[filmscanners] Re: film scanner
Hi Brad, You are correct, I had a laps of memory that the person was using a Mac. I do not believe the Mac version exists yet. Art Brad Smith wrote: Art, If I remember correctly, they only wrote a Windows version. Have they done a Mac version and I've missed it? The person asking the question said he was running a Mac. Brad Smith On 8/28/02 4:22 PM, Arthur Entlich [EMAIL PROTECTED] wrote: ... ... ... Further, Polaroid supplied a free plug and and separate scratch and dust filter which is pretty effective once you learn how to use it, for the dust that does show. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Dynamic range
Todd, My primary point was that with DyR defined as Dmax - Dmin, as it is by the ISO, it is the range between the minimum discernable signal (which is what the ISO calls Dmax) and the maximum signal before clipping (which is what the ISO calls Dmin). Period. But what do you mean when you say that dynamic range is a range? Dynamic range is _always_ a ratio. If it's not, it's something different. For example: ISO DSC dynamic range ratio of the maximum luminance level that appears unclipped to the minimum luminance level that can be reproduced with an incremental signal to temporal noise ratio of at least 1, as determined according to ISO 15739. http://www.pima.net/standards/iso/tc42/wg18/ISO15739/N4953_FDIS15739%20_E_.p df In the definition you quote above, Dmax - Dmin, Dmax and Dmin will be log values, and thus the expression Dmax - Dmin _is_ a ratio. (I suppose these should all be Dmin - Dmax g.) These values can be obtained from testing, and the bit-depth/resolution within that range is immaterial to the DEFINITION of DyR. It may be material to the values you will measure in testing, but it is immaterial to the definition/formula. Yes, I think, sort of, maybe. If you are looking at the analog signal prior to the A/D converter. But the bit-depth is material to the scanner user, since if it is inadequate, then the quantization error will be larger than the noise, and value of the minimum discernable signal rises. If the bit depth is excessive, then the noise becomes the limiting factor, since the device will return a distribution of random values for a given density on the film. If you start throwing away excessive bits, the range of the distribution of those random values will get smaller and smaller... As to your point that scanners report density ranges as values... You say a 1-bit scanner may assign a value of zero to any tone from black to mid gray... Okay, Yes. but do you realize that the range that Austin is using as his Dmin for the ISO formula is the ENTIRE density range of the scanner? Austin's explained this: in any dynamic range calculation, the maximum signal level can be seen as corresponding to the range of levels handled, assuming the minimum level is defined. The noise (or minimum recognizable signal level) (and the maximum signal level) defines how many meaningful steps the maximum signal level is from the minimum signal level. That's all dynamic range is: the number of meaningful steps from min to max. That's normally expressed as a ratio... If a 1-bit scanner can assign any range a value that is 50% of its density range, what bit depth scanner is it that will assign a signal the entire scanners density range? See above With all due respect, I believe the type of ranges you are speaking to (quite small for highbit scanners) is totally disproportionate to the discussion at hand. My point is that a value reported by a scanner corresponds to a range of possible values in the film, and that the size of that range is given by the worse of the noise in the electronics or the bit resolution of the scanner. David J. Littleboy [EMAIL PROTECTED] Tokyo, Japan Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Dynamic range
Hi Todd, This paper appears to speak to many of the issues discussed in this thread: http://www.analog.com/library/whitepapers/dsp/32bit_wa.html#3 I had a chance to look over that paper. The diagram you mention (I believe you were referring to the sinusoidal wave +-5V signal...) that looked like the Higgins one, though is similar, is being used to show an example of 2's compliment arithmetic. Nothing really to do with dynamic range, as far as our discussion that is. It says in a few spots, basically, that more bits is more dynamic range...and when talking about what dynamic range N bits can hold...that's true. Obviously, in a scanner, more bits may not give the SCANNER more dynamic range, but you certainly need a minimum number of bits to be able to represent all the different values. The definitions they use for dynamic range, as I've said in another post, are the same as I've been using, just don't forget that subtraction in logs is the same as division using non-log numbers. See my other post on that... This paper has a lot of superfluous information that is particular to DSPs and audio, and not as applicable to the scanning issues we've been talking about. Most scanners don't use DSPs that I'm aware of (at least the consumer ones, like the SS4k etc.), the Leaf happens to...BTW, one for each channel. The paper also says, quite clearly Note that the 6-dB-Per-Bit-Rule is an approximation to calculating the actual dynamic range for a given word width., as well as In theoretical terms, there is an increase in the signal-to-quantization noise or dynamic range by approximately 6 dB for each bit added to the word-length of an ADC, DAC or DSPwhich says that the dynamic range is DIRECTLY related to the number of bits, and each bit gives you 6dB more dynamic range for audio. Of course, as we've discussed, that is purely talking about being able to represent all the numbers of a particular dynamic range...it has nothing to do with whether the bits are actually good. If you do the calculations your self, it shows how they arrived at that: 2 bits = 20log2**2 = 12dB 3 bits = 20log2**3 = 18dB Funny how that works out... So, I simply don't see anything that's in that paper that conflicts with what I've said. Perhaps you can elaborate on, specifically, where you believe the difference is. Don't get caught up in any of the DSP stuff...just stick to what they write about bits and dynamic range for the A/D, that may give you less confusion. BTW, the decibel (dB - deci being 10 BTW, so 10 deci-bels is 1 bel...) is defined as 10log10 (power ratio), but since power goes as the square of voltage or current (for constant impedance), the log of voltage or current ratios can be expressed in dB, with a factor of 20 instead of 10...and since that entire paper is talking about audio, they use 20 as the dynamic range multiplier. Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Vuescan/FS2710
