[filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE!
You may use other filters but must be able to correlate to a film density. This correlation is not linear and will be different for each scanner. The problem arises from the fact that a densitotemeter reads densities differently than a scanner. A densitometer captures all light passing through the media under test, while a scanner captures light entering through its lens aperture. -Original Message- From: Clark Guy [mailto:[EMAIL PROTECTED]] Sent: Thursday, August 08, 2002 3:08 PM To: [EMAIL PROTECTED] Subject: [filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE! HI, Constantine! You are correct that if one adds uncontrolled light scattering into the mix of variables, one can obtain less reliablie results than if one eliminates it. I (for the purposes of discussion) chose to ignore scattering. In my tests at my old employers' labs, we used high quality glass filters, and later, when verifying the operation of our devices, we used high purity distilled water (in highly polished quartz cuvettes) with the appropriate dyes to minimize the effects of scattering. If a standard were created mandating the use of some particular type of filter set for scanner testing, all of you would be using the same standard, and your numbers would be comparable. I still maintain that this can be done, and at miniscule cost to the manufacturers of scanners. (compared to your advertising budgets, that is!) Guy -Original Message- From: Kapetanakis, Constantine [mailto:[EMAIL PROTECTED]] Sent: Thursday, August 08, 2002 1:49 PM To: Clark Guy Subject: [filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE! That is wrong. The light scattering characteristics of different media are different. If i am not mistaken that is called the Q-factor. Without elaborating much try this very simple experiment. Take two different media of similar densities, as measured with a densitometer i.e. a ccNeutral density filter and a gray scale target of either film or another base material. Scan both with the same scanner while disabling auto-exposure and you will get different results. 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: IV ED dynamic range... DYNAMIC RANGE!
Hi Toodd, Ouch. Sigh. Dynamic range: 1. The difference, in decibels, between the overload level and the minimum acceptable signal level in a system or transducer. snip 5. The difference between the maximum acceptable signal level and the minimum acceptable signal level. (Modern Dictionary of Electronics, 6th ed.) Austin is, of course, right on this one. I don't claim to know DyR better than anyone else but I have followed the discussion for some time. So, I'm not sure why what you cite above supports Austin any better than Julian. My reading of Julian is that he is in full agreement/compliance with what is written above. Possibly, but it depends on how it and the terms used are interpreted. I don't recall who believes what means what, but the terms CAN be ambiguous...and the ones cited certainly are. I believe he feels DyR is exactly: 5. The difference between the maximum acceptable signal level and the minimum acceptable signal level. (Modern Dictionary of Electronics, 6th ed.) Again, what does minimum acceptable signal level mean? Is that the minimum measurable change in signal, or the lowest voltage the signal can attain What does maximum acceptable signal level mean? The largest amplitude the signal can attain, or the highest voltage the signal can attain? My reading of Austin is that he believes DyR is the The difference between the maximum acceptable signal level and the minimum acceptable signal level, divided by noise, (where noise is typically/frequently specified as 10. It depends. Using the definitions above, and using what I believe the terms mean, I'll define the terms here... Per definition 5 (because it's easier and more to the point): maximum acceptable signal level means the largest amplitude. It is EXACTLY the same as the largest voltage the signal can attain, minus the minimum voltage the signal can attain. minimum acceptable signal level means the smallest amplitude that can be measured. Typically, this is noise. If that is the definition of those two terms, than #5 is correct. You can extrapolate those definitions to #1 if you like, and therefore it's correct too... What happens is people don't understand the CONCEPT of dynamic range, and therefore don't understand what the terms actually mean...and draw a different understanding as to what dynamic range is. Comment: this went back and forth interminably, and I think most of that could have been avoided by actually quoting standard definitions of the term and working from there. Just curious, would those standard definitions and terms BE what you quote above? If so, lets see if it makes a difference. I doubt it will... That's the point, there ARE no standard definitions and terms... Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: PS sharpening
Sharpening will not recover lost detail. It only creates an illusion of sharpness, and it is very easy to overdo, so beware. - Original Message - From: Alex Zabrovsky [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, August 08, 2002 23:53 Subject: [filmscanners] RE: PS sharpening Thanks, will look at it. The sharpening I meant originally is intended to be implied on GEMed images with high setting such as 3 and 4, since there is obvious sharpness impact at this GEM settings. Otherwise, I don't sharpen either. Regards, Alex Z -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Maris V. Lidaka Sr. Sent: Wednesday, August 07, 2002 6:20 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: PS sharpening Most people don't sharpen immediately after the scan (though some have suggested an immediate MINOR sharpening to remove artifacts introduced by the scanning process), so at 2900 dpi and 1000 dpi don't sharpen. When you are done with the image and it's ready for print or the web, then you sharpen, and at that point it depends on the resolution of the image and it's content. I know of no set rules or guidelines. Bruce Fraser has some excellent articles on sharpening at http://www.creativepro.com/author/home/0,1819,40,00.html Maris - Original Message - From: Alex Zabrovsky [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Wednesday, August 07, 2002 11:55 AM Subject: [filmscanners] PS sharpening Hi. I would be interested to know how people use Unsharp Mask in PS to make the images sharper, especially following high settings of GEM (produced by Nikon IV ED) I'm still trying to establish the range of best Unsharp Mask settings for different cases (scenic, portraiture and other kinds). Let's assume the scanning resolution is 2900 dpi and 1000 dpi. Regards, Alex Z 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 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: IV ED dynamic range... DYNAMIC RANGE!
