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Author Topic: DCF Full Spectrum plug-in  (Read 64460 times)
digitaldog
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« Reply #20 on: April 16, 2006, 05:56:34 PM »
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Just as I can purchase a Photoshop plug-in that gives me a cross-processed look, I can just as easily get the same result with a number of Photoshop tools, like Channel Mixer and/or curves.

One is infinitely easier to do than the other even for novice users. And while I agree that there are plenty of ways to produce effects in Photoshop (using its tools or others), its all about price to performance ratios. Again, I'm seeing what appears to be a solution in search of a problem.
« Last Edit: April 16, 2006, 06:12:15 PM by digitaldog » Logged

Andrew Rodney
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« Reply #21 on: April 16, 2006, 06:12:05 PM »
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Your program is not what you are claiming. You state there is an issue with how cameras record purple, but there is not as demonstrated by the photos of the Color Charts. The difference between what people mistakenly see as purple and what the camera records is an optical illusion (two separate colors - blue & magenta - blending together).

Your program fixes that "issue" by implementing a hue change. Something you admit can be done in PS. Granted there is nothing wrong with offering another means of doing so, you are claiming there is this issue when the camera is actually recording purple. In addition you are making vague (and disingenuous) claims of using a larger color spectrum.

So my question is this, which is it really? Is it a matter of just adjusting hue, or are you doing some fancy conversions using color profiles of some sort? If the latter, lets here some technical explanations. What are the RGB cords, gamma and temp of the color space you work with, what is the frequency range in numbers of the "full spectrum" you are interpolating into the image, and how are you implementing this supposed spectrum?

You claim cameras don't use a full spectrum in the fact they don't record the shorter wavelengths of light. How could you use a full spectrum in your corrections when the camera didn't record the information to begin with? For us to believe your primary claim, we must first have to accept that your software is able to create something from nothing. Not only that, but that something is a color of light that you couldn't even possibly know existed to begin with.

All of the other adjustments made by the program are simple hue, saturation and contrast adjustments.

The summary here is that you are claiming to use this mysterious spectrum of color in some vague way to correct a problem that does not truly exist. Lets hear some substantiated information to back up your claims rather than vague references and unidentified "experts."
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digitaldog
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« Reply #22 on: April 16, 2006, 06:14:46 PM »
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The summary here is that you are claiming to use this mysterious spectrum of color in some vague way to correct a problem that does not truly exist.[a href=\"index.php?act=findpost&pid=62747\"][{POST_SNAPBACK}][/a]

I've asked the always unflappable Dr. Karl Lang () to comment on all this "color science". I hope he pings us about this so called "issue" with digital cameras and "RGB". That will make this post quite entertaining (and educational).
« Last Edit: February 05, 2007, 03:26:00 PM by digitaldog » Logged

Andrew Rodney
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tribecalabs
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« Reply #23 on: April 16, 2006, 07:48:47 PM »
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Happy Easter.

Michael Bevans
www.tribecalabs.com
« Last Edit: April 16, 2006, 07:53:03 PM by tribecalabs » Logged
dwm1953
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« Reply #24 on: April 16, 2006, 09:21:14 PM »
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Mike, I applaud your patience in explaining your product to a skeptical audience. I have seen other company reps lose their cool under similar circumstances. I just spent some time at your website looking over your software. I see that the plug-in works within RGB and re-maps values in the uncorrected image to new values for the "correct" image produced by Full Spectrum. Nothing magical. Something an experienced photoshopper could do given the time and inclination. Just as many other plug-ins, it automates a process that can be done manually.

I think there is something to your argument that purples are not well reproduced (I have experienced this myself), however whether this is due to an inherent limitation in the RGB model or not, is not clearly demonstrated at your site. You provide anecdotal justification for the hypothesis but no real scientific explanation. This leads to skepticism and an unwillingness to part with $50 without first giving the plug-in a spin. As someone else pointed out (and you alluded to) a demo version is definitely needed here.
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paulbk
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« Reply #25 on: April 16, 2006, 10:04:19 PM »
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re: DCF

Michael Bevans,
The more I play with DCF the more I like it. You need better documentation. You need to tell more sophisticated users "what exactly" each control is doing. For example, is the blue slider making the "b" curve in Lab steeper? Give me some indication what I'm really doing with out giving away the store.

Anyway, good luck with DCF. There may be a user base out there but you gotta upgrade the documentation.
paul
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paul b. kramarchyk
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digitaldog
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« Reply #26 on: April 17, 2006, 07:50:18 AM »
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I think there is something to your argument that purples are not well reproduced (I have experienced this myself), however whether this is due to an inherent limitation in the RGB model or not, is not clearly demonstrated at your site.

