Has anyone tried this? DCF Full Spectrum

This from Jon Cone's Inkjet Mall... "This unique technology allows your camera to reproduce all colors accurately, including difficult hues such as violet, deep blue, and sunlit green.

The RGB (Red, Green, Blue) color model was designed for the efficient production of colors using a trichromatic light emitter, such as a computer monitor or a camera LCD. It is a model for producing illumination; it was not designed to simulate the complexity of human color vision. Although RGB can be used to produce millions of color combinations, the hues are not arranged in a way that is consistent with how we see. As a result, digital cameras generate a simplified, limited spectrum."

I have it. It was inexpensive so I thought it would be a good addition to the CS2 "arsenal", but I haven't used it enough to really comment whether it is worth the effort or not.

This looks interesting but I don't want to spend even 50 bucks on a product where I can't test it first on my own images. There needs to be a trial version of this product. I couldn't find any sort of reviews on it either.

T

What has Jon been smoking <g>

This was discussed in length on the ColorSync list (see URL below). The color geeks dismissed it as flat out BS! Don't waste your money or your time.

http://lists.apple.com/archives/colorsync-...r/msg00245.html
Especially useful:

http://lists.apple.com/archives/colorsync-...r/msg00249.html

Every Macbeth Color Checker I've ever seen has a nice purple patch (Patch 10 and not too far off, patch 17). So I took my wife's Digital ELF PHD camera and shot one. This isn't what I'd call a high end camera guys. Do you see anything wrong with those patches?

re: DCF...... Save your money!

I start with a simple extracted JPG from 1D mk2 RAW file, same file processed in both cases, and ONLY the corrections noted:
LEFT chart... DCF Full Spectrum Correction applied.
RIGHT chart... only levels with snap neutral midtones applied.

Looks like DCF turns blue to purple. Pathetic.

When you go from RAW from the sensor, to RGB in Photoshop, there are a few things that happen along the way. One is the colour matrix, which is a 3x3 set of values that transforms the colour space of the camera with respect to the incoming light and the RGB filters on the pixels into the RGB space of whatever you choose your RGB space to be. Looks to me that DCF are tweaking those values to use a different RGB transform matrix. Look slike nothing you can't do with Photoshop and a bit of time on your hands to get the exact values, then make it an action....

Graeme

It's obvious just by looking at their sample images that the program is doing nothing more than shift the hue of blue. But hey, it has contrast and hue adjustment sliders too so it must be worth $50.

Mr. Rodney, thank you for providing such a good image of the Macbeth Color Checker so that I can demonstrate the effects of DCF Full Spectrum.

DCF Full Spectrum is a nonlinear RGB color palette for designed to simulate the complexity of human color perception.

The RGB model used by all digital cameras is a model designed for the efficient production of illumination using three colored stimuli. Colors are spatially and perceptually even fractions of the whole. They remain chromatically constant as their value is changed. Human response to a color, on the other hand, is not usually described as spatially and perceptually even fractions of the response to illumination. We have a much more complex processor than that. We know intuitively that as a color becomes darker it becomes deeper. This is a human characterization. A digital camera does not characterize, it can only quantify. The result is that darker colors, like purplish blues lack the characterization of purplish and simply get displayed as dark blue. (If you have ever watched the LA Lakers or the Minnesota Vikings on TV, you will know what I mean by the above. On TV, their jerseys appear dark blue, but in real life their jerseys are deep purple.)

DCF Full Spectrum characterizes the data quantified by a digital camera to produce more photorealistic images.

The image on the left is the image Andrew Rodney provided, the image on the right uses DCF Full Spectrum. As pointed out, the most obvious difference is that the DCF image has deeper blues (or to use their descriptive ISCC/NBS names “purplish blues”). Additionally you may also notice warmer, deeper greens and oranges. In fact, closer examination reveals that all colors go through a transformation. Improved color contrast, the perceived brightness of adjacent colors, means DCF images looker sharper and more clear with no sharpening.

While we are in development of a water mark version of DCF Full Spectrum, we will happily process test images for those who wish to evaluate results before making a purchase, for information e-mail contact@tribecalabs.com.

