CMYK vs RGB RE: PDF query
Do you need the CMYK option checked? (In other words, are you sending your PDF out to a service bureau using a high-quality printer so it can be printed and bound? That's usually why people are checking the CMYK option.) >From some of the discussion here, I get the idea that people think CMYK is just something you pick on a whim. And in response to an earlier comment that CMYK affects color vividness in the PDF, that happens because CMYK is limited to producing colors by mixing printing inks (a subtractive process that is quite different from the additive mixing of pixels on the screen, i.e. RGB). Additive mixing produces white by its max values (256,256,256). Mixing C, M, and Y inks at max values produces black (albeit not a lovely black, which is why the K is there). If your PDF is only going to the screen or a cheap printer (with minimal control of the color space desired), then RGB is fine and choosing CMYK is really not a smart idea since it takes much longer to distill and would have little or no benefit. Craig P.S. Forgive any simplifications in the above. CMYK printing is a rather complex issue. P.P.S. The color space that can be produced by Cyan, Magenta, Yellow and K (black) printing inks on paper is much more restricted than the color space produced by RGB pixels on a computer screen. If you've ever mixed watercolor paint you know that you can't mix colors with pigment that result in colors that are lighter or more vivid than the colors you start with. Any mixing reduces both the value (lightness/darkness) as well as the vividness (saturation) of the color. -Original Message- From: framers-boun...@lists.frameusers.com [mailto:framers-boun...@lists.frameusers.com] On Behalf Of Syed Zaeem Hosain (syed.hos...@aeris.net) Sent: Saturday, October 18, 2014 6:32 PM To: Robert Lauriston; framers@lists.frameusers.com Subject: RE: PDF query Same here with "Save as PDF", except that with FM 12, it seems that I also need to select the "RGB" checkbox option to make it work correctly. The "CMYK" option does _not_ work properly. I will see if I can find the test documents I sent to Adobe and post them here later ... Z Robert Lauriston said: > At least from FM6 on, I had zero problems with Save as PDF so long as Distiller / Adobe PDF was selected as the printer and I used the same file name as the .book I was saving. Mike Wickham wrote: > Actually, Frame print to PDF was the gold standard. Save as PDF was so buggy that all experts recommended against using it. ___ You are currently subscribed to framers as craig...@hotmail.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/craigede%40hotmail.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info. ___ You are currently subscribed to framers as arch...@mail-archive.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info.
Re: CMYK vs RGB RE: PDF query
Hi Craig, whatever the theoretical and technical differences of RGB and CMYK colours are: The FrameMaker RGB output of CMYK-colours is not even close to how the CMYK output looks like. I am (still) using FM 10, btw. Therefore I always produce CMYK pdfs first and use Acrobat preflighting to get correct RGB pdfs (even if these pdfs are only for the screen). The other way round would not work at all: The "interpretation" of colours in the RGB output by FrameMaker is quite strange (a colleague who only uses Indesign called these colours "tawdry"). I am very glad that FM 10 (unlike FM 12) still seems to work with my CMYK graphic files and CMYK colours. I hope that as part of the Adobe products family, FrameMaker will soon be able to handle colours like Indesign does, with colour profiles and direct (error-free) PDF-X3/PDF-X4 compatible output. Best regards - Tino H. Haida, Berlin Craig Ede: > Do you need the CMYK option checked? (In other words, are you sending your > PDF out to a service bureau using a high-quality printer so it can be > printed and bound? That's usually why people are checking the CMYK option.) > > From some of the discussion here, I get the idea that people think CMYK is > just something you pick on a whim. And in response to an earlier comment > that CMYK affects color vividness in the PDF, that happens because CMYK is > limited to producing colors by mixing printing inks (a subtractive process > that is quite different from the additive mixing of pixels on the screen, > i.e. RGB). > > Additive mixing produces white by its max values (256,256,256). Mixing C, M, > and Y inks at max values produces black (albeit not a lovely black, which is > why the K is there). > > If your PDF is only going to the screen or a cheap printer (with minimal > control of the color space desired), then RGB is fine and choosing CMYK is > really not a smart idea since it takes much longer to distill and would have > little or no benefit. > > Craig > P.S. Forgive any simplifications in the above. CMYK printing is a rather > complex issue. > P.P.S. The color space that can be produced by Cyan, Magenta, Yellow and K > (black) printing inks on paper is much more restricted than the color space > produced by RGB pixels on a computer screen. If you've ever mixed watercolor > paint you know that you can't mix colors with pigment that result in colors > that are lighter or more vivid than the colors you start with. Any mixing > reduces both the value (lightness/darkness) as well as the vividness > (saturation) of the color. > > -Original Message- > From: framers-boun...@lists.frameusers.com > [mailto:framers-boun...@lists.frameusers.com] On Behalf Of Syed Zaeem Hosain > (syed.hos...@aeris.net) > Sent: Saturday, October 18, 2014 6:32 PM > To: Robert Lauriston; framers@lists.frameusers.comSubject: RE: PDF query > > Same here with "Save as PDF", except that with FM 12, it seems that I also > need to select the "RGB" checkbox option to make it work correctly. The > "CMYK" option does _not_ work properly. > > I will see if I can find the test documents I sent to Adobe and post them > here later ... > > Z > > Robert Lauriston said: > >> At least from FM6 on, I had zero problems with Save as PDF so long as > > Distiller / Adobe PDF was selected as the printer and I used the same file > name as the .book I was saving. > > Mike Wickham wrote: > >> Actually, Frame print to PDF was the gold standard. Save as PDF was so > > buggy that all experts recommended against using it. > > ___ ___ You are currently subscribed to framers as arch...@mail-archive.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info.