I've seen a fair number of output profiles shift blues to magenta or cyan but this is more an issue of a profile not really doing a very good job of handling either gamut mapping or handling blues. Going back say 5-6 years ago, there were few profile packages that handled this blue issue well. Today it's the exception to the rule.
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Andrew Rodney
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« Reply #27 on: April 18, 2006, 01:54:46 PM »
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Once again, great questions and comments. I will try to address each in turn. I am sure that my answers will raise more questions and comments.

Thank you, dwm1953. It is true that new technology is often greeted with skepticism at first. I recall in 2000, when I was a technical-rep for a digital camera-back manufacturer, introducing digital cameras to reluctant professional commercial photographers. Now digital cameras outsell film cameras. Opinions change quickly. I appreciate this forum as an opportunity to share information.

“You provide anecdotal justification for the hypothesis but no real scientific explanation.” The scientific explanation is simple; we observed a well documented problem, devised a theory to solve the problem and tested (and tested and tested). In short, DCF Full Spectrum is our proprietary color specification model designed to overcome color deficiencies identified by means of a full-blown psychophysical analysis of color difference between two color systems, RGB and human color perception. It is a color appearance model, or what I have earlier referred to as a palette of colors. To address the concerns of 61 Dynamic, DCF Full Spectrum is entirely device independent and will work with any color space. It does not alter balance, exposure or color settings.

I first noticed a deficiency in digital capture in 1998 at the Herbert F. Johnson Museum of Art at Cornell University working on one of the first large-scale digitization and preservation projects in the country. Over the course of two years, along with two other photographers, cataloguers, technicians, administrators, and museum staff, we set about the ambitious task of digitizing the entire collection of the museum, over 25,000 works of art. Scanning and quality checking over 65 high resolution images a day in a fully color managed environment, I began to notice that digital capture had a difficult time reproducing certain hues, regardless of the attention spent on proper balance and exposure, and regardless of the calibrated monitors and daylight balanced full spectrum lighting. It was curious, because I could create all the colors on the computer (I remember plotting colored points using Basic in junior high school), but the camera/monitor system could not properly characterize wram greens, deep blues, indigos and of course, purple.

Robin Myers, inventor of ColorSync confirms this observation in a very good article about the digital reproduction of art in which he notices a problem with reproducing cobalt blue, http://www.betterlight.com/pdf/whitePaper/...urate_photo.pdf. In this article, he addresses 61 Dynamic’s question regarding what the camera actually records. Mr. Myers states that “The basic camera sensor is panchromatic.” A sensor quantifies all wavelengths of light, using filters to limit the sensitivity of a sensor to certain portions of the spectrum. The sensor itself does not see colors; it quantifies volumes of light data. The RGB colors that you see on your screen are mapped using CIE colorimetry.

Charles Poytnon, Fellow of the Society of Motion Picture and Television Engineers and author of the ubiquitous ColorFAQ and GammaFaq explains, “Color in the real world is best described in terms of distribution of power across the spectrum of visible light. Human vision maps these power distributions into sensory values, then processes these signals at successively higher and higher levels. The famous CIE color matching functions define the mapping from spectral power distributions (SPDs) to tristimulus values; these values are then the basis of color systems used for measurement and image coding. However, psychophysical data has now revealed the "cone fundamentals" that are taken to be the raw spectral sensitivities of human vision. The cone fundamentals don't quite match the CIE color matching functions,” or more simply, “Existing, practical cameras and scanners have spectral responses that don't closely resemble either the cone fundamentals or transformations of the CIE color matching functions. Therefore, these cameras see some colors differently from the way that vision sees those colors.” - http://www.poynton.com/notes/bio/goals.html

DCF Full Spectrum does not create something out of nothing; it remaps data quantified by the sensor. As dmw 1953 states, this is nothing magical; it just hadn’t been done before. Maybe my explanation has provided insight as to why. Certainly if you want to manually color match individual colors using an image editor, there are a million ways to do this. DCF Full Spectrum is a comprehensive automatic solution to an industry wide problem so you don’t have to.
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digitaldog
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« Reply #28 on: April 18, 2006, 02:32:49 PM »
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DCF Full Spectrum does not create something out of nothing; it remaps data quantified by the sensor.

The sensor is simply a photon counter and is color blind (RAW data is essentially Grayscale data).

How is the data quantified given this fact?
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Andrew Rodney
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« Reply #29 on: April 18, 2006, 05:53:14 PM »
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The sensor is simply a photon counter and is color blind (RAW data is essentially Grayscale data).