Peter, Some time ago you promised us a paper setting out your definition, derivations and sources. I HAVE provided definitions, clear, concise definitions. I have also clearly provided my assertions etc. I said I would write-up something, I never made any PROMISE to do so, nor stated any time frame for doing so. Until you do this and circulate it, off forum, to those of us who offered to do a peer review I suggest you keep quiet. I find your request unquestionably arrogant and completely out of line. I'll discuss what I want, within the guidelines of this newsgroup. I don't want to get into a further debate until you verify your assertions. I don't need to verify anything on this subject. What the purpose of my proposed paper was, was simply to provide all the information that I have already posted on this subject, as well as any other information I may have, plus possibly some diagrams explaining concepts further. As you somehow believe there is something wrong with my understanding of dynamic range (which I know are correct, and the ISO spec backs up my understanding as well), I suggest it is you who should verify his assertions. Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: IV ED dynamic range
As far as I remember, theoretical dynamic range's maximum is 4.0 which is ideal ... There is no theoretical limit to dynamic range. It's like a Richter or decibel scale, open-ended in one direction. There IS a theoretical limit to DENSITY range, which is what you mean when talking about what you're talking about: 6000°C black body (solar photosphere temp) emits about 3.405E25 photons/sec/ster/m^2 between 400 and 750nm. 25°C black body is around 3.884E-3 photons/sec/ster/m^2. It is possible to get brighter surfaces, but the UV content would be a problem for the sensor, and it is possible to run the scanner colder, so getting a lower thermal black emission, but these are probably beyond practical limits anyway. Assuming a light source area of approximately 1000th area of the film surface, being totally focused onto the film area, and black emission from the film surface, that results in a contrast equivalent to a dMax of 25. Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: IV ED dynamic range... DYNAMIC RANGE!
I would agree with your comments IF: 1) indeed the competitors spec usage could be PROVEN to be in opposition to either standard practice or was indeed a misuse of terms. Based upon the discussion which occurred here recently regarding the use of density range, dynamic range, etc., it seems fairly hopeless. Partially speaking, this is because there have not been agreed upon definitions or standards within the industry. 2) the cost of the educative process would be shared among the players within the industry There is more than one way to damage a competitor. You can indeed play with the numbers to make your product spec out better and not play by the same rules as you competitors, or you can goad your competitor to spend their advertising budget on trying to prove that their competition is being dishonest... Individual companies lose when they try to prove someone else in their industry is being dishonest, and that is why you almost NEVER see these types of advertising campaigns used and even less often are they successful. And law suits are usually equally unsuccessful, again because the terms are intentionally slippery enough so no one is actually lying. It ends up sounding like sour grapes, and the correct party is often more damaged by it than helped. In almost every case where the public was educated in these matters it was done through either neutral third parties, or by institutes which are specifically developed (and financed by a whole industry sector) to standardize specs because chaos ensured and the public was ignoring all stats and specs, since none could necessarily be trusted to be meaningful. Art Clark Guy wrote: HI, Constantine! I disagree--- if the competition insists on using bogus specs, you should stay above that, and point out the fact that the competitor's specs ARE bogus, and why. Educate the consumer, don't try to BS us! It's been tried before by all sorts of industries, with generally bad outcomes in the long term. (look at the High Fidelity Audio community for example!) Thanx! Guy Clark -Original Message- From: Kapetanakis, Constantine [mailto:[EMAIL PROTECTED]] Sent: Thursday, August 08, 2002 9:58 AM To: Clark Guy Subject: [filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE! You are right. The max optical density of our ss120 scanner as an example is about 3.6~3.7. We measure this we a slide we made in house on Velvia film. Each step on the gray scale is .1 density units different and we look at the point of clipping as the maximum density. However, when Nikon starts advertising theoretical maximums of 4.2 ( 14 bits) then we have to start advertising the same way. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE!
