[filmscanners] RE: Dynamic range/ Roy's first post to the max-noise list, LONG
I thought to post this yesterday, but decided not to because much of it is redundant to what has been discussed here lately, and it is long. However, I've decided to post it now because Roy cites some DyR definitions from audio that I think will help us move away from the fixation of bits that seems to inexorably dominate when discussing scanners, even though we all agree they are only a function of the digitization of a DyR. (I find it fascinating how much we all agree on this then find a way to discuss it again and again as though each time it were it were fresh and illuminating. I'm convinced that NOT discussing bits is the key to moving this conversation forward). One last thing, we are all getting frustrated by the redundancy, but I'm not convinced it's time to give up just yet. So, I'd like to advocate that those of us who do choose to continue, try to keep it cool and cordial. If anyone finds Roy's tone provocative at any point please remember this was written in another place and time. This was Roy's first post to the max-noise list: on 7/4/02 1:57 PM, Roy Harrington wrote: Greetings All! Since some of you may not know who I am, let's just say I am a concerned participant in the issue of Dynamic Range. To date I've witnessed three separate large discussion/ arguments about it with many hundreds of posts. I was out of town for the latest one in the filmscanners group. I was an active participant in the previous one in the digital BW yahoo group and saw the tail end of one in the piezo BW yahoo group. In all three cases the argument finally died leaving the participants totally frustrated and most of the other group members very alienated. None of the discussions resulted in an agreed upon resolution. In this writing, my desire is to attempt to resolve this issue and forego future non-productive arguments. I'm determined not to get into battle of Yes it is -- No its not. This may be a difficult task but I feel compelled to at least try. So here goes nothing :) What I notice most about much of the discussion in the incessant wandering of what the heck we're talking or arguing about. Its all based on Dynamic Range but whether its audio, video, scanners, imaging, signal processing, volt meters, etc. keeps the discussion from focusing on anything in particular. I'd like to start off with a very specific reference and situation. The reference that was introduced by Austin and referenced repeatedly is Higgins book Digital Signal Processing in VLSI. I think everyone is comfortable with this text and agrees with what is stated in it. The section of interest is: 1.4.1 Dynamic Range Example: Analog Vs Digital Audio (I.e. this is mainly written with audio in mind and I'd like to stay fixed in that context for now. The both analog digital are intertwined here but we can concentrate on the analog). The equation of interest is: DynamicRange (db) = 20*log10 (largest/smallest discernible signal) with signals expressed in voltage or current. there's a footnote: decibel is defined as 10*log10(power ratio) power versus voltage accounts for the extra power of 2. The picture he shows is labeled as an analog vinyl record groove: http://www.darkroom.com/Images/DynamicRange01.jpg Austin's Statement Here's Austin's statement about the text and diagram: Austin wrote: Reference this diagram: http://www.darkroom.com/Images/DynamicRange01.jpg largest is shown on this diagram to be the maximum signal level minus the minimum signal level, and is the largest range or absolute range that the signal can go from = to. Example, maximum signal level is 5, minimum signal level is 2, the absolute range/largest range is (5 - 2) or 3. smallest is shown as the noise. It is the same thing as smallest discernable signal, which means the smallest change that can be detected. Where the signal is at it's lowest point, is what I am calling minimum signal level. Where the signal is at it's highest point, is what I am calling maximum signal level. The dynamic range equation is, using these terms, and the provided diagram, can be either of the following: DR (dB) = 10log10 (largest/smallest) DR (dB) = 10log10 ((maximum signal level - minimum signal level) / smallest) You can substitute smallest DISCERNABLE signal for smallest in these equations. Do NOT confuse smallest/smallest discernable signal with minimum signal level, they are not the same thing, though in some circumstances they MAY have the same value. First of all I'd like to commend Austin for his explicit statement of this interpretation of the Higgins text. Its too bad that Higgins wasn't as explicit about what he meant when he wrote the book. As the scan of the diagram shows, the labeling of the diagram is fairly spare. I'm quite sure that this is NOT the interpretation that Higgins had in mind while writing the book. I'd like to be equally explicit about
[filmscanners] Re: Dynamic range
Austin wrote: Reference this diagram: http://www.darkroom.com/Images/DynamicRange01.jpg largest is shown on this diagram to be the maximum signal level minus the minimum signal level, and is the largest range or absolute range that the signal can go from = to. Example, maximum signal level is 5, minimum signal level is 2, the absolute range/largest range is (5 - 2) or 3. Hi Austin, Above is the part of your explanation I don't have the background to understand. What type of signal will have a max signal level of 5 and a min signal level of 2? I understand that some signals may be +/-3v, or something like that, but are there really signals that are +5-2? If we are feeding a range of signal levels through a device to determine the device's DyR, isn't it done in a way that starts with a signal of zero, or so close to zero as to surely be below the noise of the device? Then progressively stronger signals are fed till we can determine what signal strength becomes just distinguishable from noise, which tells us the devices MDS? Then progressively stronger signals till we see at what point the signal is no longer