Macbeth Colour Checker and Slide Film

[tomczak]

Does anyone have access to colorimetric data (or calibrated scan) of Macbeth Colour Checker patches rendered on slide films? Cheers!

[HanSch]

What exactly do you need? I have no data of the Macbeth Colour Checker patches, but a long time ago I purchased IT8 calibration slides from Wolf Faust (for slide scanners). The batches are produced with very tight tolerances and each batch is measured by Faust with calibrated equipment.
So if you are interested in IT8 patches rendered on various Kodak, Fuji and Agfa slide films, I can provide you with the data (Lab, Lch, XYZ)

Han.

[tomczak]

Thanks Han,

I mentioned Macbeth, mostly because I have it and know its characteristics. I'm not sure if I understand IT8 targets: the colorimetry of the targets on various materials is measured, but what's known about the original colours under known illuminant?

My intention is to figure out how a slide film distorts colors. For instance, with Makbeth the colour data are known or can be calculated at various illuminants, then if such standard target is photographed on a slide film and colours measured (or scanned on calibrated scanner to a know colour space), one can figure out what the slide alone is doing to colours. How does it work with IT8?

Cheers and many thanks!

[keithrj]

Here is a great web page with detailed analysis of the MacBeth colorchecker including downloads etc.

http://www.babelcolor.com/main_level/ColorChecker.htm

I have not gone through this in detail but it looks the most comprehensive set of information I have seen so far.

[HanSch]

Maciej,

I don't know how the IT8 slides were created. If I can find out how they were produced it is possible to create ICC profiles for the various slide brands based on the measured data (I need the input colorimetric data). Then you can do a soft proofing with these profiles to figure out how the slide "distorts" colors.
I can e-mail Wolf Faust for the input data, if you're interested.

[tomczak]

Thanks Han,

I emailed Wolf Faust a few days ago about it, but the answer was that his targets won't be useful in finding what slide films do to colours. I'm still not sure why or how his targets are produced or if there is a single colorimetric, measurable IT8 standard from which slide rendition can be made and difference assessed. Cheers.

[tomczak]

Keith, I also asked Danny Pascale of BableColour, he's got various measurements of Macbeth, but not on films. His article on and spreadsheet on the updated chart values (and how it's done) is worth reading. Cheers.