RE: CMYK vs RGB RE: PDF query
Given the theoretical differences I'm not sure why you would expect RGB output of CMYK colors to be close to what CMYK color should looks like. Think of it this way, if you choose a Pantone color as a spot color, you'd expect it to print exactly like as that Pantone color to paper. But to the screen, who knows? It's be "close" but depends on the color correctness of the particular monitor. Craig > Date: Mon, 20 Oct 2014 03:07:58 +0200 > > whatever the theoretical and technical differences of RGB and CMYK > colours are: > > The FrameMaker RGB output of CMYK-colours is not even close to how the > CMYK output looks like. I am (still) using FM 10, btw. > > ___ You are currently subscribed to framers as arch...@mail-archive.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info.
RE: CMYK vs RGB RE: PDF query
Well, Craig, thats easy to explain: When I use Illustrator or Indesign, a colour will not change its screen representation if I switch from CMYK definition to RGB definition. That is not a miracle or a question of "who knows" (these programs use HSB definitions, and obviously the conversion works very well). With FrameMaker, on the other hand, a CMYK colour will not look "right" neither on screen nor in the resulting PDF. And only with the CMYK print option activated that has been implemented successfully with FM 10, this colour information will be transfered to the PDF correctly. Best regards - Tino H. Haida, Berlin Craig Ede: > Given the theoretical differences I'm not sure why you would expect RGB > output of CMYK colors to be close to what CMYK color should looks like. > > Think of it this way, if you choose a Pantone color as a spot color, you'd > expect it to print exactly like as that Pantone color to paper. But to the > screen, who knows? It's be "close" but depends on the color correctness of > the particular monitor. > > Craig ___ You are currently subscribed to framers as arch...@mail-archive.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info.
RE: CMYK vs RGB RE: PDF query
It’s definitely NOT easy to explain this. Color conversions are COMPLEX. Anyway, RGB -> CMYK conversion is lossy, and CMYK -> RGB is also lossy. What is the point of the RGB switch afterall? Why not just pass through what’s input and remove this switch? Best regards / Med venlig hilsen Jacob Schäffer | Chief Developer _ Grafikhuset (House of Graphics) Paradis Allé 22, Ramløse DK-3200 Helsinge, Denmark Mobile: +45 2021 1958 Phone: +45 4848 0096 Email: <mailto:j...@grafikhuset.dk> j...@grafikhuset.dk Web: <http://design.grafikhuset.dk/> http://design.grafikhuset.dk From: framers-boun...@lists.frameusers.com [mailto:framers-boun...@lists.frameusers.com] On Behalf Of Heiko Haida Sent: 20. oktober 2014 16:22 To: Craig Ede Cc: framers Subject: RE: CMYK vs RGB RE: PDF query Well, Craig, thats easy to explain: When I use Illustrator or Indesign, a colour will not change its screen representation if I switch from CMYK definition to RGB definition. That is not a miracle or a question of "who knows" (these programs use HSB definitions, and obviously the conversion works very well). With FrameMaker, on the other hand, a CMYK colour will not look "right" neither on screen nor in the resulting PDF. And only with the CMYK print option activated that has been implemented successfully with FM 10, this colour information will be transfered to the PDF correctly. Best regards - Tino H. Haida, Berlin Craig Ede: Given the theoretical differences I'm not sure why you would expect RGB output of CMYK colors to be close to what CMYK color should looks like. Think of it this way, if you choose a Pantone color as a spot color, you'd expect it to print exactly like as that Pantone color to paper. But to the screen, who knows? It's be "close" but depends on the color correctness of the particular monitor. Craig ___ You are currently subscribed to framers as arch...@mail-archive.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info.