distinguishable from clipping/distortion? Isn't this point of clipping/distortion what the Analog Devices white paper uses for it's Peak Level? See again, sec 3.1 fig 5. They show peak level as a point, not a range: http://www.analog.com/library/whitepapers/dsp/32bit_wa.html#3 So by feeding a range of signal levels we determine the TWO values we need for our short-form DyR equation, max and min: max/min, or max - min? I'm having trouble to imagine the scenario where one has a device that produces a Largest/Peak Level/Dmin of 5-2, but I accept that is due to my lack of understanding. Please explain. This gets to my comparison of the Higgins diagram to fig 5, which you dismissed because One diagram is in log (the paper), and one is in non-log (Higgins). You can not compare the two. I take issue with that, those are mathematical differences, but I'm discussing this conceptually and via the terms of the definition, and how the diagrams illustrate those terms. Todd smallest is shown as the noise. It is the same thing as smallest discernable signal, which means the smallest change that can be detected. Where the signal is at it's lowest point, is what I am calling minimum signal level. Where the signal is at it's highest point, is what I am calling maximum signal level. The dynamic range equation is, using these terms, and the provided diagram, can be either of the following: DR (dB) = 10log10 (largest/smallest) DR (dB) = 10log10 ((maximum signal level - minimum signal level) / smallest) You can substitute smallest DISCERNABLE signal for smallest in these equations. Do NOT confuse smallest/smallest discernable signal with minimum signal level, they are not the same thing, though in some circumstances they MAY have the same value. 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 This sounds like an amazingly lucid explanation. Thanks for clarifying that. I know I've looked at a lot of audio references and have yet to see a density range specification within them. Electrical components just don't seem to have density ranges, they have dynamic ranges, which is a description of the range of power levels they can reproduce cleanly. Things that block or reflect light have density ranges, and a scanner's DyR is a quantification of the density range it can READ, but electronics in and of themselves just don't have density ranges. Is it fair to say that any item that LITERALLY has a density range can not LITERALLY have a dynamic range, and vice versa? I'd think so! I'd think an item could have a density range and a resolution, or a dynamic range and a resolution, but it can't have a dynamic range and a density range and a resolution... Todd At 14:53 30/08/02, David wrote: Does that mean you claim that density range and dynamic range are equivalent measurements of the same physical quantity? Well yes and no. Density range is normally a property of a slide or piece of film, or an image on a film. Dynamic range is normally a property of some processing device, like a scanner in this case. If you have a slide that can just be scanned by a scanner without the scanner saturating or getting the black bits lost in the noise, then the slide's density range is the same as the scanner dynamic range, in that case. A scanner doesn't have a density range, but it has a range of densities that it can handle. The maximum range of densities that it can handle in a single pass is its dynamic range. The maximum range of densities that it can handle under any circumstances is it's static range, or max range, sometimes called just Dmax by manufacturers. (Inaccurately, but we think we know what they mean. Dmax is not a range, it is a figure. When they say this, they are by implication assuming an upper limit of 0dB as the other end of the range). So if a slide's density range is greater than the scanner dynamic range then the scanner cannot capture the whole density range of the slide. I am using the terms as they are normally used. Both are measures of range of densities. One is the range of densities actually or potentially on a slide, one is the range of densities that a scanner can handle. You *can* talk about the dynamic range of a particular slide and be kind of correct. Or you could talk about the dynamic range of the medium (that is, the particular film). Dynamic range is, as it always has been, nothing more than the range of largest signal to smallest signal, usually expressed as a ratio. On an actual slide it is easy enough to pick the largest signal (the lightest density) and the smallest signal (the densest area which is just discernable against unexposed film background). For the medium, the relevant figures are the lowest POSSIBLE density, and the highest POSSIBLE density that can still be discerned from background black. If you use the language this way, then the slide's dynamic range is the same thing as its density range. Julian Julian Robinson Canberra, Australia http://members.austarmetro.com.au/~julian/ 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/ Roy's first post to the max-noise list, LONG
Gee, thanks Todd. One last thing, we are all getting frustrated by the redundancy, Sigh...yes. This was Roy's first post to the max-noise list: And I want to note, that I never saw this post, as I was not a participant in this list...choosing family time and vacation over arguing about this...but it appears to be a direct response to only my comments made on other lists...so, I, unfortunately, believe it is necessary to correct whatever misunderstandings or mis-statements have been made here. http://www.darkroom.com/Images/DynamicRange01.jpg First of all I'd like to commend Austin for his explicit statement of this interpretation of the Higgins text. Its too bad that Higgins wasn't as explicit about what he meant when he wrote the book. Higgins WAS explicit, VERY explicit in fact. There are only TWO terms used in the accompanying equation: DR = 20log10(largest/smallest discernable signal) So, we ONLY need definitions for the terms largest, and that is CLEARLY labeled on the diagram as: largest is shown