How to see out-of-gamut colors?

[Derek_Kusiak]

I'm starting to scan my 35mm film (with a Nikon 5000) and I'm trying to get a feel for how well my film's gamut fits into certain color spaces. I'm mostly scanning various negative films with some E6 (mostly Provia and Velvia). The 5000ED lets me scan in a large native color space (an extended Adobe Wide Gaumt RGB) that's guaranteed to contain all the colors the scanner can see. However, I'm not sure my films require such a large space, and I would prefer to use the smallest space I need to avoid imaginary colors and other difficulties.

Is there a tool, preferrably for WinXP, that will let me compare the colors in a specific (profile-embedded) image an to another color space? Can I use Photoshop's out-of-gamut warning mechanism to achieve this by opening a large-space image and soft-proofing to a smaller space, like aRGB?

Thanks.

[AlanRew]

Chromix ColorThink 2 is a good tool for seeing actual image data gamuts and comparing with profile gamuts.

The new Microsoft colour control panel applet can, AFAIK, show profile gamuts, but I don't know whether it can show image gamuts. It needs XP SP2 installed BTW.

If you're scanning Provia & Velvia then you'll need a large colour space, so stick with the Nikon-supplied profile for now. Rather than worry about 'imaginary' colours, it's a good idea to process your images in 16-bit per channel. You won't get any imaginary colours in your scans, of course; I assume you're just worried abiout the efficiency of the working space.

'Real World Color Management' by Bruce Fraser and others is a good book on the practicalities of colour spaces and 16-bit workflow etc.

You may also get good info in this area by posting in the RGB 'Film Scanners' forum.

Regards,

Alan

[John_Luke]

You could simply scan in to EktaSpace PS 5, a gamut developed by Joseph Holmes. Many of the large Tango scan houses like West Coast Imaging use this. Not too big, not too small. I would be careful of the über gamut spaces like ProPhotoRGB because if your colormanagment technique is not of the herculian level you could be creating problems for yourself. I recall the Nikon D1x cameras had a custom space they called Nikon AdobeRGB or something like that. Is that what you were considering?

[Derek_Kusiak]

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I recall the Nikon D1x cameras had a custom space they called Nikon AdobeRGB or something like that. Is that what you were considering?

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Actually the Nikon 5000ED scanner's native color space is what Nikon calls "Wide Gamut RGB (compensated)". Basically it's the normal Adobe Wide Gamut RGB space with a non-linear extension that captures additional information in the blue part of the gamut, which is where Wide Gamut RGB is weakest.

[Derek_Kusiak]

Thanks for the suggestions. ColorThink seems cool, though the trial version is pretty crippled so I can't plot image gamuts or use my own profiles. But it's not very expensive, so I may give it a whirl just the same.

I'll check out Bruce Fraser's book. It was one of his articles that got me thinking about bigger spaces in the first place.

And incidentally, I posted in the Film Scanners forum first but got no replies. You guys have been much more helpful.

[ QUOTE ]
Chromix ColorThink 2 is a good tool for seeing actual image data gamuts and comparing with profile gamuts.

The new Microsoft colour control panel applet can, AFAIK, show profile gamuts, but I don't know whether it can show image gamuts. It needs XP SP2 installed BTW.

If you're scanning Provia & Velvia then you'll need a large colour space, so stick with the Nikon-supplied profile for now. Rather than worry about 'imaginary' colours, it's a good idea to process your images in 16-bit per channel. You won't get any imaginary colours in your scans, of course; I assume you're just worried abiout the efficiency of the working space.

'Real World Color Management' by Bruce Fraser and others is a good book on the practicalities of colour spaces and 16-bit workflow etc.

You may also get good info in this area by posting in the RGB 'Film Scanners' forum.

Regards,

Alan

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