Intent" menu goes grey, just as it does in CS1 when
"Source" is set to Document.
I realize my explanation was incomplete. I convert to Generic RGB colorspace
and 8-bit mode before printing. In the print box, I choose Premium Luster or
Velvet Fine Art, depending on which paper I'm using. For each of these I have
saved my printer settings as Advanced, 28,800. (They're might be more, but I'm
not on that computer now. ) I go to "Color Management" and make sure it's set
to ColorSync Workflow. I'm printing on an Epson 2200 by the way, which can come
very close to the 2400 in quality, although it's not as rugged or as good at
ink management. My next printer will be a 2400, but I probably will wait until
the 2200 gives up the ghost.
I'm saving this thread and will experiment with your method when I upgrade to
CS2. Thanks for all the info.
Paul
-- Original message --
From: Godfrey DiGiorgi <[EMAIL PROTECTED]>
> (Please: the term is "ColorSync", not "ColorSynch" ... it's an Apple
> trademark.
> There is no such thing as "ColorSynch". ;-)
>
> I'm sorry, i don't understand the description of your settings. There
> is no option called "ColorSynch Workflow" in the Photoshop CS2 "Edit-
> >Color Settings" dialog. There is an option for a working colorspace
> listed as "ColorSync RGB - Generic RGB". Is that what you're using?
>
> I also don't see any settings as you've labeled in the Print with
> Preview dialog ('Source', 'Print Space', etc). You don't list what
> options you've set in the Epson print driver dialog.
>
> In the Photoshop CS2 help, when you search on ColorSync, it go to a
> page describing "Letting the Printer Manage Color" and shows how to
> set up a ColorSync printing workflow as I described below. I suspect
> you're running Photoshop CS ...
>
> Godfrey
>
>
> On Sep 8, 2006, at 3:31 AM, Paul Stenquist wrote:
>
> > No, the printer isn't managing color. Apple ColorSynch is handling it.
> > In Photo Shop/Color Settings, the setting is at "Colorsynch Workflow."
> > I n "Print to Preview, "Source" is set to "Document : Generic RGB." It
> > stays that way. Don't have to change it. "Print Space" is set to "Same
> > as Source." "Intent" is grayed out when you print with ColorSynch. In
> > the print box. "Color Management" is set to ColorSynch. And of course
> > the printer driver is chosen. Works beautifully.
> > On Sep 7, 2006, at 12:15 PM, Godfrey DiGiorgi wrote:
> >
> >> I presume your ColorSync workflow runs like this:
> >>
> >> - image in 16bit ProPhoto
> >> - Print with Preview
> >> - set "let printer manage color"
> >> - set rendering intent
> >> - epson driver
> >> - set paper type and print resolution options
> >> - set color management -> colorsync
> >>
> >> So what happens is that Photoshop renders the data to the print
> >> driver in 8bit form, having done an implicit conversion, and then the
> >> Epson driver renders the data with conversion for the paper type,
> >> inkset, and ColorSync profile.
> >>
> >> The results can be very good, and difficult to distinguish from the
> >> 'all photoshop' printing workflow ...
> >>
> >> - image in 16bit ProPhoto
> >> - Print with Preview
> >> - set "let photoshop manage color"
> >> - set paper/inkset/printer profile and rendering intent
> >> - epson driver
> >> - set paper type and print resolution options
> >> - set color management -> off
> >>
> >> The difference is when/where the conversion to 8bit happens relative
> >> to the profile conversion. In the latter workflow, the profile
> >> conversion happens before the 8bit conversion, in the ColorSync
> >> workflow the profile conversion happens later. Depending upon the
> >> paper type and the exact printer model you have, it might be
> >> difficult to demonstrate the difference. Also, the quality of the
> >> ColorSync profile for a given paper/inkset/printer is a factor.
> >>
> >> The R2400, K3 inkset, and supplied profiles for Epson Enhanced Matte
> >> and Epson Fine Art Velvet (my standard papers) are very very good,
> >> there have only been a couple of occasions where I found any reason
> >> to fine tune the printing process with the driver controls.
> >>
> >> Godfrey
> >>
> >> On Sep 7, 2006, at 3:23 AM, Paul Stenquist wrote:
> >>
> >>> I use ColorSynch for printing, s
Re: Advantage of increased colour depth?
(Please: the term is "ColorSync", not "ColorSynch" ... it's an Apple
trademark.
There is no such thing as "ColorSynch". ;-)
I'm sorry, i don't understand the description of your settings. There
is no option called "ColorSynch Workflow" in the Photoshop CS2 "Edit-
>Color Settings" dialog. There is an option for a working colorspace
listed as "ColorSync RGB - Generic RGB". Is that what you're using?
I also don't see any settings as you've labeled in the Print with
Preview dialog ('Source', 'Print Space', etc). You don't list what
options you've set in the Epson print driver dialog.
In the Photoshop CS2 help, when you search on ColorSync, it go to a
page describing "Letting the Printer Manage Color" and shows how to
set up a ColorSync printing workflow as I described below. I suspect
you're running Photoshop CS ...
Godfrey
On Sep 8, 2006, at 3:31 AM, Paul Stenquist wrote:
> No, the printer isn't managing color. Apple ColorSynch is handling it.
> In Photo Shop/Color Settings, the setting is at "Colorsynch Workflow."
> I n "Print to Preview, "Source" is set to "Document : Generic RGB." It
> stays that way. Don't have to change it. "Print Space" is set to "Same
> as Source." "Intent" is grayed out when you print with ColorSynch. In
> the print box. "Color Management" is set to ColorSynch. And of course
> the printer driver is chosen. Works beautifully.
> On Sep 7, 2006, at 12:15 PM, Godfrey DiGiorgi wrote:
>
>> I presume your ColorSync workflow runs like this:
>>
>> - image in 16bit ProPhoto
>> - Print with Preview
>> - set "let printer manage color"
>> - set rendering intent
>> - epson driver
>> - set paper type and print resolution options
>> - set color management -> colorsync
>>
>> So what happens is that Photoshop renders the data to the print
>> driver in 8bit form, having done an implicit conversion, and then the
>> Epson driver renders the data with conversion for the paper type,
>> inkset, and ColorSync profile.
>>
>> The results can be very good, and difficult to distinguish from the
>> 'all photoshop' printing workflow ...
>>
>> - image in 16bit ProPhoto
>> - Print with Preview
>> - set "let photoshop manage color"
>> - set paper/inkset/printer profile and rendering intent
>> - epson driver
>> - set paper type and print resolution options
>> - set color management -> off
>>
>> The difference is when/where the conversion to 8bit happens relative
>> to the profile conversion. In the latter workflow, the profile
>> conversion happens before the 8bit conversion, in the ColorSync
>> workflow the profile conversion happens later. Depending upon the
>> paper type and the exact printer model you have, it might be
>> difficult to demonstrate the difference. Also, the quality of the
>> ColorSync profile for a given paper/inkset/printer is a factor.
>>
>> The R2400, K3 inkset, and supplied profiles for Epson Enhanced Matte
>> and Epson Fine Art Velvet (my standard papers) are very very good,
>> there have only been a couple of occasions where I found any reason
>> to fine tune the printing process with the driver controls.