on this diagram to be the maximum signal level minus the minimum signal level, and is the largest range or absolute range that the signal can go from = to. and: smallest is shown as the noise. It is the same thing as smallest discernable signal, which means the smallest change that can be detected. Note that the ONLY reference to smallest... in any of the text, IS smallest discernable signal, so there is NO question that smallest discernable signal and the smallest listed on the accompanying diagram mean the same thing, simply the diagram labeling was shortened. As the scan of the diagram shows, the labeling of the diagram is fairly spare. So what if it's labeled sparsely? There are only two terms it's showing here, and those are the only two terms used in the accompanying dynamic range equation, so no more labeling is required. The book is explicit in using the two terms, largest and smallest, and the diagram IS explicit in their meaning. Anything more would be superfluous. I'm quite sure that this is NOT the interpretation that Higgins had in mind while writing the book. It is EXACTLY what he meant, and there is NO interpretation required at all. Largest and smallest are CLEARLY shown as to what they are. These terms, when left undefined, CAN be ambiguous, but in the Higgins book/equation/diagram, there is NO ambiguity at all. I'd like to be equally explicit about the correct interpretation with supporting logic behind it. Oh, my hero! --- Interpretation of Higgins text. I'll begin with the fact that we're talking audio here. An audio signal is a wave form not a single DC voltage. When you measure the size of an audio signal what you measure is the amplitude of the wave form. In the left half of the diagram we see an audio signal that spans the whole record groove, the label largest is the amplitude of the largest possible wave form i.e. amplitude of the largest possible signal Funny, that's exactly what I have always said, and say above. I'll show it again here for clarity: ...and is the largest range or absolute range that the signal can go from = to largest range and absolute range... are EXACTLY the same as amplitude. ...or maximum audio signal. Well, that's an ambiguous term. Maximum as referenced to what? The right half of the diagram shows a very small audio signal amplitude. This term smallest or smallest discernible signal denotes the amplitude of the smallest audio signal (a wave form) that is discernible above the noise level. That's fine, and doesn't disagree or negate what I've said at all. This might also be called the minimum audio signal. That's ambiguous, just like maximum is. Minimum as in what, lowest signal level, or smallest discernable signal anywhere in the range as limited by noise? So the ratio that you end up with is: (amplitude of the max signal) / (amplitude of the min signal) or in totality: DynamicRange (db) = 20*log10((amplitude of the max signal) / (amplitude of the min signal)) with audio signal measured in voltage. But that depends on what you mean by min. If by min, you simply mean smallest discernable signal, that is correct, and is in agreement with exactly what I've always said. You haven't corrected ANY of my definitions or understandings, so I fail to see your actual point here. What this gives you is simply the range of audio signal levels where the audio system is operating within spec. The dynamic range spec number does not indicate ANY range whatsoever. It characterizes a signal OVER a range based on noise. Operating within spec has nothing to do with anything in this discussion. In layman words, this is the definition of dynamic range -- the range of audio output from softest to loudest. No, it is not the RANGE of audio output. It is characterized OVER a particular range, but does not denote any particular
[filmscanners] Re: Dynamic range
Austin, I have never read whatever paper you are talking about, but I GUARANTEE you it does not SAY that dynamic range is a resolution. I am sure that you, Austin, INTERPRET it to say that, but it will not actually say that. You probably should have read the paper before commenting... But no, that is the point. I don't need to because I know that no paper will say what you believe - you are mistaken in this and still, to this date, after buckets of wasted electrons and keyboard hours, you have still not produced a single reference that says what you say. I gave you this totally unsupported challenge as a free kick - you had absolutely every chance to smother me in extracts from this paper that I have not even looked at with quotes that agree with you. The fact that you have not done so I think proves the point. ... Austin, if you have a scanner with a noise level of 36dB below the max signal (i.e. 3.6D or 1/4096), No, where did you get 3.6D??? You can't equate DENSITY values with DYNAMIC RANGE. Density values are absolute things, like volts are, though density units are expressed in log form. They are NOT relative to noise. Good grief Austin, you are playing semantics. I only included the 3.6D to stop you from having a go at me for using dB in an area that usually we use Bels. I should have said Bels, except no-one understands what they are. Forget the D, I wasn't referring to density absolute, I was using it as the Bel version of 36dB. You have used this semantic and unrelated approximation of mine as your only argument below. It is not relevant, I do understand what D is about, I was trying to protect myself and readers from another of your interminable side branches designed to get you off the topic. I am sure you'd agree that you need a 12 bit downstream system to maximise the utility of this scanner. (because 12 bits digitises to 4096 levels, and one level is then just equal to the noise level of 1/4096 * max signal. You won't have wasted bits being lost below the noise, and you won't waste good information by failing to digitise the smallest possible discernable signal) That's correct, but don't confuse density values with dynamic range. Call this Case 0. ***The dynamic range is 36dB. I say that