Colour calibration question

[Graham Mitchell]

Sinar Captureshop has built in colour calibration which work with both the original Gretag Macbeth Colorchecker 24-patch chart and the newer Colorchecker DC chart. Is there a real world difference between the two colour charts? I think I can get the original chart locally but not the DC.



DC:

[Graham Mitchell]

As an aside, most shops seem to be selling the Colorchecker and the Colorchecker SG, but not the DC. Does the SG replace the DC?

[thsinar]

Dear Graham,

I shall answer you in detail tomorrow: I need to get some more information from our technician about specificities and differences of these different charts.

Best regards,
Thierry

As an aside, most shops seem to be selling the Colorchecker and the Colorchecker SG, but not the DC. Does the SG replace the DC?
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[61Dynamic]

The SG and DC are designed for profiling digital cameras. So, if you are profiling your camera to make an ICC profile, then those are the ones you'd get (which it sounds like you are doing).

The real-world difference between the two? The DC has more samples which will result in a better profile.

If however, you are calibrating ACR then all you need is the original since ACR already is calibrated. You only need the grayscale and red, green, and blue squares to tweak the calibration.

[eronald]

As an aside, most shops seem to be selling the Colorchecker and the Colorchecker SG, but not the DC. Does the SG replace the DC?
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The DC was too glossy, people couldn't set it up. The SG is *supposed* to photograph better.

After you've done it, do come back and tell us how useful the profile is.

The accepted wisdom is that camera profiles are  only predictably useful in the illumination conditions under which they were made, but I have found that sometimes a profile can be really good. It will be interesting to see how *you* fare.

Edmund

[Graham Mitchell]

I might have a job coming up shooting a lot of oil paintings, and colour calibration will be essential.

I realise that calibration only really works for the lighting in which it was made. The Sinar calibration seems so simple that it's something I could redo any time colour accuracy is needed. That's not a problem.

As for trying the SG card, I can't do that because the Sinar software is not set up for it. Perhaps this is coming in an update?

It sounds like I should go for the Colorchecker now and wait for the new Exposure software, which I hope will support SG.

Thanks for the replies so far, and Thierry I look forward to anything you might have to add.

[BJNY]

DC: 8 glossy patches, the rest are as matte as the original ColorChecker.
SG: all patches are semi-gloss.

[thsinar]

Dear Graham,

I've got detailled information about the 3 different Gretag/Macbeth Color Charts.

The "old" Color Checker with 24 Patch has too less patches to calibrate Digital backs accurately. That is why Gretag introduced the 240 Patch DC Color Checker. It improves the calibration although this DC Color Checker has its own "problems":

- the patches distribution in the LAB colour space is not so good and regular.
- the neutral patches lead to some problems with polarized light.
- the glossy patches lead to problems when the chart is not lit correctly (reflections).

Therefore Gretag introduced later the SG Color Checker:

- The number of patches has been reduced in comparison to the 240 DC one, but the distribution of the patches is by far better.
- In addition, a particular attention has been put on the "skintones".
- the Semi-Gloss (SG) surface allows a high contrast, without the problems of light reflections.
- The neutral patches have been improved as well.

This makes the Gretag SG Color Checker the best to create a profile for a digital back. Captureshop allows the use of the SG Color Checker. For the eMotion backs you have to proceed the following way:

- You have to work in tethered mode and shoot an image of this color checker with CS

- All while the "Color Managment" in CS is deactivated/switched off (Captureshop ---> Capture Panel ---> Input Profile ---> Color Management Off)

- The image has then to be exported from Captureshop and taken over by any profiling software (like Profile Maker from Gretag Macbeth) to create the new back profile

-  it is advicable to export the image with a "LINEAR" curve, and NOT with one of the "Default"/"Standard" curves. This will make sure that the contrast of the chart are matched to the "must-be" values (White at about 245, Black at about 24)

- the new created profile can then be imported through the "Input Profile" Plugin (in the "Capture" panel, under "Input Profile", WITH the Sinarback CONNECTED

Best regards,
Thierry

Sinar Captureshop has built in colour calibration which work with both the original Gretag Macbeth Colorchecker 24-patch chart and the newer Colorchecker DC chart. Is there a real world difference between the two colour charts? I think I can get the original chart locally but not the DC.



DC:


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[digitaldog]

The SG has a wider color gamut so the resulting profiles will have a higher color gamut. Digital cameras don't have a color gamut; what you place in front of the sensor does. One of the problems in trying to profile them too. A wider gamut target will produce a wider gamut profile but that doesn't mean it's anything like what you'll eventually point the sensor at.

The 24 patch target was never designed for building profiles but rather as a color reference. If you're making profiles, aside from tweaking LR or Camera raw, use the SG.

[Graham Mitchell]

Thanks for the replies everyone. It sounds as though the SG chart and a third party profiler is the way to go.

[ericstaud]

The Gretag input profiles are much smaller than the canned P45 profiles.  I don't know what real world difference there is though.  My monitor is only showing me sRGB, and I have not made any prints from the images created with these new profiles.

[eronald]

Thanks for the replies everyone. It sounds as though the SG chart and a third party profiler is the way to go.
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You could shoot a test under realistic conditions with the SG, and get me or Andrew to run the profiles for you. There used to be two engines on the market, Monaco Profiler and Gretag Profile Maker Pro, and I guess both I and Andrew, and most other consultants have access to both. They are not identical in their renderings.

I know that profiling sometimes works very well, because a decent number of Leica M8 users are using my C1 profiles.

[a href=\"http://web.mac.com/colorconsult/iWeb/Leica%20M8%20ICC%20Profiles/Welcome.html]http://web.mac.com/colorconsult/iWeb/Leica...es/Welcome.html[/url]

Edmund

[Fred Ragland]

...get me or Andrew to run the profiles for you...
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Shouldn't this "consultant" who sees himself on a par with the leading color expert in our industry be advertising in the For Sale thread?

[digitaldog]

I don't build camera profiles.

[eronald]

Shouldn't this "consultant" who sees himself on a par with the leading color expert in our industry be advertising in the For Sale thread?
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 What's going on here ? Are personal attacks of use to anyone ?

 Foto-z should have someone run an image through whatever profile engines he is thinking of buying, so he gets an idea what they can do. I'm not advertising: I'm not a dealer, and running a file isn't something you get paid for - I've already done it for free in the past for a few users of this forum.

 There are a great number of competent people in this industry, and Andrew is certainly of a much greater standing than I am, as his excellent book demonstrates.

Edmund