Thank you,

Mike Bevans
Tribeca Labs
www.tribecalabs.com

I'm looking at both files after downloading and assigning sRGB (not the silly camera RGB profile the toy Canon tagged, should have done that first) and in Photoshop, I'm not seeing anything the image to the right really brings to the party. Certainly when comparing it to a LAB Macbeth version and certainly not withstanding a tweak (if anyone even thinks it's necessary) with selective color.

The web site makes it pretty clear this some heinous issue with digital cameras and this $50 product is a godsend but I still think, based on this test that you've got a solution in search of a problem.

Least we forget, this is a Macbeth JPEG from a $200 Digital Elf circa 2003 or so.

Curious reading about that hue error compensation that the plugin does. Sounds like it's trying to repair the gamma error damage from 2.2 boost. If you work on linear intensity space this plugin probably is not worthwhile. (I probably should test it myself before commenting ...)

Mike Bevans, Tribeca Labs

See my examples below. Why does DCF Full Spectrum correction turn blue (col 1, row 3) to purple-ish?

I've tried this many times using different RAW convert software and making no corrections in PSCS2 other than DCF. My color checker was shot in bright sun using Canon 1D Mark II. I generally like what it does to all other colors except the shift in blue to purple. Can't use it with a clear blue sky, it makes it purple-ish.

RAW.. white balance, convert to color space = Adobe1998
LEFT target: Photoshop.. no correction
RIGHT target: Photoshop.. DCF Full Spectrum applied
Both files converted to sRGB for web JPG examples.
sRGB looks no different then Adobe1998 on my calibrated monitor.

p

Paul,

DCF Full Spectrum is a color palette designed for digital photography. Just like back in the day when you would choose between Kodak and Fuji film, you were choosing different palettes. Both Kodak and Fuji film could be properly exposed and balanced; however, it was commonly believed that Kodak had deeper blues and Fuji had more vibrant reds. The color palettes between the two films were different.

DCF Full Spectrum is an alternate RGB palette for digital photography. DCF Full Spectrum is our “Reala” film, DCF Portrait is our “Portra” and DCF Vivid is like “Velvia”. Using the DCF Control Panel, you can customize your own color palette.

Before I begin an analysis of your results, a couple things should be pointed out. You mention that you shot the color target in bright sunlight. If this is the case, your starting exposure is a little bit down. According to the folks at gretag, the white square on the color chart will read about 243RGB when properly exposed, whereas the white patch on your color target reads about 220RGB. Also, it should be noted that even though your white balance is correct the appearance of the blue squares in question will vary when removed from sunlight and viewed inside next to a monitor. White may still look white (because the brightest white in the scene is your eye’s white point) but the particular blue square you mention will appear much redder when in sunlight (depending on the tiome of day) than it does indoors. I mention this simply to point out that we don’t have an apples-to-apples test to begin with.

That said, you are correct, DCF Full Spectrum blues are more purplish. The blue you refer to is actually called "vivid purplish blue" (and the blue patch up and to the right from this one is referred to as "strong purplish blue") by the Inter-Society Color Council (ISCC) and the United States Department of Commerce's National Bureau of Standards (NBS) (now called the National Institute of Standards and Technology).

DCF Full Spectrum is a color difference model between RGB and human color perception. It is our definition of digital color fidelity. How much your particular camera differs from our default setting may vary, based upon camera performance(exposure, for example) and individual preference. If you feel the color is too purple, you can use the DCF Control Panel to define your own settings.

By turning OFF DCF Full Spectrum in the Control Panel and turning ON the Additional Controls, you can set your own difference model using our color formula (to varying degrees). Set each of the four color sliders to 50% resulting in a formula equal to our default DCF Full Spectrum. I recommend setting all of the sliders at their 50% position (equal to our default) but turning down the Blue slider to 33-25%. You will still see deeper blues and purples, but not quite as strong as our default.

Once you have a setting you like, you can create a Photoshop Action that LOADs your preferred setting. (To record this action, open a dummy image, click the LOAD button in the DCF Control Panel and load your preferred setting). Once you have done this, you can simply run the action without needing to go through the Control Panel step.

Thank you,

Mike Bevans
www.tribecalabs.com

There's a difference between a product that adds a number of styles - or film emulations - and then claiming that digital cameras do not record purple, is there not?

Despite the claim on the front page of your website: "Your eyes see purple. So why doesn't your camera" both my digital cameras are perfectly capable of recording purple.

There's nothing wrong with your product, only with your fraudulent advertising.

I think you hit the hammer on the nail here! Good job.