is the RANGE of this scanner, you say it is the RESOLUTION. In this case it is both. ***So, resolution also = 36dB. Well, no. As I've said, you are confusing density values with dynamic range. Now that I've removed the D equivalent, can you make a substantive comment on the point that was being made? CASE 1 Now, if this same scanner only had a 10-bit downstream system (such as from the old days when A/D's were incredibly expensive), what is the dynamic range? The noise level is 1/4096, and the smallest digital non-zero signal is one bit or 1/1024. Obviously the minimum usable or detectable signal cannot be smaller than either of these, or in other words it is the maximum or the two figures. In this case it is 1024, and the MDS is determined ONLY by the bit-size. Noise level is 4 times smaller than this, so is irrelevant. So DR is 1024:1 or 30dB or D3.0. The dynamic range IS 1024:1 or 30dB...but that has nothing to do with DENSITY values. I am not discussing density values. I am discussing dynamic range and only dynamic range as you know, so please reframe your response accordingly and stop this disingenuous nonsense. This scanner can, technically, still encode ANY range of DENSITY values into those 1024 available values. As you once said, duh! ***In this case DR = 30 dB ***Resolution is still 36dB if you stick with your formula = max/noise, or 30dB as it obviously is in fact, given you have a digital step size of 1/1024 or 30dB. Well, here you go again, Julian...and this is why I get pissy with you. You take things out of context and apply them to something else. I NEVER said the MDS was ALWAYS noise. In the case of the ORIGINAL SIGNAL, it is noise, in the case of the digitized signal, it is NOT noise. Well Austin, let me quote one of many interminable exchanges where I was tearing my hair out because you were insisting that MDS was noise. Please note carefully the contradiction, clear and unambiguous between these two statements: A) I NEVER said the MDS was ALWAYS noise. - from this post B1) The smallest discernable signal IS noise. - from post in June B2) This is a misunderstanding of the concept of dynamic range. It is ALWAYS based on noise. - post in June B3) Noise and smallest discernable signal are EXACTLY the same thing. - post in June. I have struggled for months to get you to agree that noise and MDS are not the same thing, and now you tell me you have always thought this!! I am pleased that you are coming round, but flabbergasted at the same time. Here is the exchange for the record so you don't accuse me of taking you out of context: --start of exchange last
[filmscanners] Re: Epson 2200 does it exist?
Frankly I want one now too, but it seems to me that the demand is so high that production quality could very well drop, so I am holding off for a awhile. -Joe 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, At 19:26 29/08/02, David wrote: 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. Yes, the number is a ratio. As I have said many times, this is because this is the ONLY way you can quantify a range in a single number so that the number is independent of irrelevant things. But the thing the ratio is measuring is a RANGE. It is measuring OVER a range, but it is NOT a range in and of it self. Just look at the equation, it is the biggest level divided by a littlest level. It measures the ratio of these two levels, that is it quantifies the range they represent, the range of which they are the endpoints, Yes, the two endpoints define the bounds of a range...BUT...that does not mean the result of this equation is also a range. The result is a characterization of one or more attributes of the inputs to the equation. The value of dynamic range says something more than the ratio of the two levels, it ALSO characterizes the number of discernable values. (I'll try and attach it. If it doesn't get through Tony's ISP's filters, go to http://www.analog.com/library/whitepapers/dsp/32bit_wa.html#3 . The diagram is Fig 5, about a quarter down the page). You can't get much clearer than this. The dynamic range is the range from the peak level (25dB) down to the noise floor (-65dB). It's simply an illustration showing where dynamic range is measured from. The RANGE it is showing has the endpoints at +25dB down to -65dB, THAT is the range, and the dynamic range is the result of those two numbers. It shows unambiguously the max level at the top of the arrow. It shows unambiguously the min discernable signal level at the bottom of the arrow. The arrow illustrates the range. The arrow DOES illustrate a range, and it points to TWO endpoints, but a range OVER which dynamic range is measured, it does not show dynamic range as a range. It is simply a diagram showing relative positions of log values. I have never heard dynamic range ever characterizes as the dynamic range. If dynamic range were a range, as you claim that diagram shows, then so would headroom and SNR be a range and they are not. I believe you are talking the term range here way out of context. Dynamic range is a single number. Because it is characterized OVER a range, does not make it A range. The dynamic range is the ratio of these two levels, or in logs since they have already done the work for us, 25-(-65)dB = 90dB. That's all there is to it, it is VERY straightforward. That does not make it a range. Simply saying 90dB does NOT illustrate a range. Saying 25dB to -65dB DOES illustrate a range. They are different. 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. The bit depth is one of the two things that might determine the minimum discernable signal of the scanner. If the smallest (one-bit) step is bigger than the noise level, then it will be the determinant of MDS. If not, the noise will be the determinant. Correct. As Todd says, bit depth may be material to the values you will measure. But it is not part of the definition. Who said it was? It MIGHT be in the formula if you know that it dominates the noise level in terms of determining MDS. In this case, your dynamic range formula would be DR = max signal / smallest step size. Otherwise the formula would be DR = max signal / noise level Correct, and I've always said exactly that, even though you seem to ignore that fact. 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... David, can you tell me why you have to include all these words like Can be seen as corresponding to ...? You don't need to be so convoluted, the reality is much simpler. Try this in place of your complex paragraph - In any dynamic range calculation, the maximum signal is itself. The noise defines the minimum recognizable signal level. The ratio of these is the dynamic range. That's true, but that doesn't negate what David said above at all. Much simpler, more accurate, It is not more accurate, both statements are equally as accurate in and of themselves. and agrees with the definition formulae. Well, so does David's