How is the data quantified given this fact?
[a href=\"index.php?act=findpost&pid=62981\"][{POST_SNAPBACK}][/a]
Given that information and the fact that each camera has its own interpretation of color due to variations in the color filters used on the sensor and the variables in the numerous means to convert the raw data to a working image file (each with it's own interpretation of the original luminosity data), how can DCF-FS possibly begin to know how to properly correct the color the camera recorded?

How can it know what needs to be "quantified" and how it needs to be "quantified" when it hasn't a clue what the original color could have been?

Does your software have specific color adjustment profiles for each camera made using each of the possible means of raw conversion in order to know how the adjustments should be made? Or does it just assume that all blue hues it receives should have more magenta in them regardless of what it is processing?
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tribecalabs
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« Reply #30 on: April 19, 2006, 05:54:01 PM »
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It is true, a digital camera is only a photon counter. Digital cameras do not see colors. As the Robin Myers article details, “The basic digital camera sensor is a panchromatic sensor; it responds to light from the ultraviolet through the visible, and well into the infrared spectrum. To produce a color sensor, filters are applied to its surface to give the sensor color selectivity. Each filter limits the panchromatic response of the silicon sensor to a small portion of the spectrum.” http://www.betterlight.com/pdf/whitePaper/...urate_photo.pdf

Charles Poynton’s Guide Tour of Color Space provides more information on transforming input voltages into color signals in his article “A Guided Tour of Color Space.”
http://www-scf.usc.edu/~csci576b/Slides/Le...or%20space'

And, finally, for an excellent interactive on how to build a CCD you can check out this page: http://micro.magnet.fsu.edu/primer/digital...ccdanatomy.html

In any event, suffice it to say that input voltages are converted to color values using a color specification system based on CIE colorimetry (otherwise we’d only have black and white digital cameras).

As already described by Poynton in an earlier post; however, this system is necessary for encoding digital images but not sufficient to produce colors that accurately simulate human color perception.

To answer Dan’s question, DCF Full Spectrum is a proprietary device independent color model. It does not rely on data about the camera system in order to transform colors. For more information on how DCF Full Spectrum characterizes colors, refer to http://www.tribecalabs.com/technology.htm.

-Mike Bevans
www.tribecalabs.com
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digitaldog
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« Reply #31 on: April 19, 2006, 06:17:43 PM »
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You're doing a fine job of providing links to useful articles that in no way backs up ANYTHING you've said about your product. This is getting silly too. You've got RGB data and all you can do is change the numbers one way (and affect other numbers too). This isn't anything at all different from my Selective Color tweak in Photoshop where I took some existing RGB numbers and altered them in one direction or the other. All this talk about proprietary this and that doesn't really change the fact that you're not doing anything at all unique. Now if you want to tell folks "we have a easy button that shifts blues one way or the other in the event you find alternative controls in Photoshop diffuclt" I'm OK with that. But there's a great deal of smoke and mirrors and a huge BS factor on your web site with very little to back up anything other than "we have a make pretty button for blues."

If your idea of selling this "technology" is to have someone photograph your web page and view the results on their cameras LCD, I think you're talking to the wrong crowed here.

So this is some proprietary device independent color model is it? So you're doing color space conversions? Or, as I suspect you're simply altering selective color numbers in one direction which really isn't all that unique (Photoshop has been doing this since 1989 before it was called Photoshop.
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Andrew Rodney
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« Reply #32 on: April 19, 2006, 08:39:06 PM »
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To answer Dan’s question, DCF Full Spectrum is a proprietary device independent color model. It does not rely on data about the camera system in order to transform colors. For more information on how DCF Full Spectrum characterizes colors, refer to http://www.tribecalabs.com/technology.htm.
[a href=\"index.php?act=findpost&pid=63111\"][{POST_SNAPBACK}][/a]
As I suspected. DCF-FS is simply a simplified Hue/Saturation/Contrast tool. Perhaps it's using proprietary variation of CIE Lab to do so, but it certainly is not a tool that is capable of correcting this "problem" you keep describing.

As Rodney pointed out, you are throwing out a fat load of BS to make it sound like your program is allot more than it really is.
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digitaldog
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« Reply #33 on: April 20, 2006, 08:16:33 AM »
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As Rodney pointed out, you are throwing out a fat load of BS to make it sound like your program is allot more than it really is.
[a href=\"index.php?act=findpost&pid=63124\"][{POST_SNAPBACK}][/a]

I feel a bit guilty that I'm busting Mike's balls (well I am a bit). Again, if the intent is to make it easy for novice users to "fix" an issue with blues (which I submit has nothing to do with digital sensors per say and have shown with a $200 point and shoot), fine. But the message is getting lost in the high signal to noise ratio which at this point does appear to follow your above description (a fat load...).