Hi Arthur, Based upon the discussion which occurred here recently regarding the use of density range, dynamic range, etc., it seems fairly hopeless. Partially speaking, this is because there have not been agreed upon definitions or standards within the industry. Actually, that's not true. They are VERY standard within certain specific engineering areas...unfortunately, it's marketing, and people who don't understand (and not all engineers...and people who have an engineering title but aren't really engineers...understand this...) this... I believe the term density range is quite strait forward...but I must admit, the term dynamic range sounds a lot cooler ;-) Regards, Austin Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Help with purchasing decision?
Thanks for this site Erik. I'm not sure what to make of these no-name reviews. Can you tell us who's behind the site and where they're coming from? It's less important, but I was disappointed in the Polaroid review because it's now so dated. Maybe they all are. Sam Hi! This site has a lot of info: http://www.imaging-resource.com/SCAN1.HTM Regards Erik Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: PS sharpening
Yes it will be downsampled. To downsample by 2, one method would be to change the dimensions of the image to what you want, but UNCHECK Resample Image Click OK. This will change the resolution but will not be downsampled yet. Then Image - Image Size - change the resolution to 1/2 of the Resolution shown, readjust the Document Size to what you want, click OK. It will be downsampled by 1/2. Continue doing this until the Resolution is what you desire. Maris - Original Message - From: Brian [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, August 08, 2002 4:49 PM Subject: [filmscanners] Re: PS sharpening Anthony, I would like to ask you a question about the proper interpretation of downsampling. If I scan a 35 mm slide or negative at 4000 dpi in a Nikon Coolscan 4000 and I want to make a print in Photoshop, I alter the long dimension to 11 inches (the short dimension ends up at whatever to retain the proper dimensions). Since this usually ends up in a file size that is smaller than what it was originally, does this mean the image will be downsampled? If the answer is yes then how do I downsample in powers of 2? do I go 4000 to 2000 to 1000 to 500 to 360, sharpening at each step as you suggest? [remainder snipped] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE!
Austin, I really don't want to dance, so I am not going to get into the he said, she said thing I am going to stick by my interpretation of what was said and how each of you has interpreted it. For now, I am not concerned with the maximum acceptable signal, given that I understand everyone's interpretation of this to be the maximum amplitude short of flat line saturation (concept mine). I do not think anyone but possibly me is thinking in absolute terms of theoretically possible maximum amplitude of the signal beyond stauration, which may be unreadable or unmeasurable. I think in everone's practical case the notion of full saturation is the limiting case for maximum accpetible signal. However, turning to minimum acceptible signal, if I understand you, you are holding that theoretically the dMax-dMin range is much broader than the dynamic range whose lower limit is limited by the base noise level and whose upper limit is limited by the flat line saturation level. In other words, the dynamic range is the readable range (a subset within the full dMax-dMin range) where the full range can theoretically extend beyond the dynamic range such that they may or may not be synonomous or identical. Julian, if I read him correctly seeks to define the dMax-dMin range as being that which already accounts for the base noise on the lower dMin end and the full saturation level on the dMax end; thus he is implicitly accounting for the basic noise level without making it an explicit part of the equation. Thus, his definition of dynamic range is the readable or measurable range and for all practical purposes identical to the dMax-dMin range. The phrases, ...in one scan. It is the instantaneous range the scanner can handle, I take to be throw away phrases where he is for purposes of simplicity and consistency with how specs are typically derived trying to eliminate the possibility that multiple passes could very well alte5r and extend the dynamic range by lowering the basic noise level on average. Thus, I hear both you saying basically the same thing but in slightly different words that include and exclude elements in definitions by assuption and stipulation. If I am wrong in my understanding of each or both of you, then I do not have the foggest idea what is being said and havve to figure that you are both crazy, leaving me the only sane one in the asylum. The King of Hearts always said that it was the rational sane world of engineers that were the crazy ones with the only sane ones being locked away in the asylum. When we get done all the word games, we will find that we are all engaged in merely an ecology of games that impact on each other but are separate and distinct games that we are playing with ourselves such that we are all two steps short of a twelve step table. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Austin Franklin Sent: Thursday, August 08, 2002 4:27 PM To: [EMAIL PROTECTED] Subject: [filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE! Hi Laurie, The whole damn thing turns on the phrase, acceptable signal level. Austin, if I read him correctly, holds that acceptability is defined as being above the noise level at the low end; If you read the definitions used, both terms used acceptable signal level. When used as minimum, it, to me, means noise, when used as maximum, it mean the maximum amplitude of the signal (before clipping, or saturating or whatever...where the signal is still valid). Julian probably implicitly accepts this also. I do not believe this. What others, who do not believe my understanding of dynamic range, believe is that dynamic range is not based on noise, but on the largest value of density the device can detect, minus the smallest density value the device can detect, basically, dMax - dMin, and there is no noise in the equation... This is simply the density range, and is not the dynamic range. Here is what he said: DYNAMIC RANGE on the other hand, is the smaller range within the Density Range that the scanner can capture AT ONE TIME i.e. dynamically i.e in one scan. It is the instantaneous range the scanner can handle. Which, of course, has nothing to do with what I believe dynamic range is. Austin 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: IV ED dynamic range... DYNAMIC RANGE!
Arthur Entlich wrote: Partially speaking, this is because there have not been agreed upon ^^ definitions or standards within the industry. That was supposed to read Practically speaking... Art Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: IV ED dynamic range... DYNAMIC RANGE!
I am only posting two replies to what has been posted during my overnight. This one is a short response to the nitty gritty of Austin's argument. The other includes replies in a single post to other points by everybody. There are two points I am addressing in this post: 1. Dynamic range is a range, not a resolution 2. Dynamic range is the range that the scanner can capture AT ONE TIME i.e. dynamically i.e in one scan I address them purely by providing the resource that Austin requests. For logical discussion, see other posts. 1. Dynamic range is a range, not a resolution * Julian: It is a simple enough concept. Most explicitly, dynamic RANGE is ***not*** the RESOLUTION, Austin: Yes it absolutely is. Julian: and there is no book or standard that has ever said this. Austin: Well, the ISO spec shows clearly it is exactly what I've said it is, as well as every other resource I've posted on this subject before. I simply don't understand where you get the resources for your misguided understanding of it. YOU HAVE NO RESOURCES THAT SUPPORT YOUR BELIEF. Julian now replies: Hmmm. Here is the draft ISO spec, from http://www.pima.net/standards/iso/tc42/wg18/WG18_POW.htm . It is entitled Photography Electronic scanners for photographic images Dynamic range measurements. Perhaps there is another ISO spec from which you are deriving your beliefs? Perhaps you could post it? ---direct quote from Proposed ISO standard--- 7.2 Scanner dynamic range The dynamic range is calculated from the Scanner OECF by: DR = Dmax - Dmin(7.2) DR = Scanner Dynamic Range Dmax = Density where the Signal to noise ratio is 1 Dmin = Minimum density where the output signal of the luminance OECF appears to be unclipped ---end quote from Proposed ISO standard--- (and OECF is opto-electronic conversion function) You will notice, it is exactly as I have described it, a RANGE. It is the range between Dmax and Dmin. It is not a resolution, there is no mention of resolution. Can you tell me then how this says that Dynamic Range is a resolution? 