alternatvely, if you just want to follow what is happening there concerning vuescan, try this link to google groups (It's copied from the vuescan site): http://groups.google.com/advanced_group_search?hl=enas_ugroup=comp.periphs. scannersas_q=VueScanas_scoring=d you can add your own search parameters [the newsgroup is BIG], e.g. 2710 - Original Message - From: Ken Durling [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, August 29, 2002 12:01 AM Subject: [filmscanners] Re: Vuescan/FS2710 On Wed, 28 Aug 2002 12:07:17 -0600, you wrote: I would like to monitor comp.periphs.scanners would you please let me know how I can get on this e-mail(?) list. Thank you, John John - It's not an e-mail list, but a newsgroup that you subscribe to. I don't know what newsreader you're using, but basically you select the group you want and hit subscribe in whatever keystroke succession is pertinent to your reader. Ken -- -- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Dynamic range
on 8/29/02 5:42 PM, Austin Franklin at [EMAIL PROTECTED] wrote: Roy, I can't figure out why you and Austin have such a mental block about ranges and ratios. And I can't figure out why you want to argue about this. Every reference I've cited (and others have cited) agrees with me completely...I still don't know what on earth you're trying to claim...as you keep changing it. Austin, I've never, never changed my claim. My Claim has always been pure and simple: Dynamic (from the Greek dynamo: power) Range is the range of possible power levels. The range has a maximum power and a minimum power. The DyR equation calculates the SIZE of that power range -- that SIZE (of the Dynamic Range) is always specified as a ratio or the log of that ratio. --- the end, that's it --- All the stuff about number of levels and resolution are artifacts of the digital process and not part of the DyR concept which existed way before the word digital was even coined. The digital world breaks things up into discrete levels which you can count, but that in no way changes the actually concept of Dynamic Range. In all the situations we're talking about, they are just plain one and the same. Dynamic Range is a ratio AND its a range -- Can you point me to ANYWHERE on earth that says something to the effect we have a dynamic range that goes from .01 to 3.2 or something like that? No, because dynamic range is ONE number, as clearly specified in EVERY dynamic range equation. It is NOT a RANGE of numbers. The ONE number is the SIZE of the RANGE. Yes, a range has a max and a min. But the SIZE of the range is ONE number -- and it can be mathematically calculated with a subtraction OR with a ratio. In the dynamic range case we always calculate the SIZE of the range with a ratio = max/min. You don't seem to have trouble when someone says density range and Dmax - Dmin. Why the hangup when the adjective is changed? A specification of dynamic range, say, 92dB, does NOT give you ANY range, Like I said it gives you the SIZE of the RANGE of power levels. it merely gives you the information about the relationship over a (unknown) range. You are confusing that dynamic range IS calculated OVER a specified range, but it is NOT a range in and of it self, and simply because you calculate it FROM a specified range, does not make it a range. That's silly. Similarly, Dmax - Dmin is a ratio and its also a range How's that? That's a MINUS sign, not a from - to in the dynamic range equation. You certainly could SAY that something over a range from dMin to dMax, there is nothing wrong with that, but that is NOT dynamic range, that's simply a density range. -- looks like a density range (a range as well and its a ratio). They are ALL the same kind of animal. Well, no...density and dynamic range are similar, only in that they are both represented typically in log values, but that's a so what, and doesn't make them the same. Todd is reading and interpreting the ISO standard and that audio paper entirely correctly. Listen to him. Todd is confused by this probably because you, and some others, have some real misunderstandings as to what dynamic range is, and you are simply so prolific, and so out of focus, and want to argue the minutiae instead of understand the overall concept, no wonder people are confused. Well, there's a difference of opinion about who's mistaken. So much for your promise to not post any more on this... Austin Roy Harrington [EMAIL PROTECTED] Black White Photography Gallery http://www.harrington.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Dynamic range
Julian Robinson [EMAIL PROTECTED] writes: ... It is not hard to understand - 1dB is a small range (about 1.26 to 1), 100dB is a big range (100 to 1). The range we are discussing is the range from MDS to max signal, which in scanner case is Dmax to Dmin. There are _two_ ways to talk about Dmax to Dmin, you can talk about their absolute values (transmittances in the range 0 to 1, for example) as a density range or you can talk about the ratio of Dmax to MDS (or Dmin to MDS depending on the definitions) as the dynamic range. If you claim that these are equivalent, then Austin and I disagree, but if you think they are different, then we all agree. That's all there is here. David J. Littleboy [EMAIL PROTECTED] Tokyo, Japan Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Dynamic range