I'm shooting RAW, and I have all kinds of tools at my disposal for producing a myriad of renderings (flim looks plus!). Check out the HLS controls in Lightroom. Talk about a great tool for tweaking all kinds of renderings (and yes, you can do this on rendered files as well).

Oh, I'm so looking forward to Lightroom being available on Windows! Right now I have to tweak all my important pictures individually in Photoshop since I'm not happy with the controls of any current raw converter. The resulting file sizes (and time spent) are less than ideal, and from what I've heard Lightroom sounds like a big step in the right direction.

Thank you for the constructive criticism regarding our website. We will certainly take your comments into consideration as we redesign our website and fine-tune our message.

As we are all aware, color is a complex subject, and reducing the discussion to a simple statement appears to have caused some controversy. In no way do we intend to deceive, we simply want to make a case for a real solution to a real problem.

The problem addressed by DCF Full Spectrum is that the RGB system reproduces an incomplete spectrum of colors. As you can see in the digital recording and reproduction of the component colors of sunlight (the spectrum shot below), RGB systems have difficulty reproducing shorter wavelengths of light (original image on the left). In the Full Spectrum RGB image on the right, you can clearly see how the spectrum includes the shorter wavelengths of light for a more complete reproduction of violet, and in turn the whole spectrum.

Click to view attachment

This is what we mean when we say: “Your eyes see purple, so why can’t your camera?”

The poor sensitivity to violet can also be seen in this image of the LA Lakers jersey. If you have ever seen the Lakers on television, you will see that there jerseys appear bright blue, like the original digital capture on the left. The Lakers jerseys are purple, like the Full Spectrum RGB image on the right.

Click to view attachment

We first noticed the shortcomings of RGB in digital fine-art reproduction where color matching is critical. Tribeca Labs’ color experts have worked extensively with museums and cultural institutions involved in large scale digital preservation projects since 1998. Working in fully color managed environments with the highest resolution digital scan back cameras, we have been able to confirm that the problem is common and can be seen in every camera or monitor.

For nature photographers, DCF Full Spectrum provides richer, more photorealistic and natural colors, as you can see in the following images of flowers (original on the left, Full Spectrum RGB on the right).

Click to view attachment

Click to view attachment

Mark.S asks, “There's a difference between a product that adds a number of styles - or film emulations - and then claiming that digital cameras do not record purple, is there not?”

The comparison between Kodak film (deep blues) and Fuji film (vibrant red) was made to illustrate the concept of a color palette. For example, to say Kodak film has deeper blues than Fuji film is like saying Full Spectrum RGB has deeper blues than RGB alone.

Admittedly, one problem we have with our advertising is that people think that DCF Full Spectrum only affects purples. In the shot of the trees below you can see how DCF Full Spectrum brings out the complexity of greens, producing a better sense of space and dimension (RGB on the left, Full Spectrum RGB on the right).

Click to view attachment

Full Spectrum RGB is available in two additional settings, the “number of styles,” to which Mark.S refers: DCF Vivid and DCF Portrait. These are optional intensity settings that make use of the expanded Full Spectrum RGB color palette. The following photographs make use of DCF Vivid color (original image on the left, DCF Vivid on the right).

Click to view attachment

Click to view attachment

Click to view attachment

The above images are compliments of the photographers at www.sxc.hu.

Finally, because we know photographers like to make their own adjustments, we added the DCF Control Panel that allows the user to compose his own color palette and intensity settings.

I hope this clears up any misunderstandings. If you have any questions, you can contact me directly at mike@tribecalabs.com.

Sincerely,

Michael Bevans
www.tribecalabs.com

Still don't get it. Notice my simple Photoshop fix using selective color. Two sample points in Info palette with before and after numbers show my simple tweak produced the same fix. This "fix" assumes I actually prefer the color on the right side compared to the left in the original file. Bottom line however, it's super fast and simple to produce this rendering in Photoshop.

Digitaldog, you should turn that into an action and sell it! :-)

Graeme

Mr. Rodney,

Thank you for pointing out that there are many ways to skin a cat.

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. Similarly, I can purchase a plug-in that gives me a better neutral balance, an infra-red look, or a "nocturnal look", or I can spend my time in Photoshop using the tools available to get the look I want.

Obviously there are any number of tools that allow retouchers to manually adjust the colors of individual images.

