From the conclusion:


(emphasis mine)

I'm having hard time parsing this - although it doesn't create better profiles, it's still a must-have?

As I haven't calibrated my cameras or films, just my monitor and printer, I'm unfamiliar with that end of the calibrated workflow. Does the above mean that the Colorchecker is must-have in certain situations, for example when there's no profile (as is the case with S90), or under some specific or difficult lighting situations?

And even if that's the case, it sounds like it's a "good-to-have" rather than "must-have."

Hi,

I'd suggest that it is useful for:

1) Calibrating the DSLR/MFDB for a certain set of light conditions
2) Calibrating the DSLR/MFDB for individual variations

The software can be downloaded for free and I see no reason it would not work with any recent Color Checker (I tried and it works). The Passport itself solves the problem of handling the Color Checker which is quite fragile.

I have used color checkers for a long time and it's one of those products which actually would make my pictures better would I not forget to use them. A "WhiBal" card is another one. I noticed that using a Whibal just makes for better colors, but I always forget.

Best regards
Erik

What I found interesting was the comparison pic. Yes the scarf may now be red but did you see those skin tones? Yeuch. Specifically Adobe Yeuch. Why on earth can't they get all that red out of the skin tones, C1 seems to do fine...

Hi,

Well, the idea is to have correct colors, not necessarily same as pleasant colors. DNG profile editor allows for tweaking colors.

If you are shooting a product it may be a requirement that certain colors are reproduced faithfully, in that case using color checker to calibrate colors may be useful.



Best regards
Erik

I've been using the colour chart since DNG Profile Editor first came out and now have the passport. Doesn't change the fact that skin colours are nowhere near as red as adobe's rendition would have you believe.

I was confused also. I intended to post the same question, but decided to give it a little more thought before posting. I'm still confused.

Reading most of the article, one can understand the importance of having a camera profile that gives accurate color rendition in particular lighting conditions, so something like the Colorchecker makes sense. But if the Adobe dual illuminant approach already yields better results (does it?) then what is the point?

I generally like the color adjustments that the Passport software makes, but have noticed that it, as well as the DNG Profile editor profiles, both suffer from overly saturated caucasian skin tones. The second patch from the top left seems way over saturated in profiles from both. The very same image of the chart used to generate profiles reads with 5% more red than it should when viewed in LR with the newly assigned profile. DNG Profile Editor can handle broader adjustments, but is difficult to desaturate that color range without draining the saturation from the orange and red chips.

Sounds comparable to some films being more faithful for Caucasian skin tones than others, and vice versa for Asian.

Hi,

Lets assume that we have an illumination that does not correspond to black body emissive spectrum, like a flourescent lamp, and profiles adjusted to light may make sense.

Best regards
Erik

Hi Erik, yes, a good point. A related question is this: Suppose you photograph a person under a fluorescent lamp. In real life, suppose the lamp is making the skin have a (not very nice) greenish tint. Is the job of a color profile to (1) reproduce the scene as-is, i.e., the reproduction would be a picture of a person with greenish cheeks? or (2) to reproduce the scene as people want them to appear, e.g., the reproduction shows a person with "normal-looking" cheeks, as if they were photographed under natural daylight, instead of the fluorescent lamp?

Hi Eric,

I guess it's more 2) than 1). The profile cannot now about the spectrum of light. I assume that profiles are built about continous illuminants.

Here in the EU we start phasing out incandescent lamps, replacing them with energy saving flourescent bulbs. So viewing conditions get worse.

Best regards
Erik

It is a similar situation in the USA. I have tried building lamp-specific profiles, with good success, but these get to be rather specific to the spectrum of the light. In general the CFL-based profiles do not work so well under natural daylight, nor the other way around. Not surprising.

If you look at the spikeyness of the spectral distribution of most artificial sources, you will quickly see how overall color temperature is only a part of the equation. I learned about how deceptive color temperature is for evaluating the spectral distribution of light when growing live coral under artificial light. Two lamps may read identical in color temperature when it is averaged, but one may be almost entirely missing the part of the spectrum that corresponds to it's measured color temperature (by having two spikes on either side of it), and the other may have just the middle part of the spectrum that corresponds to the color temperature with little on either side. That's asking a lot of a profile to extrapolate that type of information to be useful with significantly different (and uneven) illumination. That is one of the great benefits of a quick and easy profile creation system, too, in that it makes it easy to profile frequently for specific situations.

The job of a profile is to ensure accurate colors under a given lighting condition. If accurate colors are not desired for whatever reason, that's a job for the Profile Editor or PS' color adjustment tools.

BTW, a good fluorescent profile isn't going to give a greenish cast to skin tones. The Color Checker patches are going to have a greenish cast before the profile is applied, so if the profile is good, the profile corrections needed to make the Color Checker patches have the right colors will fix the skin tones as well.

I have a Digital Color Checker SG card (which has 96 color patches instead of 24) used for camera profiling in EyeOne Match. Are there any plans to make a version of the profiling software that can use the Color Checker SG as an alternative to the Color Checker? It would probably make better profiles...