[filmscanners] Re: film scanner
Hi Costas, Does that mean the current Dust and scratch filter that Polaroid offers on its website for Polaroid scanner owners will be available for Mac owners too eventually? I know a number of SS120 and some SS4000 who would like to have that plug in for Adobe (and or the stand alone version). Art Kapetanakis, Constantine 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
[filmscanners] Re: Dynamic range -- word derivation
on 8/30/02 8:28 AM, Austin Franklin at [EMAIL PROTECTED] wrote: Roy, 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. I don't know if that is true or not, as I don't know who invented the characterization, or when it was invented...I am trying to find out. I take it, for you to make this as a statement of fact, you know the actual history of dynamic range? Who invented it? What's your earliest reference of dynamic range? Hi Austin, There are some words that are invented but by and large most English words come from way, way back. So for the word dynamic all the dictionaries I've looked at reference Old French and Greek. dynamo- means power or powerful. The word range has an awful lot of meanings including where the cows hang out and homes used to be :) But I suspect we can agree on the mathematics notion of a bounded set of values. I.e. there's a max and a min and all the values in between are in the range. So, when were the words put together? Since humans make sound more readily than they make light, the words were used as applied to sound first. For anyone who plays a musical instrument, the word dynamics has always been used to indicate how loud you are playing. A piece of music with lots of dynamics is one that has quiet sections and loud sections. Playing with dynamics means playing softly and loudly. An instrument has a range of dynamics based on how soft or loud it can be played. The piano was invented around 1600 specifically to have a keyboard instrument with a greater range of dynamics than the harpsichord. The name in fact was originally pianoforte which literally means soft/loud. The point is that the term dynamic range was coined and used in common language for a long time before there was a technical definition and formula. So the term was in common usage and the concept in place way before someone tried to calculate a value for it --- not a technical formula looking for a name and coining dynamic range. The best reference for dynamic range as applied to light is Ansel Adams book set The Negative in the chapter The Zone System. Here's my edition quote: The full range from black to white is represented by Zones 0 to X. Within this lies the dynamic range representing the first useful values above Zone 0 and below Zone X, or Zone I to IX. The range of zones which convey definite qualities of texture and the recognition of substance is the textural range from Zones II to VIII. There's also a diagram illustrating the above paragraph. I don't know when he first used these terms but he was teaching the Zone System in the 1940's. All of the above is consistent with the standard usage of the word range (i.e. values from a max to a min). Also dynamics meaning power is also consistent. A loudest sound is a max power and a quietest sound is a min power. Similarly a brightest light is a max power and a dimmest light is a min power. ...but you're just so damn prolific, and repeating the same thing...and it gets tiring and frustrating...with nothing (seemingly) new added. This post was short and easy, and quite to the point...which I'm happy to respond to. If you can keep the posts short, I'd be a lot happier. Regards, Austin Short is good, I hope that's short enough. Roy PS. At the risk of lengthening the post, the following is just references to the web. I don't think there's anything to respond to, since I didn't write them. Roy -- In my first post to max-noise that you didn't see, I cited lots of references to the use of the term dynamic range as applied to audio. If you just humor me and think range of power and read through the references, I don't see how you can miss the consistency of concept. I spent a short time searching for audio dynamic range with google. This is every definition of dynamic range that I found, not at all a select list: http://whatis.techtarget.com/definition/0,,sid9_gci213623,00.html Dynamic range describes the ratio of the softest sound to the loudest sound in a musical instrument or piece of electronic equipment. This ratio is measured in decibels (abbreviated as dB) units. http://www.epanorama.net/documents/audio/dynamic_range.html Dynamic range is the ratio of maximum undistorted signal (full-scale or onset of clipping) to residual noise (noise floor). Dynamic range in generally measured in decibels (dB). - http://georgegraham.com/compress.html dynamic range -- the difference in loudness between the loudest peak and the noise floor of your equipment. - http://www.electronic-projects.net/projects/dynamic/index.shtml The dynamic range of an audio signal is the difference between the quietest discernible part of the signal and the loudest undistorted part of the signal. It is normally expressed in decibels (dB). - This is a
[filmscanners] Re: Epson 2200 does it exist?