The point of any program is to make a process easier. If you prefer to spend your time editing each individual picture, you can,or you can purchase a program that saves you time and effort and may well produce a superior result to manual intervention.

Happy Easter,

Michael Bevans
www.tribecalabs.com

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.

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."

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).

Happy Easter.

Michael Bevans
www.tribecalabs.com

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.

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

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.

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.

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?

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?

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

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.

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.

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).

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

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.

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...

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

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.

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.

Frankly, all this is "much ado about nothing". Either use the pluggin. . . or not. It does work. I shoot fashion where color is always a problem with garments. Most files are handed to clients in AdobeRGB (their request). In my view, I've done my job when I can get the garments as close as possible. It's the pre-press house that needs to do final color matching.

Andrew's example of how he matched the purple-ish Laker's jersey has a flaw. Sure, he matched the purple, but the gold was still off and greenish on my monitor (yes, calibrated).

The point is, you can chose to buy the plugin or not. I've bought lots of pluggins and actions over the years that have proved either ineffective or a waste of money. Case in point: Andrew's own PixelGenius enterprise produces PhotoKit Sharpener. I bought it. Used it some and decided I prefer using Nik Sharpener 2.0. It's not that PK Sharpener is no good, only my preference.

It's sad to see people be so bombastic in their approval or disapproval of products. There are lots out there that ARE total garbage. In this case, we're talking subtleties, not a "blow you away" pluggin. To me, a lot of this smacks of a "turf war" and who's the expert or not.

Looks just fine to me (yup, calibrated display). Are the two sets of RGB numbers identical? Probably not. But that's a moot point. I could easily have messed with the yellows too. The color appearance after my edit doesn't seem to be an issue.

What IS an issue is the BS factor of the site selling this product. I think we've all been pretty clear that a plug-in that provides a "make blues pretty" button is fine as long as you tell folks that's what it does. But to put up a bunch of bogus technical nonsense about how cameras can't "see" blue or suggesting you photography your display when viewing their site and examining the LCD on a PHD camera as evidence that there's some kind of color issue with digital cameras is insulting and well, plain BS.

No one is disputing the plug-in might have merit for some users who don't know Selective Color in Photoshop from the crop tool. If it fixes your blues and you find the $50 a worthwhile investment, far from anyone to fault that. But lets cut the Krap and stop providing URLs that don't back up the fact that the premise provided on the web page about this product is Krap.

Nope; sorry I have to disagree.


Michael,

In the meantime state-of-the-art digital cameras were reported to have a metamerism index of above 90% or so (according to ISO 17321). Since perfect color reproduction is scaled to a value of 100, any sensor that achieves a metamerism index above 90 should be capable of providing great color.

Actually the spectral response of Bayer R/G/B filters can come close enough to a linear combination of the CIE XYZ matching functions (depending on the camera of course). So that a simple 3 by 3 matrix can be used in software to recover the corresponding XYZ values, or for direct conversion to a common output space like sRGB, aRGB, pRGB ... In other words, within a quite large 'triangular' matrix gamut digital cameras see nearly the same as the human obverver. Note, I don’t say perfectly.

Talking about: a preferred color reproduction, a pleasing rendition (output-referred), Color Appearance Models, etc. ... that’s a different story.

So where exactly lies the problem which your plug-in intends to cure?

Please be clear.

Peter

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I did a test today to see if there's really a problem with DSLR not seeing purple colours.
Used 30D to take a shot of my MTB club jersey - it has a very nice gradient from light blue through deeper blue to purple. Effectively, on the camera's LCD the colours really looked very much off - the purple became blue and blues were shifted to cyan. BUT, when the RAW file was opened in ACR 3.3 (calibrated for the shooting conditions using GMB chart as explained by Bruce and others) everything became very much normal - all hues snapped to their correct values and the screen to object match was nearly perfect (needed a bit of saturation increase to get exact match).
FWIW.
Allan

From the FAQ's on Munsell Color Science Laboratory:

Question:
"Digital image sensors (such as those used in digital cameras)use red, green, blue ink-based color filters to generate color. Do they therefore have a color gamut that limits the range of colors that they can detect? (255)"

