D60 ETC ICM-profiles (long!)

Started May 12, 2002 | Discussions thread
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Magne Nilsen Senior Member • Posts: 1,120
D60 ETC ICM-profiles (long!)

Most of the time I find my D60 to be so close to the quoted sRGB color space that I shouldn't bother with any special ICM-profiles. On the D30 special profiles were needed since its color gamut was not close enough to any of the standard working spaces. This was true for both RAW and for JPEG formats. On the D60 I feel Canons RAW converter is so close to creating the same color gamut as the JPEGs that I don't bother looking into special profiles or curves for RAW shooting.

IMHO the only problematic color is red. Normally not a big problem, but in some situations it's visibly to much "off" from what it should be. I see the problem mostly in portraits situations where skin colors are involved, and in some products shots where I "know" what the colors should be like. My perceived experience is that reds gets to much Yellow, they should have more Magenta instead. Or - instead of the Reds going towards Green, they should rather be going towards Blue.

The D60 has a parameter tweak that is meant to compensate for this; Color tone 1 and 2, but IMHO this is just a + - 3 Hue shift that affects all colors. Skin colors can become better - but then other colors suffer. The exact same effect can be achieved in PS in seconds.

I've seen examples of users assigning Bruce RGB, but that's really just an sRGB with a larger gamut, and it doesn't correct the reds, it just make all colors appear "richer".
I've looked at two attempts on the net for D60 color profiles;
1: Mark Tuckers nonlinear icm-profile:

http://www.marktucker.com/d60/d60.tucker.nonlinear.16b.sit that shifts the reds towords magenta but they become oversaturated and too intense.

2: Wojteks JPEG non-linear profile version 1.6 here: http://aboutdigicam.com/ that adds more green and blue to the red to flatten the reds - but IMHO ends up with a too flat and boring red.

Both these profiles also try to adjust general contrast. I've tried to profile the D60 myself and it is not easy to get anything better than plain sRGB. On top of that it's very boring and time consuming Here's a JPEG recording of the Kodak Q-60R1 (2000:06) chart done with the D60 for anyone interested:
http://genji.image.pbase.com/u10/magne/upload/2005017.d60q60full480.jpg

So...

I started playing with a simpler approach, I just wanted to alter the r/g/b mapping inside the color rectangle without messing with the white point or any tonal adjustments. So I created 2 batches each of 10 Gamut-mappers based on sRGBs r/g/b XYZ points inside the color rectangle and keeping the same white point at D65 and a gamma of 2,2. From the first batch just one survived D60 ETC-4, and from the second batch 2 profiles survived; D60 ETC-1 and D60 ETC-2.

You can download them here:
http://home.online.no/~etc.etc/artimages/D60-Etc-ICMs1.zip

Here is the gamut mapping of them compared to sRGB:

Usage for all 3 profiles:
1 - Assign relevant profile.
2 - Convert from assigned color space to working color space.
(They can be used as working spaces - I would not recommend that)

Image helper for the following descriptions:

ETC-4: Meet the D60 version of D100s Color Mode III "sRGB with stronger greens and blues for colorful landscapes" Really stronger greens and blues with the reds at the same level and position as in sRGB. Brings back the D30s hot green grass and saturated blue sky without the hue errors. BUT: for portraits or "correct colors" you should do a Saturation -15 after converting to your working color space.

ETC-1: A variation of ETC-4 where red is mapped into what I feel is its correct gamut point. As a consequence it will flatten the yellows and magentas a little, and for portraits or "correct colors" you should do a Saturation -10 after converting to your working color space.

ETC-2: This really is sRGB with red mapped into what I feel is its correct gamut point. For some portraits you still might want to decrease Master saturation a little, but now the 3 gamut points at least are in balance, so this should not introduce hue errors any more.

Better profiles could be made with the right amount of passion and work, but I'm afraid it will always involve contrast and gamma changes too - I don't like that.

So do they work? Most of the time I think so. A profile will never correct a wrong white balance, and some of the changes applied here - especially with ETC-2, are subtle, so don't expect miracles. Here's a sample from a childrens chair with the typical problematic red color. ETC-2 is exactly as the real object!

Try them out! All comments are welcomed - preferably in this thread.
--
Magne

Below are all variations on the different ICMs discussed compared to the 7 "pure" color bars from the Q60 chart - the left column always shows the "correct" rgb values for my chart according to Kodak:

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