There are a number of people with the 2200 in hand. They exist (even on the west coast of Canada where I am (but are still special order)). You have hit the often created distribution brick wall, which occurs early in the launch of a product that ended up very popular and in demand. Not knowing the exact demand, companies hold back on production in the beginning, as it is better to have people hunger for a product (that has no competition for people to run to) than to flood the channel and end up with a dud that requires price slashing. Further, I suspect Epson is making sure everything is to their liking so that they have minimal returns and don't need to redesign, or if they do, they can do so before many thousands of units get distributed. So, if you must have one, bribe a store into providing you with the next/first one they get in. ;-) Art Stuart Bowling wrote: I traded up from a Nikon LS-30 to a Nikon Coolscan 4000 ED. Now that I have a lot of bits, I would like to see them in the light. There is some talk on the web about the Epson 2200. I see web links to places in UK (I am in the US) that sell the Epson 2100. But the US seems to be dry. I searched the web, and some photostores, computer stores, and circuit stores list the printer, but none seem to have it in stock. Even the online Epson store says out of stock. I can't print my bits on wishware. Can someone tell me what is going on with this printer? Or suggest an equivalent (or better?) A3+ inkjet? I admit to lurking on this list for 2 years. Please don't hold this against me. It is a wonderful list, and I have learned a lot from the members who post to it. Thanks. __ Stuart Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] SS4000 mirror cleaning
Camera repairman said to use lens cleaning tissue only, nothing else. Art wrote: Does he suggest a specific type of tissue (like a Kim-wipe?), or just as soft a one as possible (again with NO pressure) to answer another item: The brush that came with your scanner has very little to do with the optical system cleaning, it gets big stuff off the light source but not the optical mirror or anything important. I think a few posts went by from persons who missed part of the thread about how to tell if your Polaroid SS4000 needs cleaning or how to do it. If you missed out, please post me privately. If a lot of people need information I will post a summary to the group, otherwise I will just answer questions off-list and close the thread. Thanks. -- Thomas Robinson 441 NE Jarrett St. Portland OR 97211-3126 USA 503-460-0415 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 -- resolution/levels
Hi Austin, Sorry, one more post. on 8/30/02 8:28 AM, Austin Franklin at [EMAIL PROTECTED] wrote: Roy, 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. ... I believe the concept of resolution is inherent in the concept of dynamic range. Whether that works for you or not, at least for me, and for many other engineers I know, is an important understanding. Fair enough. But I like to show why I believe that the concept of resolution that results isn't very meaningful. See below. 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. I see how size can have a merit (which is a relative ratio), and range, as they apply to dynamic range. Size in the fact that the largest signal is N times larger than the smallest...and range in that you can say all integer values from 1:1 to N:1. BUT...realize that all integer values from 1:1 to N:1 really denotes a resolution over a particular range too...that you have N discrete values. Yes, but I never said integer. In the real-world i.e. analog, there no reason why any real number couldn't be used. What's wrong with going from 1:1 to 1.01:1 to 1.02:1 ... You don't seem to have trouble when someone says density range and Dmax - Dmin. Why the hangup when the adjective is changed? Because dynamic range and density range are two entirely different things. When someone says a density range of 3.6D, that means from, say, .2D to 3.8D, or whatever. Within that range, you can discern ANY value you want at any resolution you want, down to .001D if you could...but dynamic range, in and of it self, has a number of discernable steps. Density range does not. Here's why I have a problem with the concept of resolution: Let me go through a simple example of a (semi-idealized) scanner. Here's the basic specs of the scanner: Density Range: 0D to 3.6D Bit Depth: 12 bits Number of levels: 4096 A couple of simple observations: The density range is also 12 photographic stops -- each stop is .3 of density so 12*.3 = 3.6 You can chop up the density range into 12 one-stop ranges i.e.: 0 to .3, .3 to .6, .6 to .9 ... etc to 3.3 to 3.6 Photographically and human perception wise each of these one-stop ranges are equivalent in size. So now let's chop the density range into the 4096 levels. The density range 3.6 divided by 4096 gives a little less than 0.001D per level. Approximately, 300 levels for each of the 12 one-stop range. Sounds like a great concept of resolution, doesn't it? We get a new level every 0.001D change in density -- it sure looks like a resolution of 0.001D. Fine, but the trouble is: scanners don't work anywhere even remotely close to that scenario. This is what scanners actually output as the levels: The first one-stop range contains 1/2 of all the levels, the next on contain 1/2 of the remaining ones, etc. until the last one. This is what it looks like: 0 to .3 = 2048 levels .3 to .6 = 1024 levels .6 to .9 = 512 levels .9 to 1.2 = 256 levels ... 3.0 to 3.3 = 2 levels 3.3 to 3.6 = 1 level Pretty weird, but that's the way it is. Here's a web reference that has basically the same table -- just scroll down a ways. http://www.scantips.com/basic14b.html Austin, don't take my word or the web's word for it. Try it yourself. Scan a film step wedge in raw mode on your Leaf 45. I'm hoping you have a 21 or 31 step wedge from Kodak or Stouffer. If you look at the Histogram of the raw 16-bit file you'll see half of the entire range used up with the number of steps in one-stop. It's very surprising when you first see this. So back to the concept of resolution. What is the resolution? At the very dense end the resolution is a whole stop i.e. 0.30D units. At the other end it's close to .3/2048 or 0.00015D units. So, again, I can't feel the concept of resolution is very meaningful -- its just too varied. Roy Regards, 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: Epson 2200 does it exist?