RE: CMYK vs RGB RE: PDF query
Hi Jacob, my point here is: The CMYK option in FM is not something like a fancy gadget (that is how I understood what Craig said earlier), but essential for a correct colour representation in certain constellations. Here is an example, I enclose a screenshot: 2 rectangular objects are visible, with colours defined as CMYK = 100/70/0/0 and 100/0/20/20. To the left, that is the (correct) representation in Illustrator. To the right, thats what it looks like in FrameMaker (obviously not "correct"). In the middle that is the PDF output with the CMYK option not activated (which is the standard - and only possible - behaviour of all older FM version up to FM 10). With the CMYK option activated on the other hand, the PDF output would in fact look exactly like in Illustrator. And if this PDF is converted afterwards to RGB via Acrobat preflight, the colours would still be perfect on screen. If you know a better or easier way or working settings for FM or Acrobat, please tell me. Best regards - Tino H. Haida, Berlin Jacob Schäffer: > It's definitely NOT easy to explain this. Color conversions are COMPLEX. > Anyway, RGB -> CMYK conversion is lossy, and CMYK -> RGB is also lossy. > > What is the point of the RGB switch afterall? Why not just pass through > what's input and remove this switch? > > Best regards / Med venlig hilsen > > Jacob Schäffer | Chief Developer > > - > > Grafikhuset (House of Graphics) > Paradis Allé 22, Ramløse > DK-3200 Helsinge, Denmark > > Mobile: +45 2021 1958 > Phone: +45 4848 0096 > Email: j...@grafikhuset.dk > Web: http://design.grafikhuset.dk [1] > > FROM: framers-boun...@lists.frameusers.com > [mailto:framers-boun...@lists.frameusers.com] ON BEHALF OF Heiko Haida > SENT: 20. oktober 2014 16:22 > TO: Craig Ede > CC: framers > SUBJECT: RE: CMYK vs RGB RE: PDF query > > Well, Craig, > > thats easy to explain: > When I use Illustrator or Indesign, a colour will not change its screen > representation if I switch from CMYK definition to RGB definition. That is > not a miracle or a question of "who knows" (these programs use HSB > definitions, and obviously the conversion works very well). > With FrameMaker, on the other hand, a CMYK colour will not look "right" > neither on screen nor in the resulting PDF. > And only with the CMYK print option activated that has been implemented > successfully with FM 10, this colour information will be transfered to the > PDF correctly. > > Best regards - Tino H. Haida, Berlin > > Craig Ede: > >> Given the theoretical differences I'm not sure why you would expect RGB >> output of CMYK colors to be close to what CMYK color should looks like. >> >> Think of it this way, if you choose a Pantone color as a spot color, you'd >> expect it to print exactly like as that Pantone color to paper. But to the >> screen, who knows? It's be "close" but depends on the color correctness of >> the particular monitor. >> >> Craig Links: -- [1] http://design.grafikhuset.dk/ ___ You are currently subscribed to framers as arch...@mail-archive.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info.
Re: CMYK vs RGB RE: PDF query
A screen capture of a RGB representation of a CMYK image in a professional graphics program isn't a very common requirement. What does the screen capture from Illustrator look like if you simply paste it into Windows Paint? On Mon, Oct 20, 2014 at 12:11 PM, Heiko Haida wrote: > > Hi Jacob, > > my point here is: > The CMYK option in FM is not something like a fancy gadget (that is how I > understood what Craig said earlier), but essential for a correct colour > representation in certain constellations. > > Here is an example, I enclose a screenshot: 2 rectangular objects are > visible, with colours defined as CMYK = 100/70/0/0 and 100/0/20/20. > > To the left, that is the (correct) representation in Illustrator. To the > right, thats what it looks like in FrameMaker (obviously not "correct"). In > the middle that is the PDF output with the CMYK option not activated (which > is the standard - and only possible - behaviour of all older FM version up to > FM 10). > > With the CMYK option activated on the other hand, the PDF output would in > fact look exactly like in Illustrator. > And if this PDF is converted afterwards to RGB via Acrobat preflight, the > colours would still be perfect on screen. > > If you know a better or easier way or working settings for FM or Acrobat, > please tell me. ___ You are currently subscribed to framers as arch...@mail-archive.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info.