Answer:
"Let's start with the short answer to your question; there is no such thing as a camera, or scanner, gamut. A gamut is defined as the range of colors that a given imaging device can display. To say that a camera had a gamut would be to imply that you could put a color in front of it that it could not possibly respond to. While it is certainly possible that two colors that are visually distinct might be mapped into the same color signals by a camera, that does not mean that the camera could not detect those colors. It just couldn't discriminate them. For example, a monochrome sensor will map all colors into a grayscale image and encode it as such. Certainly the encoding has a gamut (in this case a lightness range with no chroma information), but did the camera responded to all the colors put before it. It is the encoding that imposed the gamut. In the color world, encoding is based on some explicit or implied display. For example, sRGB is a description of a display and therefore defines a gamut (but only if the sRGB values are limited in range). If a camera encodes an image in sRGB, that doesn't mean that the range of colors the camera detected are only from within the sRGB display gamut, but it means the camera data have been transformed to best use that sRGB encoding. As long as a camera has three or more sensors that span the visual spectrum, then it will respond all the same stimuli as our visual system. Whether the camera can discriminate colors as well as the human visual system will depend on the encoding of the camera signals, quantitization, and the details of the camera responsivities. (To return to the black and white system, that camera encodes all the colors into a gray scale. They could then be displayed as any color within a given display, but many colors from the original scene would be mapped to the same values.)

Since there is no such thing as a gamut for an input device, then there is no way to compute it or calculate a figure of merit. Generally, the accuracy of color capture devices is assessed through the accuracy of the output values for known inputs in terms of color differences. Also, sensors are sometimes evaluate in terms of their ability to mimic human visual responses (and therefore be accurate) using quantities with names like colorimetric quality factor, that measure how close the camera responsivities are to linear transformations of the human color matching functions. Doing an internet search on "colorimetric quality factor" will lead you in the right direction."

Herman

Guys, the horse is nearly a wet puddle on the ground, it can't pull the plow anymore.

No kidding, there's nothing left to beat.

Hermie,

Please let me briefly comment on this Munsell quote, because I still believe that the whole story is much simpler than it seems:

The naked RGB triplets as released from Bayer interpolation *can* be assigned to a quite large matrix space as the input profile. To my best knowledge, that’s the way Camera Raw works. And this approach will work so much the better, the closer the spectral response of Bayer R/G/B filters comes to a linear transform of the CIE XYZ matching functions.

BUT – unlike output devices which have a rigid output gamut – this input gamut more describes a sphere of accuracy. Within this sphere the camera 'sees' about the same as the human observer. But, even outside from this sphere, a camera will probably respond to 'everything’ like e.g. spectrally pure laser beams. Just, this doesn’t lead to accurate data.

So if the Munsell lab likes to capture laser beams, then they’re right. There’s probably no camera and input gamut (which would be suited for such purposes). However, from a practical perspective the input gamut of today’s cameras is large enough for almost everything coming in front of my lenses.


Anyway, I’d still love to hear what Micheal Bevans from tribecalabs has to offer regarding the science part of his product. A nice ab initio explanation would be fine…

Peter

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P.S.: Did you notice my post on sensor design + reference literature before RG forums went down.

No I didn't. Do you have any links for me?

Herman

Equine flagellation aside...

It's interesting to note that Jon Cone sells the plugin on his site. I would imagine Jon can be assumed to know a thing or two about digital imaging.

I have the DCF plugin - Mike was kind enough to send me a copy for review and we exchanged emails about its effects.

I am no colour guru but I know what looks 'good'. My point to Mike was that I thought DCF made normal images 'less good' by making the blue skies too mag. and the greens too yellow. Now it may be that this is more 'accurate', but I personally don't want 'accurate' I want 'good' - not the same thing at all.

Blue skies with too much mag. are buggers to offset print, they are better to be slightly too cyan. However, digital camera do have a tendancy to exaggerate greens and Mike refers to the fluoro green effect. I like the bright greens but it is more accurate to tone them down and make them more yellow. Hence the example posted above is possibly more 'accurate' in the greens, but to my eye, I prefer the brighter green.

I was tempted to get out the GM chart but I thought what's the point? DCF does nothing for my files that I cannot do in PS and, on default, I don't like the effect.

Like Nemo says: get the plugin, check it out, if you don't like it, move on.

One effect that has not been mentioned is the Fill Light slider, a bit like RSP. This works very well with no mystery, and if some beginner had problems with certain tonal adjustments in PS then the plugin is probably worth having for this feature alone.