2. Dynamic range is the range that the scanner can capture AT ONE TIME Julian: DYNAMIC RANGE on the other hand, is the smaller range within the Density Range that the scanner can capture AT ONE TIME i.e. dynamically i.e in one scan. It is the instantaneous range the scanner can handle. Austin: Absolutely not correct. Where on earth did you get that? Please please provide any credible source that says anything to the such. The ISO spec doesn't define dynamic range that way...nor do any of the resources I have seen. On the contrary, the ISO standard states a fairly precise process in which the Dynamic Range is measured by scanning a single slide in a single pass. (They do repeat the same single-scan measurement several times to improve accuracy). Here is the relevant text, remembering that the dynamic range is calculated from the OECF: quote from proposed standard 6 Measuring the Scanner OECF The scanner OECF shall be calculated from values determined from a test chart 4 that consists of a density range higher than the range the scanner is expected to be able to reproduce. For reflective targets the density range shall be higher than the range of typical reflective media scanned on this scanner. Many scanners will automatically adapt to the dynamic range of the scene as reproduced on the film or reflective media and the luminance distribution of the film. The results may also differ if the scan mode is grey scale or RGB A minimum of 10 trials shall be conducted for each scanner OECF determination. A trial shall consist of one scan of the test chart. For each trial, the digital output level shall be determined from a 64 by 64 1 pixel area located at the same relative position in each patch. Identical, non-aligned patches may be averaged, or the patch with the least scanning artifacts, such as dust or scan lines, may be used. The scanner OECF so determined shall be used to calculate the resolution measurements for this trial. If the scanner OECF is reported, the final digital output level data presented for each step density shall be the mean of the digital output levels for all the trials 6.1 Scanner settings The scans for the determination of the scanner OECF shall be made in RGB or grey scale mode with a resolution set to the maximum sample frequency (given in Dpi or Ppi) divided by an integer to avoid interpolation R = Rmax / i R = scanning resolution Rmax = maximum scanning resolution of the scanner i = integer value (6.1) The scanner shall be set to automatic adaptation to the dynamic range and the digital values representing the dark grey patches shall be
[filmscanners] Re: IV ED dynamic range... DYNAMIC RANGE!
Julian Robinson [EMAIL PROTECTED] wrote: 1. Dynamic range is a range, not a resolution No, it's a ratio; a value measured in dB. As such, it implies a resolution, namely the number of divisions it makes sense to divide (quantize) the range into. 2. Dynamic range is the range that the scanner can capture AT ONE TIME i.e. dynamically i.e in one scan No. Dynamic here is meaning 4. in Random House 4. of or pertaining to the range of volume of musical sound. Dynamic ranges are basically volume measurements; that is, a dynamic range is a ratio of volumes, loudnesses, or, more generally, signal amplitudes. 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: [filmscanners_Digest] filmscanners Digest for Fri 9 Aug,2002-Firnware
What is firmware? TH -=-=-=-=-=-==-=-=-=- Date: Thu, 08 Aug 2002 01:44:55 -0700 From: Arthur Entlich [EMAIL PROTECTED] Hi Michael, Welcome to the list. I can give you some views in regard to your purchase. I use both a Polaroid S4000+, which is the identical hardware in the Microtek 4000tf with different firmware and front end software, and I also own a Minolta Dual Scan II, which is very similar to the Elite II. The main difference between the Dual II and the Elite II are: Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: [filmscanners_Digest] filmscanners Digest for Fri 9 Aug,2002-Firnware
TH, Firmware is the software that is running inside the scanner to make the scanner run. It controls all the internal stuff like steper motor, light source, etc. From a user's point of view the firmware is usually not important unless you need some bug fixes. Rob -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Khor Tong Hong Sent: Thursday, August 08, 2002 10:38 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: [filmscanners_Digest] filmscanners Digest for Fri 9 Aug,2002-Firnware What is firmware? TH -=-=-=-=-=-==-=-=-=- Date: Thu, 08 Aug 2002 01:44:55 -0700 From: Arthur Entlich [EMAIL PROTECTED] Hi Michael, Welcome to the list. I can give you some views in regard to your purchase. I use both a Polaroid S4000+, which is the identical hardware in the Microtek 4000tf with different firmware and front end software, and I also own a Minolta Dual Scan II, which is very similar to the Elite II. The main difference between the Dual II and the Elite II are: -- -- 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: IV ED dynamic range... DYNAMIC RANGE!