RE: CMYK vs RGB RE: PDF query
Try this thread for some exploration of these issues. I really do not think
"colour correctness of the monitor" is the problem here. It's just that
FrameMaker's colour handling hasn't been updated since about 1988...
https://forums.adobe.com/thread/1495005
Message: 7
Date: Mon, 20 Oct 2014 08:35:13 -0500
From: Craig Ede
To: "i...@heiko-haida.de" , framers
Subject: RE: CMYK vs RGB RE: PDF query
Message-ID:
Content-Type: text/plain; charset="iso-8859-1"
Given the theoretical differences I'm not sure why you would expect RGB output
of CMYK colors to be close to what CMYK color should looks like.
Think of it this way, if you choose a Pantone color as a spot color, you'd
expect it to print exactly like as that Pantone color to paper. But to the
screen, who knows? It's be "close" but depends on the color correctness of the
particular monitor.
Craig
*** Confidentiality Notice: This e-mail, including any associated or attached
files, is intended solely for the individual or entity to which it is
addressed. This e-mail is confidential and may well also be legally privileged.
If you have received it in error, you are on notice of its status. Please
notify the sender immediately by reply e-mail and then delete this message from
your system. Please do not copy it or use it for any purposes, or disclose its
contents to any other person. This email comes from a division of the Invensys
Group, owned by Invensys Limited, which is a company registered in England and
Wales with its registered office at 3rd Floor, 40 Grosvenor Place, London, SW1X
7AW (Registered number 166023). For a list of European legal entities within
the Invensys Group, please select the Legal Entities link at invensys.com.
Invensys Limited is owned by the Schneider-Electric Group.
You may contact Invensys Limited on +44 (0)20 3155 1200 or e-mail
recept...@invensys.com. This e-mail and any attachments thereto may be subject
to the terms of any agreements between Invensys (and/or its subsidiaries and
affiliates) and the recipient (and/or its subsidiaries and affiliates).
___
You are currently subscribed to framers as arch...@mail-archive.com.
Send list messages to framers@lists.frameusers.com.
To unsubscribe send a blank email to
framers-unsubscr...@lists.frameusers.com
or visit
http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com
Send administrative questions to listad...@frameusers.com. Visit
http://www.frameusers.com/ for more resources and info.
RE: CMYK vs RGB RE: PDF query
Are colour conversions really that "complex"?
They're just converting colour coordinates in one colour-space to those in
another, using some straightforward formulae that are hidden under the hood.
(The choice of formula, and what to do if a colour is 'out of gamut', depends
on the 'rendering intent', of which we usually have a choice of four).
The conversions will give 'round-tripping' errors if they're out of gamut.
This is why better Adobe software (Illustrator, Photoshop, InDesign) maps RGB
and CMYK via a device-independent ("LaB") representation, rather than straight
from one to the other.
The problem with FrameMaker is that the conversion algorithms it uses are crude
rubbish. This is why they frequently give such awful results, not because it's
"complex".
>From previous threads on the Adobe Forums, it seems that the conversion
>formula Frame uses is:
RGB to CMYK:
C = max(R, G, B) - R
M = max(R, G, B) - G
Y = max(R, G, B) - B
K = 100 - max(R, G, B)
CMYK to RGB:
R = min(100 - K - C, 0)
G = min(100 - K - M, 0)
B = min(100 - K - Y, 0)
...which gives rubbish results.
David
From: Jacob Sch?ffer (Grafikhuset)
To: , "'Craig Ede'"
Cc: 'framers'
Subject: RE: CMYK vs RGB RE: PDF query
Message-ID: <00a601cfec93$39b38e10$ad1aaa30$@grafikhuset.dk>
Content-Type: text/plain; charset="utf-8"
It?s definitely NOT easy to explain this. Color conversions are COMPLEX.
Anyway, RGB -> CMYK conversion is lossy, and CMYK -> RGB is also lossy.
What is the point of the RGB switch afterall? Why not just pass through what?s
input and remove this switch?