There's a large number of ways you can write down numbers to define a range. There is only one way in common use to express a range in a single number that is independent of gain and other things that are irrelevant - as a ratio. You can express that ratio in a number of ways, dimensionless plain number or as a log value etc. Julian At 12:55 30/08/02, you wrote: Julian Robinson [EMAIL PROTECTED] writes: ... It is not hard to understand - 1dB is a small range (about 1.26 to 1), 100dB is a big range (100 to 1). The range we are discussing is the range from MDS to max signal, which in scanner case is Dmax to Dmin. There are _two_ ways to talk about Dmax to Dmin, you can talk about their absolute values (transmittances in the range 0 to 1, for example) as a density range or you can talk about the ratio of Dmax to MDS (or Dmin to MDS depending on the definitions) as the dynamic range. If you claim that these are equivalent, then Austin and I disagree, but if you think they are different, then we all agree. That's all there is here. David J. Littleboy [EMAIL PROTECTED] Tokyo, Japan Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Dynamic range
To David and Austin Austin replies to me: Let me repeat, this paper says DyR is: if noise is present, the difference between the loudest (maximum level) signal to the noise floor. This is in contrast to Austin who says DyR is: (maximum signal level - minimum signal level) / noise) They are exactly the same equations, as I've shown countless times...one is in log and one is non-log. Subtraction using log numbers is EXACTLY the same as division using non-log numbers. Look, I'm not mathematically minded, and I do sometimes confuse what types of values are expressed in log form and which aren't. So I can't always be trusted to use the DyR equation in it's proper form, i.e., max - min vs max/min. But look at those slips as typos and don't assume it means I don't appreciate that when used properly both mean the same thing. I am confused in usage and execution, not concept. So, in summary, I believe this paper shows that dynamic range is a range, the range between the noise floor and clipping - which is in opposition to Austin's premise that DyR is a resolution. Come on, Todd, the paper CLEARLY says dynamic range is a resolution. Why on earth do they say so many times that you need so many bits to represent a particular dynamic range? Forget the diagrams, you are confused by them, as they clearly represent two different things. I think Roy and Julian have answered this better than I could. I would just say that to really get at this I think it needs to be looked at from an analog perspective, so we do not let the relationship which exists between bits and DyR in the digital world confuse us as to what DyR IS. The bits are merely carriers of DyR, they are not what DyR is. I know you and David know this, but you say thinks like above which confuse the issue. Here's another obscure example to demonstrate my point that will make the purists puke... but lets just try it. Say we have a vessel of freshly squeezed milk. Let's pretend there are some curds or solids in the milk which have settled to the bottom. Let's call them noise. And there is some creme which has risen to the top. Lets call that saturation or clipping. I'm going to say the aspect of the milk I am interested in is the skim milk between. That volume of milk is my Dynamic Volume. For every similar vessel I have of fresh squeezed milk, the quantity of Dynamic Milk within that vessel may be different, depending on the relative amounts of noise and clipping that accompanies it. So, lets say I have one particular 250 oz vessel which has 1 oz of noise (solids) and 49 oz of clipping (creme). That leaves me with 200 oz of Dynamic Volume in that Vessel. Whether you want to express that volume as a difference or a ratio doesn't really interest me. Now if I have 20 calves that each need to be bottle fed 10 oz of milk, I know I need 20 10oz bottles to carry my Dynamic Volume of milk. However, the Dynamic Volume from that vessel has not now become 20 bottles, it is still 200oz. Okay, enough of my nonsense. Todd Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: film scanner
That is great news! Could we ask that you post a note here when it is available. Thanks very much Brad On 8/29/02 5:02 AM, Kapetanakis, Constantine [EMAIL PROTECTED] wrote: There will be OS X support for the Polaroid scanners. We are currently in testing. -Original Message- From: Arthur Entlich [mailto:[EMAIL PROTECTED]] Sent: Thursday, August 29, 2002 3:05 AM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: film scanner I forgot to mention that the current dust and scratch filter from Polaroid is not written for the Mac, only the PC. The program is a nice extra, but not required. Art Brad Smith wrote: I have this scanner on a Mac/Firewire. A number of others on this list also have it. In general, we're a happy bunch of scanners, and I don't remember anyone who has one ever said they wish they'd have purchased anything else. Downside on the mac is that it doesn't run under OS X. I run it under 9.2. And you should note that I didn't say that I run it under Classic Mode. I've not been able to get that to work since I upgraded to OS X and classic. So I just keep my old Sys 9.2 on a separate partition and boot from it when I want to scan. I've only used Polaroid Insight scanning software, so I can't comment on using other scanning software. I'm very happy. Brad Smith Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