>>
>> Godfrey
>>
>> On Sep 7, 2006, at 3:23 AM, Paul Stenquist wrote:
>>
>>> I use ColorSynch for printing, so I'm not sure how this relates.
>>> I do
>>> all processing on a 16-bit file in Pro Photo Color Space, which is
>>> said
>>> to be an even wider gamut than Adobe 98. I save that original. If
>>> I'm
>>> going to print a file, I convert it to Generic RGB, then convert
>>> to 8
>>> bit,. I select the profile for my paper in the print box, turn on
>>> ColorSync management in the print box and hit the button. I'm
>>> printing
>>> on an Epson 2200. I get beautiful results this way. I'm not sure
>>> if I
>>> could do better some other way. But past experiments have always
>>> led me
>>> right back to this method.
>>
>>
>> --
>> PDML Pentax-Discuss Mail List
>> PDML@pdml.net
>> http://pdml.net/mailman/listinfo/pdml_pdml.net
>>
>
>
> --
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Re: Advantage of increased colour depth?
No, the printer isn't managing color. Apple ColorSynch is handling it. In Photo Shop/Color Settings, the setting is at "Colorsynch Workflow." I n "Print to Preview, "Source" is set to "Document : Generic RGB." It stays that way. Don't have to change it. "Print Space" is set to "Same as Source." "Intent" is grayed out when you print with ColorSynch. In the print box. "Color Management" is set to ColorSynch. And of course the printer driver is chosen. Works beautifully. On Sep 7, 2006, at 12:15 PM, Godfrey DiGiorgi wrote: > I presume your ColorSync workflow runs like this: > > - image in 16bit ProPhoto > - Print with Preview > - set "let printer manage color" > - set rendering intent > - epson driver > - set paper type and print resolution options > - set color management -> colorsync > > So what happens is that Photoshop renders the data to the print > driver in 8bit form, having done an implicit conversion, and then the > Epson driver renders the data with conversion for the paper type, > inkset, and ColorSync profile. > > The results can be very good, and difficult to distinguish from the > 'all photoshop' printing workflow ... > > - image in 16bit ProPhoto > - Print with Preview > - set "let photoshop manage color" > - set paper/inkset/printer profile and rendering intent > - epson driver > - set paper type and print resolution options > - set color management -> off > > The difference is when/where the conversion to 8bit happens relative > to the profile conversion. In the latter workflow, the profile > conversion happens before the 8bit conversion, in the ColorSync > workflow the profile conversion happens later. Depending upon the > paper type and the exact printer model you have, it might be > difficult to demonstrate the difference. Also, the quality of the > ColorSync profile for a given paper/inkset/printer is a factor. > > The R2400, K3 inkset, and supplied profiles for Epson Enhanced Matte > and Epson Fine Art Velvet (my standard papers) are very very good, > there have only been a couple of occasions where I found any reason > to fine tune the printing process with the driver controls. > > Godfrey > > On Sep 7, 2006, at 3:23 AM, Paul Stenquist wrote: > >> I use ColorSynch for printing, so I'm not sure how this relates. I do >> all processing on a 16-bit file in Pro Photo Color Space, which is >> said >> to be an even wider gamut than Adobe 98. I save that original. If I'm >> going to print a file, I convert it to Generic RGB, then convert to 8 >> bit,. I select the profile for my paper in the print box, turn on >> ColorSync management in the print box and hit the button. I'm printing >> on an Epson 2200. I get beautiful results this way. I'm not sure if I >> could do better some other way. But past experiments have always >> led me >> right back to this method. > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
On Sep 8, 2006, at 8:21 PM, Jostein Øksne wrote: > Same here. > In addition, I have had profiles made for my printer/paper > combination, and tell Photoshop to use those profiles. Very well spent > money, since I don't have to think each time I print...:-) A friend of mine paid for some profiles as well. Not so long ago we did a comparison using some portraits he'd taken. I'm still using the Epson profiles: the "higher quality" versions from their website. His version did look a little more pleasing to my eye, but his profiles had a tendency to saturate the whites a little bit earlier. If I'd adjusted the white/black points appropriately then the differences may have been a bit more subtle... but he'd asked me to just load the file and print as-is :) Either way I certainly wasn't disappointed with my result. My landscape photos still come out pretty well, although lately the subject matter hasn't been so hot (I have to run a print once a week, whether I want to or not, to prevent clogs). - Dave -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
On 9/8/06, David Mann <[EMAIL PROTECTED]> wrote: >> The method I use is pretty much the opposite of yours: I do the > colour management in the Photoshop "Print with preview" dialog, and > switch off colour management in the printer driver. Still works OK :) Same here. In addition, I have had profiles made for my printer/paper combination, and tell Photoshop to use those profiles. Very well spent money, since I don't have to think each time I print...:-) Jostein -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
At 02:26 PM 8/09/2006, David Mann wrote: >The method I use is pretty much the opposite of yours: I do the >colour management in the Photoshop "Print with preview" dialog, and >switch off colour management in the printer driver. Still works OK :) Same here. Dave -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
On Sep 7, 2006, at 10:23 PM, Paul Stenquist wrote: > I do all processing on a 16-bit file in Pro Photo Color Space, > which is said > to be an even wider gamut than Adobe 98. ProPhoto RGB is much, much wider than Adobe 1998. I'm glad you're using 16-bit files as 8-bit could be prone to posterisation. > I save that original. If I'm > going to print a file, I convert it to Generic RGB, then convert to 8 > bit,. I select the profile for my paper in the print box, turn on > Colorsynch management in the print box and hit the button. FWIW I'd skip the colour space conversion if I were you. If you're worried about exceeding the ink/paper gamut, you can use the gamut warning in Photoshop (you'll need to set up the soft-proofing settings first). Note that the Generic RGB profile is actually quite small (its gamut is almost identical to that of sRGB). The method I use is pretty much the opposite of yours: I do the colour management in the Photoshop "Print with preview" dialog, and switch off colour management in the printer driver. Still works OK :) - Dave -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
I presume your ColorSync workflow runs like this: - image in 16bit ProPhoto - Print with Preview - set "let printer manage color" - set rendering intent - epson driver - set paper type and print resolution options - set color management -> colorsync So what happens is that Photoshop renders the data to the print driver in 8bit form, having done an implicit conversion, and then the Epson driver renders the data with conversion for the paper type, inkset, and ColorSync profile. The results can be very good, and difficult to distinguish from the 'all photoshop' printing workflow ... - image in 16bit ProPhoto - Print with Preview - set "let photoshop manage color" - set paper/inkset/printer profile and rendering intent - epson driver - set paper type and print resolution options - set color management -> off The difference is when/where the conversion to 8bit happens relative to the profile conversion. In the latter workflow, the profile conversion happens before the 8bit conversion, in the ColorSync workflow the profile conversion happens later. Depending upon the paper type and the exact printer model you have, it might be difficult to demonstrate the difference. Also, the quality of the ColorSync profile for a given paper/inkset/printer is a factor. The R2400, K3 inkset, and supplied profiles for Epson Enhanced Matte and Epson Fine Art Velvet (my standard papers) are very very good, there have only been a couple of occasions where I found any reason to fine tune the printing process with the driver controls. Godfrey On Sep 7, 2006, at 3:23 AM, Paul Stenquist wrote: > I use ColorSynch for printing, so I'm not sure how this relates. I do > all processing on a 16-bit file in Pro Photo Color Space, which is > said > to be an even wider gamut than Adobe 98. I save that original. If I'm > going to print a file, I convert it to Generic RGB, then convert to 8 > bit,. I select the profile for my paper in the print box, turn on > ColorSync management in the print box and hit the button. I'm printing > on an Epson 2200. I get beautiful results this way. I'm not sure if I > could do better some other way. But past experiments have always > led me > right back to this method. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