*** Confidentiality Notice: This e-mail, including any associated or attached
files, is intended solely for the individual or entity to which it is
addressed. This e-mail is confidential and may well also be legally privileged.
If you have received it in error, you are on notice of its status. Please
notify the sender immediately by reply e-mail and then delete this message from
your system. Please do not copy it or use it for any purposes, or disclose its
contents to any other person. This email comes from a division of the Invensys
Group, owned by Invensys Limited, which is a company registered in England and
Wales with its registered office at 3rd Floor, 40 Grosvenor Place, London, SW1X
7AW (Registered number 166023). For a list of European legal entities within
the Invensys Group, please select the Legal Entities link at invensys.com.
Invensys Limited is owned by the Schneider-Electric Group.
You may contact Invensys Limited on +44 (0)20 3155 1200 or e-mail
recept...@invensys.com. This e-mail and any attachments thereto may be subject
to the terms of any agreements between Invensys (and/or its subsidiaries and
affiliates) and the recipient (and/or its subsidiaries and affiliates).
___
You are currently subscribed to framers as arch...@mail-archive.com.
Send list messages to framers@lists.frameusers.com.
To unsubscribe send a blank email to
framers-unsubscr...@lists.frameusers.com
or visit
http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com
Send administrative questions to listad...@frameusers.com. Visit
http://www.frameusers.com/ for more resources and info.
RE: CMYK vs RGB RE: PDF query
Yes, I think color conversions are that complex.
RGB was designed for monitors allowing a broad range of additive colors in the
form of light (i.e. lit pixels).
CMYK was designed for subtractive printing to paper offering a restricted range
of those colors; many of the RGB colors being "out of gamut" for CMYK, meaning
there is no formula to convert them.
Nobody serious is printing high-quality hardcopy using R, G, and B inks. And
I'm not sure why one would want to use CMYK to print to the screen.
Craig
> From: david.da...@non.schneider-electric.com
> To: framers@lists.frameusers.com
> Date: Wed, 22 Oct 2014 03:34:52 -0500
> Subject: RE: CMYK vs RGB RE: PDF query
>
> Are colour conversions really that "complex"?
> They're just converting colour coordinates in one colour-space to those in
> another, using some straightforward formulae that are hidden under the hood.
> (The choice of formula, and what to do if a colour is 'out of gamut', depends
> on the 'rendering intent', of which we usually have a choice of four).
> The conversions will give 'round-tripping' errors if they're out of gamut.
> This is why better Adobe software (Illustrator, Photoshop, InDesign) maps RGB
> and CMYK via a device-independent ("LaB") representation, rather than
> straight from one to the other.
> The problem with FrameMaker is that the conversion algorithms it uses are
> crude rubbish. This is why they frequently give such awful results, not
> because it's "complex".
>
> From previous threads on the Adobe Forums, it seems that the conversion
> formula Frame uses is:
>
> RGB to CMYK:
> C = max(R, G, B) - R
> M = max(R, G, B) - G
> Y = max(R, G, B) - B
> K = 100 - max(R, G, B)
>
> CMYK to RGB:
> R = min(100 - K - C, 0)
> G = min(100 - K - M, 0)
> B = min(100 - K - Y, 0)
>
> ...which gives rubbish results.
>
> David
>
>
>
> From: Jacob Sch?ffer (Grafikhuset)
> To: , "'Craig Ede'"
> Cc: 'framers'
> Subject: RE: CMYK vs RGB RE: PDF query
> Message-ID: <00a601cfec93$39b38e10$ad1aaa30$@grafikhuset.dk>
> Content-Type: text/plain; charset="utf-8"
>
> It?s definitely NOT easy to explain this. Color conversions are COMPLEX.
> Anyway, RGB -> CMYK conversion is lossy, and CMYK -> RGB is also lossy.
>
>
>
> What is the point of the RGB switch afterall? Why not just pass through
> what?s input and remove this switch?
>
> *** Confidentiality Notice: This e-mail, including any associated or attached
> files, is intended solely for the individual or entity to which it is
> addressed. This e-mail is confidential and may well also be legally
> privileged. If you have received it in error, you are on notice of its
> status. Please notify the sender immediately by reply e-mail and then delete
> this message from your system. Please do not copy it or use it for any
> purposes, or disclose its contents to any other person. This email comes from
> a division of the Invensys Group, owned by Invensys Limited, which is a
> company registered in England and Wales with its registered office at 3rd
> Floor, 40 Grosvenor Place, London, SW1X 7AW (Registered number 166023). For a
> list of European legal entities within the Invensys Group, please select the
> Legal Entities link at invensys.com. Invensys Limited is owned by the
> Schneider-Electric Group.