With the DNG Profile Editor, using the Chart Wizard generates an adjustment for each patch in the chart. There's nothing to say you have to stick with those exact adjustments, you can tweak them to get more pleasing results. So if the second patch of the top row is over-saturated, tweak the adjustment for that patch to desaturate it a bit. I take a similar approach to get more pleasing results for the landscape images I shoot. The default chart-wizard profile will results in grass, leaves and other foliage being more yellowish than I would like, so I tweak the relevant patch adjustments to give my landscapes more pleasing foliage. If the Passport software doesn't have this capability (I haven't tried it), then that would be a big advantage in favor of the DNG Profile Editor IMHO.

That's one thing I would have liked more info on in the review, is the capabilities of the Passport software versus the DNG Profile Editor, and maybe a comparison of profiles created by each.

I did a quick check of the profiles for the Nikon D3 using Imatest Colorcheck. I compared the Adobe Standard Profile, a profile made from the Adobe Standard using the DNG editor automated method, and the Passport derived profile. Illumination was from a Solux panel and I used the ACR defaults except for a black point of zero.

Adobe Std profile:
Click to view attachment

DNG Editor profile:
Click to view attachment

Passport Profile:
Click to view attachment

Composite DNG Profile and Passport Profile. The DNG profile is overlain with the Passport profile with reduced opacity.:
Click to view attachment

All of the profiles demonstrate increased saturation (chroma), but this is not a serious fault, since saturation can easily be reduced with the ACR sliders or in Photoshop. With increased saturation, the a* and b* are increased proportionally so that the vector shown by Imatest points to the white point in the center of the graph. A color error is more serious, since it is much more difficult to adjust and the changes in a* and b* are not proportional and the vector does not point to the white point in the center of the graph.

For the all important skin tones (patch 2), the DNG profile gives the best results. Dark skin is patch 1, blue sky is patch 3, and foliage is patch 4. The differences are not great and are summarized below:
Click to view attachment

Could you provide a plain-English summary for the laypeople here, please

Hi,

He compared the Color Checker Passport software generated DNG profile with the Adobe DNG Profile Editor generated profile and Adobe Standard Profile (for the camera in Question). Illumination was with Solux lamps (which emit near D50 illumination, with continuus spectra). The images were compared with Imatest which is a well regarded software for testing photographic equipment.

His findings are:

1) All exagerate contrast (slightly)
2) They are pretty close
3) Caucasian skin tone (#2 patch on CC card ) is pretty close to reference values)

I made a similar test without involving Adobe DNG Profile Editor and had similar results.

Best regards
Erik

Thanks. So the question still remains: what (if any) use there is for this hundred dollar "must buy" product if the results are similar to the Adobe profiles?

See: Neil Snape's post at http://luminous-landscape.com/forum/index....showtopic=39142 It's far more than just a one time camera profiler.

Thanks, that did make sense - so in effect it's a more accurate and complete version of a grey card to get colors correct in tough lighting conditions, not only white point?

Feppe,

I'd just point out two things:

1) The software is actually free. A Color Checker Card is all you need.
2) There are some situations were this my be of interest
a) You camera doesn´t correspond to Adobe Standard profile
Your illumination is not like Illuminant A and Illuminant D50 on which Adobe Profiles are based. A good example may be flourescent illumination sometimes used for product photography or electronic flash. Neither have well behaved spectra but contains spikes. With a special profile based on your illumination you may get better results than with a standard profile.

I'd suggest that the Adobe DNG Profile editor may be more useful, because the profiles can be tweaked (for taste).

In addition to what Eric said, you should look at the Imatest Web Site for more detailed documentation and an explanation of terms.

In addition to what Eric pointed out, the Passport does include a small version of a Colorchecker and white balance card in a small portable package with a plastic case. The full sized Colorchecker is about the the size of letter paper (8.5 X 11 inches) and is mounted on cardboard; it is rather delicate and not something you would want to carry in the field. In addition to the large Colorchecker, there is also a miniature Colorchecker that some carry in the field and the version included in the Passport appears to be similar to the smaller version. I don't know if it is mounted on cardboard or on a more durable plastic backing.

For my purposes, I carry a WhiBal card in the field. This card is of a durable plastic, not cardboard and can withstand field use. If you need to make profiles in the field and don't have a white balance card, I would think that the Passport would be useful, but I would not consider it must have for my type of photography. I wonder if the white balance card of durable plastic.

Thanks!

I wanted to add that but forgot!

Erik

there is a full Passport size white balance card as part of it along with a number of patches that allow you to create custom white balances as well. I've found this to be quite useful out in the field when lighting conditions change.

If you haven't already got a color checker chart the passport package is very good value. It also offers a few extra tweaks for white balancing that aren't available on the normal CC chart.

For what it's worth my own, less scientific, findings are similar to others here; Not much difference between the Adobe editor and the Passport software, but the passport software profiles seem a little too saturated. I'll use the Adobe editor as first choice.

It seems a shame that XRite failed to add the option of using the digitalSG chart for building profiles. It would be interesting to know if the extra gamut and samples would have given better profiles.

+1. Having additional data points certainly couldn't hurt profile quality...