On 07/09/06, Paul Stenquist <[EMAIL PROTECTED]> wrote: > I use ColorSynch for printing, so I'm not sure how this relates. I do > all processing on a 16-bit file in Pro Photo Color Space, which is said > to be an even wider gamut than Adobe 98. ProPhoto RGB color space is very wide (~290k cubic colorspace units), to the point where working in 8 bits can definitely be problematic, Adobe RGB is just a little larger (~131k cubic colorspace units) in some areas than sRGB (the standard monitor color space, ~90k cubic colorspace units) Incidentally and further off the track analysing my monitor calibration profiles it appears that my CRT profile covers ~104k colorspace units and my TFT display covers ~89k colorspace units. http://www.iccview.de/index_eng.htm -- Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://home.swiftdsl.com.au/~distudio//publications/ Pentax user since 1986, PDMLer since 1998 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
I use ColorSynch for printing, so I'm not sure how this relates. I do all processing on a 16-bit file in Pro Photo Color Space, which is said to be an even wider gamut than Adobe 98. I save that original. If I'm going to print a file, I convert it to Generic RGB, then convert to 8 bit,. I select the profile for my paper in the print box, turn on Colorsynch management in the print box and hit the button. I'm printing on an Epson 2200. I get beautiful results this way. I'm not sure if I could do better some other way. But past experiments have always led me right back to this method. Paul On Sep 6, 2006, at 11:53 PM, Godfrey DiGiorgi wrote: > I always do profile conversions in 16bit. You can see the histograms > jump more when you go to 8bit. > > If you tell Photoshop to let the printer do the color management, the > image data is reduced to 8bit on the way to the print driver *before* > profile conversion, meaning more shifts will be apparent. When > Photoshop is managing the process, it converts to 8bit as the final > step before sending to the driver, which is in pass through mode. > > Godfrey > > On Sep 6, 2006, at 3:35 PM, Paul Stenquist wrote: > >> I doubt that any is from the bit depth, unless Godfrey is emphasizing >> the importance of starting with a 16-bit file and doing all the >> processing in 16 bit. Whether PhotoShop converts to 8-bit before >> printing or while printing would seem to make no difference. >> Obviously, color space can make a difference with many images. >> Starting with a 16-bit file is important, but at some point PhotoShop >> has to convert. > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
I always do profile conversions in 16bit. You can see the histograms jump more when you go to 8bit. If you tell Photoshop to let the printer do the color management, the image data is reduced to 8bit on the way to the print driver *before* profile conversion, meaning more shifts will be apparent. When Photoshop is managing the process, it converts to 8bit as the final step before sending to the driver, which is in pass through mode. Godfrey On Sep 6, 2006, at 3:35 PM, Paul Stenquist wrote: > I doubt that any is from the bit depth, unless Godfrey is emphasizing > the importance of starting with a 16-bit file and doing all the > processing in 16 bit. Whether PhotoShop converts to 8-bit before > printing or while printing would seem to make no difference. > Obviously, color space can make a difference with many images. > Starting with a 16-bit file is important, but at some point PhotoShop > has to convert. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
As Rob said, they are interdependent. Photoshop has to convert the 16bit aRGB image data to the scanner/paper profile (via the appropriate rendering intent, etc) I've selected and then to 8bit to drive the scanner. The possibility of a lot of round off error is minimized by using 16bit files. The print driver isn't quite as sophisticated about the conversions, and you can see the difference. Godfrey On Sep 6, 2006, at 1:20 PM, Rick Womer wrote: > Godfrey, > > How much of that difference is from the broader color > space, and how much from the bit depth? > >> I see printing differences in the photographs I make >> that are >> optimized with Adobe RGB (1998) colorspace and >> [EMAIL PROTECTED], printed >> to the R2400, compared to the same photograph >> optimized for sRGB >> colorspace and [EMAIL PROTECTED] The aRGB/16 prints are >> invariably better >> than the sRGB/8 prints. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
On 07/09/06, Rick Womer <[EMAIL PROTECTED]> wrote: > Godfrey, > > How much of that difference is from the broader color > space, and how much from the bit depth? Both are interlinked, if you implement a very wide color space at low bit rates you may run the risk of having to steps which are too course and which may lead to visible degradation particularly after implementing curve transforms. -- Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://home.swiftdsl.com.au/~distudio//publications/ Pentax user since 1986, PDMLer since 1998 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
On 07/09/06, Dario Bonazza <[EMAIL PROTECTED]> wrote: > I understand that all this 22-bit A/D stuff - whichevet its tue implications > on wider dynamic range vs. subtler nuances, both or neither - will affect > also RAW files, not just JPEG's. > > Correct? Fortunately no if the they utilize a product such as that from Nucore. The 22 ADC is the sole device to sample the sensor data, after that the 22bit data stream (still independent R-G-B-G Bayer channels) may undergo gamma remapping. The signal can then be demosaiced or saved as RAW (or both in the case of the K10D) using further processors. -- Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://home.swiftdsl.com.au/~distudio//publications/ Pentax user since 1986, PDMLer since 1998 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
I doubt that any is from the bit depth, unless Godfrey is emphasizing the importance of starting with a 16-bit file and doing all the processing in 16 bit. Whether PhotoShop converts to 8-bit before printing or while printing would seem to make no difference. Obviously, color space can make a difference with many images. Starting with a 16-bit file is important, but at some point PhotoShop has to convert. Paul On Sep 6, 2006, at 4:20 PM, Rick Womer wrote: > Godfrey, > > How much of that difference is from the broader color > space, and how much from the bit depth? > > Rick > > --- Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: > >> >> I see printing differences in the photographs I make >> that are >> optimized with Adobe RGB (1998) colorspace and >> [EMAIL PROTECTED], printed >> to the R2400, compared to the same photograph >> optimized for sRGB >> colorspace and [EMAIL PROTECTED] The aRGB/16 prints are >> invariably better >> than the sRGB/8 prints. >> >> Godfrey >> >> >> On Sep 6, 2006, at 12:22 PM, Rick Womer wrote: >> >>> All of this is very nice, but where is a computer >>> monitor or print that can take advantage of these >>> capabilities? Regardless of the camera's >>> capabilities, it seems to be an 8-bit world when >> it >>> comes to viewing the photo. >> >> >> -- >> PDML Pentax-Discuss Mail List >> PDML@pdml.net >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> > > > http://www.photo.net/photos/RickW > > __ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
I understand that all this 22-bit A/D stuff - whichevet its tue implications on wider dynamic range vs. subtler nuances, both or neither - will affect also RAW files, not just JPEG's. Correct? Thanks, Dario -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
> Does the increased bit depth actually equate to more dynamic range or is > it > the same dynamic range graduated into smaller increments? More importantly will it produce a "better printed image"? Kenneth Waller - Original Message - From: "Tom C" <[EMAIL PROTECTED]> Subject: Re: Advantage of increased colour depth? > So what is the upshot of all this? I haven't followed every post over the > 3-day weekend. > > Does the increased bit depth actually equate to more dynamic range or is > it > the same dynamic range graduated into smaller increments? > > > > Tom C. > > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
RE: Advantage of increased colour depth?