>
> You may contact Invensys Limited on +44 (0)20 3155 1200 or e-mail
> recept...@invensys.com. This e-mail and any attachments thereto may be
> subject to the terms of any agreements between Invensys (and/or its
> subsidiaries and affiliates) and the recipient (and/or its subsidiaries and
> affiliates).
> ___
>
>
> You are currently subscribed to framers as craig...@hotmail.com.
>
> Send list messages to framers@lists.frameusers.com.
>
> To unsubscribe send a blank email to
> framers-unsubscr...@lists.frameusers.com
> or visit
> http://lists.frameusers.com/mailman/options/framers/craigede%40hotmail.com
>
> Send administrative questions to listad...@frameusers.com. Visit
> http://www.frameusers.com/ for more resources and info.
___
You are currently subscribed to framers as arch...@mail-archive.com.
Send list messages to framers@lists.frameusers.com.
To unsubscribe send a blank email to
framers-unsubscr...@lists.frameusers.com
or visit
http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com
Send administrative questions to listad...@frameusers.com. Visit
http://www.frameusers.com/ for more resources and info.
Re: CMYK vs RGB RE: PDF query
So far as I know, the only reason to use CMYK on screen is for
prepress work for something that's going to be professionally printed.
So the only context I can think of where you'd care about accurate
screen captures of CMYK images on screen would be if you were writing
online help for InDesign, Illustrator, or Photoshop.
On Wed, Oct 22, 2014 at 7:34 AM, Craig Ede wrote:
>
>
> Yes, I think color conversions are that complex.
> RGB was designed for monitors allowing a broad range of additive colors in
> the form of light (i.e. lit pixels).
> CMYK was designed for subtractive printing to paper offering a restricted
> range of those colors; many of the RGB colors being "out of gamut" for CMYK,
> meaning there is no formula to convert them.
> Nobody serious is printing high-quality hardcopy using R, G, and B inks. And
> I'm not sure why one would want to use CMYK to print to the screen.
>
> Craig
>> From: david.da...@non.schneider-electric.com
>> To: framers@lists.frameusers.com
>> Date: Wed, 22 Oct 2014 03:34:52 -0500
>> Subject: RE: CMYK vs RGB RE: PDF query
>>
>> Are colour conversions really that "complex"?
>> They're just converting colour coordinates in one colour-space to those in
>> another, using some straightforward formulae that are hidden under the hood.
>> (The choice of formula, and what to do if a colour is 'out of gamut',
>> depends on the 'rendering intent', of which we usually have a choice of
>> four).
>> The conversions will give 'round-tripping' errors if they're out of gamut.
>> This is why better Adobe software (Illustrator, Photoshop, InDesign) maps
>> RGB and CMYK via a device-independent ("LaB") representation, rather than
>> straight from one to the other.
>> The problem with FrameMaker is that the conversion algorithms it uses are
>> crude rubbish. This is why they frequently give such awful results, not
>> because it's "complex".
>>
>> From previous threads on the Adobe Forums, it seems that the conversion
>> formula Frame uses is:
>>
>> RGB to CMYK:
>> C = max(R, G, B) - R
>> M = max(R, G, B) - G
>> Y = max(R, G, B) - B
>> K = 100 - max(R, G, B)
>>
>> CMYK to RGB:
>> R = min(100 - K - C, 0)
>> G = min(100 - K - M, 0)
>> B = min(100 - K - Y, 0)
>>
>> ...which gives rubbish results.
>>
>> David
>>
>>
>>
>> From: Jacob Sch?ffer (Grafikhuset)
>> To: , "'Craig Ede'"
>> Cc: 'framers'
>> Subject: RE: CMYK vs RGB RE: PDF query
>> Message-ID: <00a601cfec93$39b38e10$ad1aaa30$@grafikhuset.dk>
>> Content-Type: text/plain; charset="utf-8"
>>
>> It?s definitely NOT easy to explain this. Color conversions are COMPLEX.
>> Anyway, RGB -> CMYK conversion is lossy, and CMYK -> RGB is also lossy.
>>
>>
>>
>> What is the point of the RGB switch afterall? Why not just pass through
>> what?s input and remove this switch?
