Adjust color

When a printing company adjusts color...what/how do they do it? I assume if you do your own soft-proofing, you don't want them adjusting your colors...right/wrong?

chauncey wrote in post #16051316
When a printing company adjusts color...what/how do they do it?

I'd assume they still use the "Grey Universe" principle that was used for ages in the commercial printing of color negative film, and is still the basis for auto WB (although the algorithms are more sophisticated today). It is based on the assumption that if you average all the color values in a "standard" photo the result will be grey. If that average is not grey, the channels are adjusted to bring it to grey. This works acceptably well most of the time as long as the deviation from grey is not too great. But send them a shot of a girl in a blue dress posed with a cloudless sky as the background and the machine will make her look like a freshly boiled lobster. An operator sees a preview of the "color corrected" image and is supposed to catch the screw ups and do a manual correction, but if his mind wanders ....

chauncey wrote in post #16051316
When a printing company adjusts color...what/how do they do it? I assume if you do your own soft-proofing, you don't want them adjusting your colors...right/wrong?

If you can correctly use the term "soft-proofing" in a sentence, you don't need the printing company to do color correction for you.

The "standard wisdom" would be to tell them to turn off "auto correction". It's important, though, to be "confident" in your own process and system (as in color management).

I always advise folks to "try out" a printer/service by running some basic tests and tweaking your images (using soft-proofing and provided profiles if available) before committing to more serious/large/spendy prints.