I am afraid you are right. But as far as I know, we don't have knowledge of what dynamic range the sensor is capable of. So there could be potential for dynamic improvement here. I have also been thinking about what use of high pass filters beyond our hearing limit can do in a sound system. The point is that what looks like overkill, can make a difference. I don't know how relevant this is. Most likely it has no relevance at all ;-) I've also been speculating about more accurate information concerning colours. This could give room for a better noise removing system. But this is unqualified speculations. So personally I think I'll just have to settle with waiting for the camera hitting the shelves. Tim Mostly harmless (just plain Norwegian) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom C Sent: 6. september 2006 22:13 To: pdml@pdml.net Subject: RE: Advantage of increased colour depth? While I have a rudimentary understanding of such things, it would seem that the sensor itself, being the source of the image data is the most critical component in determining the dynamic range of the recorded image. Given, as I seem to recall, that other mfrs. may use the same sensor, I don't understand how the overall dynamic range can be any better using a different A/D convertor. The entire image may be more finely graduated, but that would not extend the top or bottom limit of the range. Whether this finer gradation is visible to the casual untrained human eye is yet to be seen. At least that's the simplistic view I have of the matter. Tom C. >From: Tim Øsleby <[EMAIL PROTECTED]> >Reply-To: Pentax-Discuss Mail List >To: "'Pentax-Discuss Mail List'" >Subject: RE: Advantage of increased colour depth? >Date: Wed, 6 Sep 2006 21:18:54 +0200 > >Don't think you would have found an answer reading the tread. Some hope for >better dynamic range, some says it will improve the colour nuances, and >some >say a little bit of both. As usual it is speculations, some qualified >speculations, but still speculation. > >Personally I hope for a little bit of both. > >We might get some real information in the days after sept. 14. > > >Tim >Mostly harmless (just plain Norwegian) > > >-Original Message- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom >C >Sent: 6. september 2006 21:11 >To: pdml@pdml.net >Subject: Re: Advantage of increased colour depth? > >So what is the upshot of all this? I haven't followed every post over the >3-day weekend. > >Does the increased bit depth actually equate to more dynamic range or is it >the same dynamic range graduated into smaller increments? > > > >Tom C. > > > >-- >PDML Pentax-Discuss Mail List >PDML@pdml.net >http://pdml.net/mailman/listinfo/pdml_pdml.net > > > > > >-- >PDML Pentax-Discuss Mail List >PDML@pdml.net >http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
Godfrey, How much of that difference is from the broader color space, and how much from the bit depth? Rick --- Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: > > I see printing differences in the photographs I make > that are > optimized with Adobe RGB (1998) colorspace and > [EMAIL PROTECTED], printed > to the R2400, compared to the same photograph > optimized for sRGB > colorspace and [EMAIL PROTECTED] The aRGB/16 prints are > invariably better > than the sRGB/8 prints. > > Godfrey > > > On Sep 6, 2006, at 12:22 PM, Rick Womer wrote: > > > All of this is very nice, but where is a computer > > monitor or print that can take advantage of these > > capabilities? Regardless of the camera's > > capabilities, it seems to be an 8-bit world when > it > > comes to viewing the photo. > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > http://www.photo.net/photos/RickW __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
RE: Advantage of increased colour depth?
While I have a rudimentary understanding of such things, it would seem that the sensor itself, being the source of the image data is the most critical component in determining the dynamic range of the recorded image. Given, as I seem to recall, that other mfrs. may use the same sensor, I don't understand how the overall dynamic range can be any better using a different A/D convertor. The entire image may be more finely graduated, but that would not extend the top or bottom limit of the range. Whether this finer gradation is visible to the casual untrained human eye is yet to be seen. At least that's the simplistic view I have of the matter. Tom C. From: Tim Øsleby <[EMAIL PROTECTED]> Reply-To: Pentax-Discuss Mail List To: "'Pentax-Discuss Mail List'" Subject: RE: Advantage of increased colour depth? Date: Wed, 6 Sep 2006 21:18:54 +0200 Don't think you would have found an answer reading the tread. Some hope for better dynamic range, some says it will improve the colour nuances, and some say a little bit of both. As usual it is speculations, some qualified speculations, but still speculation. Personally I hope for a little bit of both. We might get some real information in the days after sept. 14. Tim Mostly harmless (just plain Norwegian) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom C Sent: 6. september 2006 21:11 To: pdml@pdml.net Subject: Re: Advantage of increased colour depth? So what is the upshot of all this? I haven't followed every post over the 3-day weekend. Does the increased bit depth actually equate to more dynamic range or is it the same dynamic range graduated into smaller increments? Tom C. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
High end, calibrated computer monitors reveal a remarkable amount of nuance with good image display software and color management, but nuances are visible in a print, assuming a color managed workflow and a quality printer, that are not visible on a computer screen. Round- off errors accumulate in all the transformations being done to print an image. I let Photoshop manage the print process directly from full resolution PSD files, bypassing the driver's 16->8bit conversion and color management. I see printing differences in the photographs I make that are optimized with Adobe RGB (1998) colorspace and [EMAIL PROTECTED], printed to the R2400, compared to the same photograph optimized for sRGB colorspace and [EMAIL PROTECTED] The aRGB/16 prints are invariably better than the sRGB/8 prints. Godfrey On Sep 6, 2006, at 12:22 PM, Rick Womer wrote: > All of this is very nice, but where is a computer > monitor or print that can take advantage of these > capabilities? Regardless of the camera's > capabilities, it seems to be an 8-bit world when it > comes to viewing the photo. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
Folks,
All of this is very nice, but where is a computer
monitor or print that can take advantage of these
capabilities? Regardless of the camera's
capabilities, it seems to be an 8-bit world when it
comes to viewing the photo.
Rick
--- Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote:
> It's difficult to estimate how much advantage there
> is to having 16
> bits of quantization space vs 12 bits without more
> data, with respect
> to total dynamic range in stops or EV numbers.
>
> The analog capture range of the sensor from
> saturation input to noise
> threshold ("how much energy will max a photosite
> voltage rise to how
> little energy will trigger a photosite voltage
> rise") is one measure
> you have to know. You also have to take into account
> the typical
> gamma curve used to transform the linear capture
> space of the sensor
> to a rendered RGB image. The gamma curve compresses
> together the high
> values and spaces apart the low values to fit the
> captured data to
> the appropriate brightness range required for human
> vision. You also
> need a measure for 'acceptable noise' at the black
> point clipping
> level. Let's presume this latter is a constant,
> whatever it is.
>
> With todays 12bit sensors, quantization depth would
> net 12 stops
> tonal capture theoretically, but post-gamma
> correction the resulting
> output is in the range of 7-9 stops maximum, given
> the analog dynamic
> range limits of the sensor.