>>
>> *** Confidentiality Notice: This e-mail, including any associated or
>> attached files, is intended solely for the individual or entity to which it
>> is addressed. This e-mail is confidential and may well also be legally
>> privileged. If you have received it in error, you are on notice of its
>> status. Please notify the sender immediately by reply e-mail and then delete
>> this message from your system. Please do not copy it or use it for any
>> purposes, or disclose its contents to any other person. This email comes
>> from a division of the Invensys Group, owned by Invensys Limited, which is a
>> company registered in England and Wales with its registered office at 3rd
>> Floor, 40 Grosvenor Place, London, SW1X 7AW (Registered number 166023). For
>> a list of European legal entities within the Invensys Group, please select
>> the Legal Entities link at invensys.com. Invensys Limited is owned by the
>> Schneider-Electric Group.
>>
>> You may contact Invensys Limited on +44 (0)20 3155 1200 or e-mail
>> recept...@invensys.com. This e-mail and any attachments thereto may be
>> subject to the terms of any agreements between Invensys (and/or its
>> subsidiaries and affiliates) and the recipient (and/or its subsidiaries and
>> affiliates).
>> ___
>>
>>
>> You are currently subscribed to framers as craig...@hotmail.com.
>>
>> Send list messages to framers@lists.frameusers.com.
>>
>> To unsubscribe send a blank email to
>> framers-unsubscr...@lists.frameusers.c
RE: CMYK vs RGB RE: PDF query
Well Adobe's other software (Illustrator, InDesign, Photoshop) and even Microsoft's Office suite seems to find it a lot less "complex" than FrameMaker does A screen-shot in a technical manual does come from an RGB colour space. Likewise, a photograph taken with a digital camera is natively an RGB thing. If they ever gets printed on paper on colour, then CMYK inks will be used to print it (there are no RGB inks!) What's supposed to happen is that they can be included in your PDF output as RGB items, tagged with their respective colour profiles (sRGB for a screenshot, or something more fancy if the camera's manufacturer supplies their own profile), and the PDF is output-device-independent. So if you view the PDF on screen, the OS and display driver take account of the monitor's declared output capabilities, and render the RGB items appropriately; Conversely, if you're printing the PDF on paper, the OS and printer driver connive between themselves to choose appropriate CYMK values to render the RGB items on the page. Trying to convert to CMYK up front in FrameMaker and thus pre-empt the printer's capabilities is a mug's game (and vice versa if you have natively CMYK or Pantone material in your PDF). From: Craig Ede [mailto:craig...@hotmail.com] Sent: 22 October 2014 15:35 To: Davis, David; framers Subject: RE: CMYK vs RGB RE: PDF query Yes, I think color conversions are that complex. RGB was designed for monitors allowing a broad range of additive colors in the form of light (i.e. lit pixels). CMYK was designed for subtractive printing to paper offering a restricted range of those colors; many of the RGB colors being "out of gamut" for CMYK, meaning there is no formula to convert them. Nobody serious is printing high-quality hardcopy using R, G, and B inks. And I'm not sure why one would want to use CMYK to print to the screen. Craig __ *** Confidentiality Notice: This e-mail, including any associated or attached files, is intended solely for the individual or entity to which it is addressed. This e-mail is confidential and may well also be legally privileged. If you have received it in error, you are on notice of its status. Please notify the sender immediately by reply e-mail and then delete this message from your system. Please do not copy it or use it for any purposes, or disclose its contents to any other person. This email comes from a division of the Invensys Group, owned by Invensys Limited, which is a company registered in England and Wales with its registered office at 3rd Floor, 40 Grosvenor Place, London, SW1X 7AW (Registered number 166023). For a list of European legal entities within the Invensys Group, please select the Legal Entities link at invensys.com. Invensys Limited is owned by the Schneider-Electric Group. You may contact Invensys Limited on +44 (0)20 3155 1200 or e-mail recept...@invensys.com. This e-mail and any attachments thereto may be subject to the terms of any agreements between Invensys (and/or its subsidiaries and affiliates) and the recipient (and/or its subsidiaries and affiliates). ___ You are currently subscribed to framers as arch...@mail-archive.com. Send list messages to framers@lists.frameusers.com. To unsubscribe send a blank email to framers-unsubscr...@lists.frameusers.com or visit http://lists.frameusers.com/mailman/options/framers/archive%40mail-archive.com Send administrative questions to listad...@frameusers.com. Visit http://www.frameusers.com/ for more resources and info.