- Original Message - From: Stuart Bowling [EMAIL PROTECTED] Sent: Thursday, August 29, 2002 4:40 PM Subject: [filmscanners] Epson 2200 does it exist? There is some talk on the web about the Epson 2200. I see web links to places in UK (I am in the US) that sell the Epson 2100. But the US seems to be dry. Stuart: My experience is Yes and NO. I live about 45 miles out of Seattle and the nearest honest-to-god camera store near me actually has one that I could drool on. They also had some test prints. I talked to the salesman who is testing this one. He just got it and, so far, has only run a few color charts. The three I saw were each on a different paper and, as he said, none were dialed in yet so I can't really comment on the output. I can take in a file of mine and have him print it. Fortunately one of the papers he is trying to set up on is the paper I normally use. I will get a much better feel for the output then. At present, for color, I am using an 870 and, as long as I frame them behind glass, I have been satisfied. He told me that he was expecting four of them in two weeks. I put my name on the list to be called when they come in. I was number three! They are selling them for list - $695.00 USD. I have been looking on line and see them advertised for up to $40.00 less (plus shipping and handling - $15 to $20?). I think I will go with my local dealer. Having a store 15 minutes from my house that carries Photo paper (digital and traditional), darkroom supplies, cameras, a wide variety of films - including sheet films, books, and knowledgeable people who are fun to talk with is worth a lot more than the on-line savings. Anyway, now that I am through with my rant, yes the 2200 is real but, no, I could not take one home. The salesman sounded more hopeful than sure that he would have his units in the time he was told. The media reviews I have been reading are really high on this printer. I expect the front load of orders for them is high and the bigger dealers are getting them first. Dan Williams 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
Austin, I have never read whatever paper you are talking about, but I GUARANTEE you it does not SAY that dynamic range is a resolution. I am sure that you, Austin, INTERPRET it to say that, but it will not actually say that. You probably should have read the paper before commenting... But no, that is the point. I am confident that I don't need to look at the paper, because I know that no paper will say what you believe. You are mistaken in what you say and still, to this date, after buckets of wasted electrons and keyboard hours, you have still not produced a single reference that says what you say. So I was giving you a FREE KICK - a totally unsupported challenge which gave you absolutely every chance to smother me in extracts from this paper with quotes that agree with you. The fact that you have not done so I think proves the point. Now as for the rest of the post, I am in a bind. If I respond to all of yours, you and others will accuse me of being interminable. If I only respond to what I think are relevant points, you will accuse me of being selective. So I am going to be selective. But I have written a complete response at some cost, and if you want the rest please tell me. ... ***In this case DR = 30 dB ***Resolution is still 36dB if you stick with your formula = max/noise, or 30dB as it obviously is in fact, given you have a digital step size of 1/1024 or 30dB. Well, here you go again, Julian...and this is why I get pissy with you. You take things out of context and apply them to something else. I NEVER said the MDS was ALWAYS noise. In the case of the ORIGINAL SIGNAL, it is noise, in the case of the digitized signal, it is NOT noise. Well let me quote one of many interminable exchanges where I was tearing my hair out because you were insisting that MDS was noise. Please note carefully the contradiction, clear and unambiguous between statement A and the statements B1,2,3 : A) I NEVER said the MDS was ALWAYS noise. - from this post B1) The smallest discernable signal IS noise. - from post in June B2) This is a misunderstanding of the concept of dynamic range. It is ALWAYS based on noise. - post in June B3) Noise and smallest discernable signal are EXACTLY the same thing. - post in June. I have struggled for months to get you to agree that noise and MDS are not the same thing, and now you tell me you have always thought this!! I am pleased that you are coming round, but flabbergasted at the same time. Here is the exchange for the record so you don't accuse me of taking you out of context: --start of exchange last June-- Julian: iii) How can you tell me that smallest discernable signal is not the correct term!? Austin: It IS the correct term, but you are using the wrong definition for it! The smallest discernable signal IS noise. I don't say it IS determined by noise, I say that most of the time it is. Because MOST of the time, the smallest discernable signal is determined by noise, so MOST of the time dynamic range is determined by noise. This is a misunderstanding of the concept of dynamic