>
> If the K10D sensor has the same analog range of
> sensitivity as the
> current 6Mpixel sensor and 16 bit quantization space
> instead of the
> current 12 bit, what this means is that it can
> distinguish 16x more
> tonal steps in the analog range of its linear
> capture space.
> Processing this input with a 22bit image processing
> engine poses an
> advantage in reduced round-off error and accurate
> representation of
> the captured data into final storage form. If the
> analog dynamic
> range of the sensor is the same, it will still have
> the same 7 to 9
> stops of dynamic range, but they will be more
> accurately represented.
>
> That's as much as we can say without knowing the
> analog dynamic range
> of the sensor in question. Medium format backs with
> 16bit sensors
> typically have additional analog dynamic range in
> addition to larger
> quantization space, netting an increase in output
> dynamic range up to
> the 12 stop range with more accurate representation
> of tonal values
> captured ... there's a reason these MF sensors are
> expensive both in
> price as well as space and power requirements.
>
> BTW: 12 stops of analog dynamic range surpasses any
> film I've ever used.
>
> Godfrey
>
>
> On Sep 6, 2006, at 12:52 AM, Jostein Øksne wrote:
>
> > With all the talk of a 22 bit A/D converter for
> the K10D, and the
> > corresponding speculations of true 16-bit colour
> depth in the
> > raw-files, there are a couple of things I wonder
> about.
> >
> > Firstly, I wondered what the competition was
> doing. In the 35mm realm,
> > Canon use 12-bit colour depth in both 5D and
> 1DSmkII. I didn't check
> > other models. Leica, however, use 16-bit for the
> R-series digital
> > back. In the medium format realm, it seems that
> all the makers except
> > Mamiya use 16-bit. I have checked Sinar, Leaf,
> PhaseOne and Imacon.
> > Mamiya ZD use 12-bit colour depth, but 14-bit A/D.
> I couldn't find any
> > info on the A/D conversion for the other brands.
> >
> > Anyway, it seems that 12-bit is a standard for
> 35mm, and that 16-bit
> > colour rule the medium format world.
> >
> > Better dynamic range has been mentioned frequently
> in the discussion
> > of 16-bit colour, but I don't think I paid enough
> attention. How much
> > would 16-bit depth improve the dynamic range over
> 12-bit in terms of
> > f-stops? Is this going to be like going from slide
> film to colour
> > negatives, or is this on a different scale?
> >
> >
> > thanks,
> >
> > Jostein
> >
> > --
> > PDML Pentax-Discuss Mail List
> > PDML@pdml.net
> > http://pdml.net/mailman/listinfo/pdml_pdml.net
>
>
> --
> PDML Pentax-Discuss Mail List
> PDML@pdml.net
> http://pdml.net/mailman/listinfo/pdml_pdml.net
>
http://www.photo.net/photos/RickW
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RE: Advantage of increased colour depth?
Don't think you would have found an answer reading the tread. Some hope for better dynamic range, some says it will improve the colour nuances, and some say a little bit of both. As usual it is speculations, some qualified speculations, but still speculation. Personally I hope for a little bit of both. We might get some real information in the days after sept. 14. Tim Mostly harmless (just plain Norwegian) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom C Sent: 6. september 2006 21:11 To: pdml@pdml.net Subject: Re: Advantage of increased colour depth? So what is the upshot of all this? I haven't followed every post over the 3-day weekend. Does the increased bit depth actually equate to more dynamic range or is it the same dynamic range graduated into smaller increments? Tom C. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
So what is the upshot of all this? I haven't followed every post over the 3-day weekend. Does the increased bit depth actually equate to more dynamic range or is it the same dynamic range graduated into smaller increments? Tom C. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
Maybe we can somewhat comapre this with a tech introduced a couple years ago by Sony dubbed SBM (SuperBitMapping) which was used on the process of mastering an audio cd. As you know an audio cd is encoded with a 16bit depth. But Sony with SBM forst did master the source to 20bit (oversampling?) to later downsample it to 16bit before putting it on the audio cd. Thibault Massart aka Thibouille -- *ist-D,Z1,SuperA,KX,MX, P30t and KR-10x ;) ... -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
On Wed, Sep 06, 2006 at 01:22:43PM +0200, Toralf Lund wrote: > > According to sources on the Net, the current 6MP sensors have a range > corresponding to slightly more than 6 "steps", or somewhat less that > the full range of 16 bits. However, the full range is not really usable > due to noise; noise essentially means that the output for the same > exposure level may vary between several steps next to each other. > Apparently, the noise in the sensors used up to now will typically > correspond to 10 levels or so, equivalent to 3 or 4 bits. In other > words, if you were to use 16 bits, the lower 4 would probably contain > little more than random data caused by the noise. This means you are > left with a usable range corresponding to 12 bits. > > With a 10MP sensor of the same size, the number of levels should be > reduced to something like 35000, meaning that the range even before you > consider the noise is closer to 15 bits than 16. It gets a bit worse than that. The sensitivity (or range) is proportional to the area of the sensor site, all other things (ISO, sensor materials, etc.) being kept the same. But the noise doesn't increase linearly with area; because the noise is effectively the sum of several independent contributions the total noise level increases with the square root of the area. Or, to put it another way, when you decrease the size of the sensor not only does the total sensor range decrease - the drop in the noise is smaller than the drop in the signal, so the signal-to-noise ratio also decreases. That means that if you had, say, a 16-bit sensor with four bits of noise (giving you 12 bits of signal) then the same technology with the smaller sensor sites would give a 15-bit sensor with 3.5 bits of noise, or only 11.5 bits of signal. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
>>> >> It's been mentioned before, but based on some info Rob Studdert dug up, >> I'm lead to believe that there aren't any extra tricks involved in those >> 22bits. It's probably all about a circuit designed to work with >> different types of sensors, that *for internal use* converts the signal >> from the sensor to a digital value with so many bits that you can be >> pretty sure no information (not even the noise) is lost, no matter what >> sensor you throw at it - and probably also so that calculations that >> involve multiple steps won't loose accuracy between the steps [ ... ] >> > > Somebody mentioned the use of curves to increase the nice parts of the signal > and reduce the noisy part. That could be done with the 22bit conversion, but > this is speculation. I often use curves that way in 16bit TIFF before I > reduce it to 8bit jpeg. > Yes, now that you mention it, the info posted by Rob also suggested that there would be a gamma correction/"curves" stage internally - also working with 22 bits, obviously. If you do that kind of thing, you'll loose accuracy even in the output data unless you include some extra bits. Basically, these are needed in order to encode the fact that the output from the curves adjustment might fall between two values in the input range, i.e. you may think of the extra bits as representing decimals. Introducing them won't really increase the dynamic range, though, since the adjustment will leave gaps larger than 1 input step at other spots. 22 bits in the final output is probably still pointless, but it has been suggested that you might get 14 or 16. - Toralf -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
Well, theoretically, you have one channel each of red, blue, green, and luminance (they use a green channel for luminance because it most closely matches the human eye). So yes you get more accurate color information, but also more dynamic range. In the real world you never seem to get that theoretical gain, but I would expect about 2 stops improvement (rather than the 4 stops theoretical). -- graywolf http://www.graywolfphoto.com http://webpages.charter.net/graywolf "Idiot Proof" <==> "Expert Proof" --- mike wilson wrote: >> From: "Jostein Øksne" <[EMAIL PROTECTED]> > >> Better dynamic range has been mentioned frequently in the discussion >> of 16-bit colour, but I don't think I paid enough attention. How much >> would 16-bit depth improve the dynamic range over 12-bit in terms of >> f-stops? Is this going to be like going from slide film to colour >> negatives, or is this on a different scale? >> > > I must admit that I haven't been paying too much attention to this matter but > I assumed that the meaning was in relation to colour only and not to > exposure. Just poor use of language - on someone's part 8-) Does greater > colour depth increase the range or merely the number of subdivisions of a > colour? > > m > > > - > Email sent from www.ntlworld.com > Virus-checked using McAfee(R) Software > Visit www.ntlworld.com/security for more information > > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
It's difficult to estimate how much advantage there is to having 16
bits of quantization space vs 12 bits without more data, with respect
to total dynamic range in stops or EV numbers.
