On May 17, 2004, at 2:16 AM, William Robb wrote:
There is really no such thing as a "profile" in this instance. Really, find out what colour spaces the lab recognizes, and choose the one that is best for you. If they can't tell you, then the default profile to use is sRGB.
In the case of my lab, they say to use the sRGB colour space. But that is no use in soft proofing as its only a device-independent colour space so it contains no information about the tonal response and colour gamut of the paper and printing process.
That's mostly taken care of within the machine though; supposedly we're able to just throw them anything in sRGB and the machine will handle it. My assumption is that sRGB has a smaller gamut than the paper itself, so that any in-sRGB-gamut colour you send them in your file will be reproduced on the paper. OTOH it would mean that the colour space is the limiting factor, which is not necessarily a good thing.
I'm not too worried about this as the results I've had have been quite good despite some gamut clipping (particularly blues and yellows) as my source images exceed the limits of sRGB. If I was looking for fine-art prints I wouldn't be going to a high-volume minilab in the first place. And I don't want to get too carried away by the theory if I don't have any control over the implementation ;)
I just had a quick play with one of my notoriously difficult files, soft-proofing to sRGB. The result looks interesting and I might try making appropriate adjustments and having a print made.
Another lab here insists on Pro Photo RGB (they have a Lambda machine). I haven't tried this lab yet but that colour space is wide enough to drive a double-decker bus through. I'd be hesitant to send them anything short of a 48-bit file as I like my photos to actually show a bit of tonality.
Cheers,
- Dave
http://www.digistar.com/~dmann/