range. It is ALWAYS based on noise. The importance of this semantic juggling is twofold, first, it is important to understand the DEFINITION of dynamic range, and the fact that it is NOT defined in terms of noise, it IS defined in terms of smallest discernable signal. Noise and smallest discernable signal are EXACTLY the same thing. Second, on those odd occasions when smallest discernable signal is NOT determined by noise, then you need to make sure that noise is NOT in the equation! (which is one reason why your equation has a problem). So, you are saying that my reference material is entirely incorrect? I KNOW that isn't the case. ---end of exchange IN fact, noise and digitised step size are the two things that limit MDS in a scanner, as I have always said. Whichever one predominates determines MDS and thus the bottom half of DyR.. ... : max signal / MDS. This time, MDS is determined by the noise level, because noise level is higher (4 times higher) than the bit size. MDS = noise level = 1/4096. So the DR of this scanner is 36dB again. You could have any number of bits over 12, and it would not change the dynamic range one iota. ***In this case DR = 36dB. ***Resolution is --- 36dB by your formula = max/noise (correct this time), or 42 dB if you just consider digital bit numbers and step size. I really don't know what your point is here. My point was to demonstrate in agonising detail that your unambiguously applied formula for DR (of the system) as something/noise is not always correct, and your unambiguously applied formula that DR is determined by the number of bits is not always correct. We may even agree on this, but in past discussions you have blasted people with these as absolute truths when they are not. The ONLY absolute in dynamic range that is
[filmscanners] Re: Epson 2200 does it exist?
Actually, here in Vancouver Tricera, the main Epson dealer, has at least 8 or so at present, and has sold a lot already over the last couple of months. While I was in there yesterday for some supplies there were 3 customers there who all had bought a 2200 there. At 4:51 PM -0700 8/30/02, Arthur Entlich wrote: There are a number of people with the 2200 in hand. They exist (even on the west coast of Canada where I am (but are still special order)). You have hit the often created distribution brick wall, which occurs early in the launch of a product that ended up very popular and in demand. Not knowing the exact demand, companies hold back on production in the beginning, as it is better to have people hunger for a product (that has no competition for people to run to) than to flood the channel and end up with a dud that requires price slashing. Further, I suspect Epson is making sure everything is to their liking so that they have minimal returns and don't need to redesign, or if they do, they can do so before many thousands of units get distributed. So, if you must have one, bribe a store into providing you with the next/first one they get in. ;-) Art Stuart Bowling wrote: I traded up from a Nikon LS-30 to a Nikon Coolscan 4000 ED. Now that I have a lot of bits, I would like to see them in the light. There is some talk on the web about the Epson 2200. I see web links to places in UK (I am in the US) that sell the Epson 2100. But the US seems to be dry. I searched the web, and some photostores, computer stores, and circuit stores list the printer, but none seem to have it in stock. Even the online Epson store says out of stock. I can't print my bits on wishware. Can someone tell me what is going on with this printer? Or suggest an equivalent (or better?) A3+ inkjet? I admit to lurking on this list for 2 years. Please don't hold this against me. It is a wonderful list, and I have learned a lot from the members who post to it. Thanks. __ Stuart -- *Henning J. Wulff /|\ Wulff Photography Design /###\ mailto:[EMAIL PROTECTED] |[ ]| http://www.archiphoto.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: SS4000 mirror cleaning
Thomas, It would be great if you could post a summary to the list. It would a fine contribution about scanners and would help to dilute the 'dynamic range' dirge. That's one dead horse that takes a licking and keeps on ticking. -JimD At 06:18 PM 8/30/2002 -0700, HPA wrote: Camera repairman said to use lens cleaning tissue only, nothing else. Art wrote: Does he suggest a specific type of tissue (like a Kim-wipe?), or just as soft a one as possible (again with NO pressure) to answer another item: The brush that came with your scanner has very little to do with the optical system cleaning, it gets big stuff off the light source but not the optical mirror or anything important. I think a few posts went by from persons who missed part of the thread about how to tell if your Polaroid SS4000 needs cleaning or how to do it. If you missed out, please post me privately. If a lot of people need information I will post a summary to the group, otherwise I will just answer questions off-list and close the thread. Thanks. -- Thomas Robinson 441 NE Jarrett St. Portland OR 97211-3126 USA 503-460-0415 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