The analog capture range of the sensor from saturation input to noise
threshold ("how much energy will max a photosite voltage rise to how
little energy will trigger a photosite voltage rise") is one measure
you have to know. You also have to take into account the typical
gamma curve used to transform the linear capture space of the sensor
to a rendered RGB image. The gamma curve compresses together the high
values and spaces apart the low values to fit the captured data to
the appropriate brightness range required for human vision. You also
need a measure for 'acceptable noise' at the black point clipping
level. Let's presume this latter is a constant, whatever it is.
With todays 12bit sensors, quantization depth would net 12 stops
tonal capture theoretically, but post-gamma correction the resulting
output is in the range of 7-9 stops maximum, given the analog dynamic
range limits of the sensor.
If the K10D sensor has the same analog range of sensitivity as the
current 6Mpixel sensor and 16 bit quantization space instead of the
current 12 bit, what this means is that it can distinguish 16x more
tonal steps in the analog range of its linear capture space.
Processing this input with a 22bit image processing engine poses an
advantage in reduced round-off error and accurate representation of
the captured data into final storage form. If the analog dynamic
range of the sensor is the same, it will still have the same 7 to 9
stops of dynamic range, but they will be more accurately represented.
That's as much as we can say without knowing the analog dynamic range
of the sensor in question. Medium format backs with 16bit sensors
typically have additional analog dynamic range in addition to larger
quantization space, netting an increase in output dynamic range up to
the 12 stop range with more accurate representation of tonal values
captured ... there's a reason these MF sensors are expensive both in
price as well as space and power requirements.
BTW: 12 stops of analog dynamic range surpasses any film I've ever used.
Godfrey
On Sep 6, 2006, at 12:52 AM, Jostein Øksne wrote:
> With all the talk of a 22 bit A/D converter for the K10D, and the
> corresponding speculations of true 16-bit colour depth in the
> raw-files, there are a couple of things I wonder about.
>
> Firstly, I wondered what the competition was doing. In the 35mm realm,
> Canon use 12-bit colour depth in both 5D and 1DSmkII. I didn't check
> other models. Leica, however, use 16-bit for the R-series digital
> back. In the medium format realm, it seems that all the makers except
> Mamiya use 16-bit. I have checked Sinar, Leaf, PhaseOne and Imacon.
> Mamiya ZD use 12-bit colour depth, but 14-bit A/D. I couldn't find any
> info on the A/D conversion for the other brands.
>
> Anyway, it seems that 12-bit is a standard for 35mm, and that 16-bit
> colour rule the medium format world.
>
> Better dynamic range has been mentioned frequently in the discussion
> of 16-bit colour, but I don't think I paid enough attention. How much
> would 16-bit depth improve the dynamic range over 12-bit in terms of
> f-stops? Is this going to be like going from slide film to colour
> negatives, or is this on a different scale?
>
>
> thanks,
>
> Jostein
>
> --
> PDML Pentax-Discuss Mail List
> PDML@pdml.net
> http://pdml.net/mailman/listinfo/pdml_pdml.net
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Re: Advantage of increased colour depth?
On Wed, 6 Sep 2006, DagT wrote: > In theory I think you could gain 4 stops. One stop is x2 more light, so x2^4 > should translate to 4 stops. > ... and the lowest 4 stops would be nothing but noise unless the physics of the sensor have improved. That's the reason why 12 or 14 bits is all that has been done so far... no point in using 16 or 22 bits for a device that has 0dB SNR by the 12th bit anyway. -Cory -- * * Cory Papenfuss, Ph.D., PPSEL-IA * * Electrical Engineering* * Virginia Polytechnic Institute and State University * * -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
DagT wrote: > Anyway, larger pixels will give an advantage in the range between noise > and saturation, so maybe in 645D... Yes, I'm convinced this 22-bit stuff is an obvious fall-out of the development of the 645D. After all, Pentax has always developed their 645 cameras from their hi-tech 35mm cameras of that same era (Super A -> 645 and MZ-5/MZ-S -> 645n/nII). Even the 67 derived from ES technology. This time, it appears to be an even stricter joint development, having already in mind what a medium format DSLR needs while designing the K10. I wonder if we'll truly see SR on the 645D. Why not? Dario -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
> Fra: Toralf Lund <[EMAIL PROTECTED]> > > > > Yes, you have to distribute your bits between the noise level and the > > saturation level. Some things, like an > >increase in the light sensitive area of each pixel or other tricks like > >reducing dark current, can suppress noise > >in one ends and other tricks like Fuji does with their sensors may give > >something in the other end. > Wouldn't an increase in the light sensitive area essentially mean > increasing the native ISO? I mean, the absolute noise and even noise > relative to saturation level would be the same, but saturation would be > reached faster. I'm not sure how close those two follow each other, but you may be right. I think Fuji uses a smaller pixel to measure the highlights, which means that it does not reach saturation as fast as the larger pixels. Other things may be done, at least in theory, like increasing the drain from the overexposed pixel to avoid saturation, or making the drain nonlinear. > > In addition you can gain a little bit in how you distribute your bits, > > and maybe that is what they do in the 22bit > >conversion. > > > It's been mentioned before, but based on some info Rob Studdert dug up, > I'm lead to believe that there aren't any extra tricks involved in those > 22bits. It's probably all about a circuit designed to work with > different types of sensors, that *for internal use* converts the signal > from the sensor to a digital value with so many bits that you can be > pretty sure no information (not even the noise) is lost, no matter what > sensor you throw at it - and probably also so that calculations that > involve multiple steps won't loose accuracy between the steps (think of > what happens if you do a division followed by a multiplication on a > digital value.) It will do various types of gain/offset adjustments in > this domain rather than on the analogue signal so as to make sure no > *extra* noise is introduced (the original noise may still be amplified, > of course.) Somebody mentioned the use of curves to increase the nice parts of the signal and reduce the noisy part. That could be done with the 22bit conversion, but this is speculation. I often use curves that way in 16bit TIFF before I reduce it to 8bit jpeg. DagT -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
>> >> Nice in theory anyway Of course, in the real world the linearity comes >> in to play as you say, but, as discussed previously, theres a point where >> sensor noise makes more bits basically meaningless. >> > > Yes, you have to distribute your bits between the noise level and the > saturation level. Some things, like an increase in the light sensitive area > of each pixel or other tricks like reducing dark current, can suppress noise > in one ends and other tricks like Fuji does with their sensors may give > something in the other end. Wouldn't an increase in the light sensitive area essentially mean increasing the native ISO? I mean, the absolute noise and even noise relative to saturation level would be the same, but saturation would be reached faster. > In addition you can gain a little bit in how you distribute your bits, and > maybe that is what they do in the 22bit conversion. > It's been mentioned before, but based on some info Rob Studdert dug up, I'm lead to believe that there aren't any extra tricks involved in those 22bits. It's probably all about a circuit designed to work with different types of sensors, that *for internal use* converts the signal from the sensor to a digital value with so many bits that you can be pretty sure no information (not even the noise) is lost, no matter what sensor you throw at it - and probably also so that calculations that involve multiple steps won't loose accuracy between the steps (think of what happens if you do a division followed by a multiplication on a digital value.) It will do various types of gain/offset adjustments in this domain rather than on the analogue signal so as to make sure no *extra* noise is introduced (the original noise may still be amplified, of course.) - Toralf -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