This is composed into a single post because I know that this topic is overexposed and frustrates many people. It frustrates me too, but it would be wrong not to try to correct misinformation which is propagated with such authority that it has succeeded in hijacking the moral and technical high ground on this authoritative list. The purpose of this list is to allow all of us to discuss and get a handle on exactly this kind of question. I know that Austin has a deserved great reputation amongst list members, partly because he is a prolific and unflagging contributor and has obvious technical knowledge. Just the same, for whatever reasons, the view he puts forward on dynamic range is not in accord with any textbook, paper or standard of which I am aware, and this definition misleads and distorts and confuses much consequential discussion. Worse than that, it has succeeded in stifling a lot of the useful discussion we should be having on a pretty basic topic because people have realised they don't understand this most basic aspect of scanning - in large part because they are confused by unnecessarily difficult and incorrect constructions of what dynamic range is. For those of you who have assumed that Austin's view is correct and therefore not attempted to read my earlier post in any detail - I beg you, please read what I wrote (first post headed RE: IV ED dynamic range... DYNAMIC RANGE!) and try to follow the logic of it, don't just assume that any particular person has the natural authority here. I tried hard to make this post short-ish and non-engineering. If it makes any difference to you, I have at least as much experience with using Dynamic Range in my career as Austin so don't make any assumptions about level of knowledge based on presentation or style. Go and look at every definition of dynamic range you can find for yourself on the web or in textbooks - you will not find one which says that dynamic range is a resolution. It is a range. Answers to many posts below: At 23:06 08/08/02, Austin wrote: DYNAMIC RANGE on the other hand, is the smaller range within the Density Range that the scanner can capture AT ONE TIME i.e. dynamically i.e in one scan. It is the instantaneous range the scanner can handle. Absolutely not correct. Where on earth did you get that? Please please provide any credible source that says anything to the such. The ISO spec doesn't define dynamic range that way...nor do any of the resources I have seen. Austin - in my other post you'll see that the draft ISO spec does support my assertion. You need to get over this mental block as to what the dynamic means in dynamic range. Here is another very simple example to illustrate the distinction between Dynamic Range and the non-dynamic kind of range - a very simple distinction that people need to understand. Consider a basic analog 3-range voltmeter. It has a graduated scale, a needle, and you can switch between 3 ranges, 1v, 10V, 1000V. We can measure on this meter from max = full scale deflection, down to a min = the smallest graduation on the scale (let's say). The meter is divided into 100 graduations, this is equivalent to saying the *resolution* is 1/100th of full scale. So, on the 1V range we can measure from 0,01V to 1V. On the 10V range we can measure from 0.1V to 10V. On the 1000V range we can measure from 10V to 1000V. The Dynamic Range of this meter is max/min = 100 in each case. BUT, and here is the rub, this meter can - overall - measure voltages from 0.01V to 1000V. This is the total range or just the range, the kind or range we talk about without the word dynamic in front of it. In this example, the range is 1000/0.01 = 100,000 to 1. So for this meter: total range = 100,000:1, and dynamic range = 100:1 Engineers might say that total range = 100dBV and dynamic range = 40dBV. The difference between these two figures is EXACTLY analogous to the difference between the Dynamic Range and Density Range of a scanner. Dynamic refers to at one instant, it means the signal range of the thing without changing it's configuration. Same in radio, same in audio, same in signal theory, same in light. Notice that in above example the resolution is 1/100th of full scale. You could express this resolution if you wanted to as a number of distinguishable levels, i.e. 100. The number of distinguishable levels (i.e. loosely, the resolution) is the same *number* as the Dynamic Range. But they are not the same thing! And under different assumptions even the numbers would not be the same. More on that below. Absolutely incorrect. Dynamic range is absolutely NOT a range as you believe it is. It is what happens WITHIN A RANGE...or it would not contain the word dynamic. You are arguing against everything I have ever seen written... please save us from going on for days on this in hopeless spirals - just post your authoritative sources to support this. A range is simply a range. I'll repeat that
[filmscanners] RE: PS sharpening
-Original Message- From: [EMAIL PROTECTED] Then Image - Image Size - change the resolution to 1/2 of the Resolution shown, readjust the Document Size to what you want, click OK. It will be downsampled by 1/2. Continue doing this until the Resolution is what you desire. Excuse my ignorance but what is the logic doing it this way instead of resample it directly to the resolution you want? Rob Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