For the life or me, I can't find anything my quick and dirty tweak in Photoshop didn’t accomplish with respect to fixing the blues. But I fully admit that some users may not know how to do this (although it's pretty darn simple and a one page tutorial would set anyone willing in the right direction).
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« Reply #34 on: April 20, 2006, 10:29:20 AM »
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Adjusting Hue in Photoshop with the Hue and Saturation adjustment layer is easy. Just set it to blues only, slide the hue a bit to add some purple into the blues and you're done. Adjust to taste - yummy. Quick, easy and painless. You could even make it an action if you've got preferred settings.

I'd totally agree that this is  not a camera issue. The gamut of colours that a camera sees is just fine, but yes, there is no one perfect colour matrix to convert that image the camera sees to full RGB colour. That's where your photography eye comes in, to adjust your image in post to your liking.

What I want to know about DCF, is if you take a picture of something blue, and it looks blue in Photoshop, then applying the DCF will turn it, or part of it, purple, and that would be less accurate. How does it tell blue from blue that stays blue, and blue that's really purple. And given that each camera sensor's colorimetry is different, and each gets turned to RGB via a different colour matrix, how can it ever be accurate? If it is, as I surmise, purely perceptual and subjective, then tweaking the hue to taste, as I outline above would be the easy and free solution.

Graeme
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paulbk
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« Reply #35 on: April 20, 2006, 04:21:37 PM »
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DCF example test files below:
Camera: Canon 1D Mark II, RAW mode
RAW Conversion: default Adobe Camera RAW auto-mode, 16 bit, Adobe(1998)

Converted RAW file was duplicated.
Left file -- no further processing after RAW conversion.
Right file -- only "default" DCF Full Spectrum processing applied after RAW conversion.
DCF adjustments are available in "Control Panel" mode. I didn't use them. If I'm going to tweak, I'll do it myself using a Lab curve without use of DCF.
Each file resized to jpg, sRGB, and posted.
« Last Edit: April 20, 2006, 04:35:53 PM by paulbk » Logged

paul b. kramarchyk
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digitaldog
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« Reply #36 on: April 20, 2006, 04:40:37 PM »
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The sky on the left looks better to me. But either would fly and the differences are not much. It looks like the nice blue sky in the left went magenta in the right...
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Andrew Rodney
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« Reply #37 on: April 20, 2006, 06:02:19 PM »
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I think the image that has not had DCF applied looks better. The sky is purple in the DCF one (see my comment about it cannot know which blues are really blue and which are really purple) and the green grass has turned brown.

Graeme
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« Reply #38 on: April 20, 2006, 07:27:35 PM »
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I feel a bit guilty that I'm busting Mike's balls (well I am a bit). Again, if the intent is to make it easy for novice users to "fix" an issue with blues (which I submit has nothing to do with digital sensors per say and have shown with a $200 point and shoot), fine. But the message is getting lost in the high signal to noise ratio which at this point does appear to follow your above description (a fat load...).
[a href=\"index.php?act=findpost&pid=63164\"][{POST_SNAPBACK}][/a]
I don't feel guilty. If Mike was making these claims out of honest ignorance, then that would be forgivable. I have a hunch that is not the case since the entire company seems built upon this one fallacy. He makes certain claims and it is up to him to prove them yet the guy continually throws out the same uninformative or off-subject garbage in his replies.

If a company is not going to be upfront and honest, then by all means they deserve every ounce of criticism they get. I have little tolerance for any business, big or small, that tries to take advantage of people who don't know any better.

Maybe he'll prove me wrong with his next reply(s) if he decides to continue in this thread.
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digitaldog
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« Reply #39 on: April 20, 2006, 07:29:31 PM »
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... the green grass has turned brown.
[a href=\"index.php?act=findpost&pid=63202\"][{POST_SNAPBACK}][/a]


Good call! I was too quick to view the two images and missed the grass. That's absolutely a deal breaker in the 2nd image. So I think you're spot on; you alter the image that doesn't need alteration, you can hose the file. BTW, a phone conversation I had with Karl Lang yesterday about this topic confirmed what you're saying: you have to move the values in one direction or another and assuming the image is OK to begin with, such a tool can produce as many problems as it hopes to solve.
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Andrew Rodney
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