> >> In theory I think you could gain 4 stops. One stop is x2 more light, so x2^4 >> should translate to 4 stops. >> > > That's quite a lot. I don't find the raw files from *istD to lack much > in dynamic range as it is, so an increase of just 2 stops would > probably make me a very happy man. > > >> However, that requires a linear intensity response from the sensor and the >> same size of the steps. If you just put 16bit within the same dynamic range >> that is covered by the 12 bit you may get better nuances but not dynamic >> range >> > > That's understood. :-) > > I assume the CCD itself, or maybe its surroundig circuitry, has a > theoretical maximum dynamic range as well. IIRC, this has been > mentioned on PDML recently too, but, alas for my attention...:-( > I always mention this when the sensor size and/or dynamic range discussion comes up ;-) According to sources on the Net, the current 6MP sensors have a range corresponding to slightly more than 6 "steps", or somewhat less that the full range of 16 bits. However, the full range is not really usable due to noise; noise essentially means that the output for the same exposure level may vary between several steps next to each other. Apparently, the noise in the sensors used up to now will typically correspond to 10 levels or so, equivalent to 3 or 4 bits. In other words, if you were to use 16 bits, the lower 4 would probably contain little more than random data caused by the noise. This means you are left with a usable range corresponding to 12 bits. With a 10MP sensor of the same size, the number of levels should be reduced to something like 35000, meaning that the range even before you consider the noise is closer to 15 bits than 16. And with the "old" amount of noise, even 12 bits would be stretching things... So, 16 "real" bits seems unrealistic to me. The noise can probably be reduced, but I'm sure it will never be 0, and to change the actual number of steps in the sensor, I'm assuming you have to do something radical e.g. to the material used. I'm not 100% sure that the numbers I found are reliable, though. Here is one of my sources http://micro.magnet.fsu.edu/primer/digitalimaging/concepts/dynamicrange.html - Toralf -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
> Fra: "Peter Loveday" <[EMAIL PROTECTED]> > > > In theory I think you could gain 4 stops. One stop is x2 > > more light, so x2^4 should translate to 4 stops. > > Yep, 1 stop == 1 bit, conveniently. > > > However, that requires a linear intensity response from > > the sensor and the same size of the steps. If you just put > > 16bit within the same dynamic range that is covered by > > the 12 bit you may get better nuances but not dynamic range > > Well, technically you *do* get more dynamic range. Dynamic range is > basically the ratio between the smallest change measurable, and the largest > value measurable. So for 12 bit you basically have 4095:1 dynamic range; > for 16 bit 65535:1 dynamic range. > > What you choose to be maximum determines if you have over-exposure lattitude > or not, which is a different thing altogether. So in 16 bit, you could > shoot 4 stops underexposed, and get the same nuances as 12 bit, but with 4 > stops of over-exposure latitude. > > Nice in theory anyway Of course, in the real world the linearity comes > in to play as you say, but, as discussed previously, theres a point where > sensor noise makes more bits basically meaningless. Yes, you have to distribute your bits between the noise level and the saturation level. Some things, like an increase in the light sensitive area of each pixel or other tricks like reducing dark current, can suppress noise in one ends and other tricks like Fuji does with their sensors may give something in the other end. In addition you can gain a little bit in how you distribute your bits, and maybe that is what they do in the 22bit conversion. Anyway, larger pixels will give an advantage in the range between noise and saturation, so maybe in 645D... DagT -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
> > From: "Peter Loveday" <[EMAIL PROTECTED]> > Date: 2006/09/06 Wed AM 10:48:42 GMT > To: "Pentax-Discuss Mail List" > Subject: Re: Advantage of increased colour depth? > > > In theory I think you could gain 4 stops. One stop is x2 > > more light, so x2^4 should translate to 4 stops. > > Yep, 1 stop == 1 bit, conveniently. > > > However, that requires a linear intensity response from > > the sensor and the same size of the steps. If you just put > > 16bit within the same dynamic range that is covered by > > the 12 bit you may get better nuances but not dynamic range > > Well, technically you *do* get more dynamic range. Dynamic range is > basically the ratio between the smallest change measurable, and the largest > value measurable. So for 12 bit you basically have 4095:1 dynamic range; > for 16 bit 65535:1 dynamic range. But this is not the same as "dynamic range" as has been historically used in photography, where it is taken to mean the range of ability to resolve from light to dark. > > What you choose to be maximum determines if you have over-exposure lattitude > or not, which is a different thing altogether. So in 16 bit, you could > shoot 4 stops underexposed, and get the same nuances as 12 bit, but with 4 > stops of over-exposure latitude. > > Nice in theory anyway Of course, in the real world the linearity comes > in to play as you say, but, as discussed previously, theres a point where > sensor noise makes more bits basically meaningless. > > Love, Light and Peace, > - Peter Loveday > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > - Email sent from www.ntlworld.com Virus-checked using McAfee(R) Software Visit www.ntlworld.com/security for more information -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
> > From: DagT <[EMAIL PROTECTED]> > Date: 2006/09/06 Wed AM 09:43:56 GMT > To: Pentax-Discuss Mail List > Subject: Re: Advantage of increased colour depth? > > In theory I think you could gain 4 stops. One stop is x2 more light, so x2^4 > should translate to 4 stops. > > However, that requires a linear intensity response from the sensor and the > same size of the steps. If you just put 16bit within the same dynamic range > that is covered by the 12 bit you may get better nuances but not dynamic > range > > DagT That's always been my interpretation. > > > Fra: "Jostein Øksne" <[EMAIL PROTECTED]> > > Dato: 2006/09/06 Wed AM 11:20:59 CEST > > Til: "Pentax-Discuss Mail List" > > Emne: Re: Advantage of increased colour depth? > > > > The math is easy. There are as you say 2^4 more values available to > > describe each tone in a channel, and hence the information recorded at > > each pixel is mapped to a larger span of potential values. And that's > > even before the actual colour is computed through the Bayer-thingy. > > > > The main reason for my appreciation of RAW-files over JPG or 8-bit > > TIFF is the difference between 8 and 12-bit colour depth. It gives > > more latitude, just like print film did over slide film. > > > > I still feel more comfortable about using f-stops to describe > > latitude, and it would just be nice to know what to expect in a more > > real-world terms of reference... :-) > > > > Jostein > > > > On 9/6/06, Boris Liberman <[EMAIL PROTECTED]> wrote: > > > Jostein, > > > > > > I think it is easy. With 16 bits vs 12 bits per pixel you have 2^4 - > > > 16 times more information recorded. What use does it make - it would > > > greatly depend on RAW processing software and matching of camera > > > electronics with RAW converter number crunching. > > > > > > > > > -- > > > Boris > > > > > > -- > > > PDML Pentax-Discuss Mail List > > > PDML@pdml.net > > > http://pdml.net/mailman/listinfo/pdml_pdml.net > > > > > > > -- > > PDML Pentax-Discuss Mail List > > PDML@pdml.net > > http://pdml.net/mailman/listinfo/pdml_pdml.net > > > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > - Email sent from www.ntlworld.com Virus-checked using McAfee(R) Software Visit www.ntlworld.com/security for more information -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
> In theory I think you could gain 4 stops. One stop is x2 > more light, so x2^4 should translate to 4 stops. Yep, 1 stop == 1 bit, conveniently. > However, that requires a linear intensity response from > the sensor and the same size of the steps. If you just put > 16bit within the same dynamic range that is covered by > the 12 bit you may get better nuances but not dynamic range Well, technically you *do* get more dynamic range. Dynamic range is basically the ratio between the smallest change measurable, and the largest value measurable. So for 12 bit you basically have 4095:1 dynamic range; for 16 bit 65535:1 dynamic range. What you choose to be maximum determines if you have over-exposure lattitude or not, which is a different thing altogether. So in 16 bit, you could shoot 4 stops underexposed, and get the same nuances as 12 bit, but with 4 stops of over-exposure latitude. Nice in theory anyway Of course, in the real world the linearity comes in to play as you say, but, as discussed previously, theres a point where sensor noise makes more bits basically meaningless. Love, Light and Peace, - Peter Loveday -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
On 9/6/06, DagT <[EMAIL PROTECTED]> wrote: > In theory I think you could gain 4 stops. One stop is x2 more light, so x2^4 > should translate to 4 stops. That's quite a lot. I don't find the raw files from *istD to lack much in dynamic range as it is, so an increase of just 2 stops would probably make me a very happy man. > However, that requires a linear intensity response from the sensor and the > same size of the steps. If you just put 16bit within the same dynamic range > that is covered by the 12 bit you may get better nuances but not dynamic > range That's understood. :-) I assume the CCD itself, or maybe its surroundig circuitry, has a theoretical maximum dynamic range as well. IIRC, this has been mentioned on PDML recently too, but, alas for my attention...:-( Since there are so many factors to limit the theoretical potential, I suppose there will be some increase with diminishing returns going on. -That expanding the colour depth to 16 bits doesn't pay back for the effort and cost, to put it in veeery general terms... Jostein -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
In theory I think you could gain 4 stops. One stop is x2 more light, so x2^4 should translate to 4 stops. However, that requires a linear intensity response from the sensor and the same size of the steps. If you just put 16bit within the same dynamic range that is covered by the 12 bit you may get better nuances but not dynamic range DagT > Fra: "Jostein Øksne" <[EMAIL PROTECTED]> > Dato: 2006/09/06 Wed AM 11:20:59 CEST > Til: "Pentax-Discuss Mail List" > Emne: Re: Advantage of increased colour depth? > > The math is easy. There are as you say 2^4 more values available to > describe each tone in a channel, and hence the information recorded at > each pixel is mapped to a larger span of potential values. And that's > even before the actual colour is computed through the Bayer-thingy. > > The main reason for my appreciation of RAW-files over JPG or 8-bit > TIFF is the difference between 8 and 12-bit colour depth. It gives > more latitude, just like print film did over slide film. > > I still feel more comfortable about using f-stops to describe > latitude, and it would just be nice to know what to expect in a more > real-world terms of reference... :-) > > Jostein > > On 9/6/06, Boris Liberman <[EMAIL PROTECTED]> wrote: > > Jostein, > > > > I think it is easy. With 16 bits vs 12 bits per pixel you have 2^4 - > > 16 times more information recorded. What use does it make - it would > > greatly depend on RAW processing software and matching of camera > > electronics with RAW converter number crunching. > > > > > > -- > > Boris > > > > -- > > PDML Pentax-Discuss Mail List > > PDML@pdml.net > > http://pdml.net/mailman/listinfo/pdml_pdml.net > > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
> > From: "Jostein Øksne" <[EMAIL PROTECTED]> > > Better dynamic range has been mentioned frequently in the discussion > of 16-bit colour, but I don't think I paid enough attention. How much > would 16-bit depth improve the dynamic range over 12-bit in terms of > f-stops? Is this going to be like going from slide film to colour > negatives, or is this on a different scale? > I must admit that I haven't been paying too much attention to this matter but I assumed that the meaning was in relation to colour only and not to exposure. Just poor use of language - on someone's part 8-) Does greater colour depth increase the range or merely the number of subdivisions of a colour? m - Email sent from www.ntlworld.com Virus-checked using McAfee(R) Software Visit www.ntlworld.com/security for more information -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
The math is easy. There are as you say 2^4 more values available to describe each tone in a channel, and hence the information recorded at each pixel is mapped to a larger span of potential values. And that's even before the actual colour is computed through the Bayer-thingy. The main reason for my appreciation of RAW-files over JPG or 8-bit TIFF is the difference between 8 and 12-bit colour depth. It gives more latitude, just like print film did over slide film. I still feel more comfortable about using f-stops to describe latitude, and it would just be nice to know what to expect in a more real-world terms of reference... :-) Jostein On 9/6/06, Boris Liberman <[EMAIL PROTECTED]> wrote: > Jostein, > > I think it is easy. With 16 bits vs 12 bits per pixel you have 2^4 - > 16 times more information recorded. What use does it make - it would > greatly depend on RAW processing software and matching of camera > electronics with RAW converter number crunching. > > > -- > Boris > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: Advantage of increased colour depth?
Jostein, I think it is easy. With 16 bits vs 12 bits per pixel you have 2^4 - 16 times more information recorded. What use does it make - it would greatly depend on RAW processing software and matching of camera electronics with RAW converter number crunching. -- Boris -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Advantage of increased colour depth?
With all the talk of a 22 bit A/D converter for the K10D, and the corresponding speculations of true 16-bit colour depth in the raw-files, there are a couple of things I wonder about. Firstly, I wondered what the competition was doing. In the 35mm realm, Canon use 12-bit colour depth in both 5D and 1DSmkII. I didn't check other models. Leica, however, use 16-bit for the R-series digital back. In the medium format realm, it seems that all the makers except Mamiya use 16-bit. I have checked Sinar, Leaf, PhaseOne and Imacon. Mamiya ZD use 12-bit colour depth, but 14-bit A/D. I couldn't find any info on the A/D conversion for the other brands. Anyway, it seems that 12-bit is a standard for 35mm, and that 16-bit colour rule the medium format world. Better dynamic range has been mentioned frequently in the discussion of 16-bit colour, but I don't think I paid enough attention. How much would 16-bit depth improve the dynamic range over 12-bit in terms of f-stops? Is this going to be like going from slide film to colour negatives, or is this on a different scale? thanks, Jostein -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
