Trying to understand ICC profiles

Shogo · 07-30-2008, 09:34 AM

I am new to this whole color matching thing and I sent some prints into MPIX to have them printed. I used a huey pro to calibrate my monitor and then sent the pictures in to be printed. They all came back different than what i had expected. The photos I had taken that were saturated had a more neutral look to them and the desaturated photos seemed to look more saturated in the print. I used Adobe RGB and I think Mpix uses SRGB for printing, could this have caused the problem?

Also I'm confused about ICC profiles. I was looking at WHCC.com and I am going to try and send a few pictures there. The website says that when I create an account I can download an ICC profile from their site and use it. Now, my huey pro allows me to save my own ICC profile after calibrating the monitor. So whose ICC profile should I be using, the one huey makes or the one from WHCC? And what is the difference between ICC profiles and color spaces?

davemdsn · 07-30-2008, 10:29 AM

Yes, if you send a photo in aRGB and it gets printed in sRGB without proper conversion it will come out less saturated. You should always send photos to labs in sRGB unless they say otherwise. WHCC does use aRGB.

The ICC profile your Huey makes is just for your monitor. Every device along the pathway needs it's own profile. The profiles you get from WHCC, or any other lab, are for their printers, not your monitor. The printer profiles are made available to you so that you can use the soft-proofing tool in applications like Photoshop, Aperture, and others. You should not set your monitor to that profile, nor should you set your photo file to that profile unless the lab requests it (which is not likely).

Your monitor profile is there to help your monitor display colors accurately. A printer/paper profile is there to help the printer print colors accurately. This is why each device needs it's own profile. The image itself should be in a profile designed for images, like sRGB, aRGB or even ProPhotoRGB. When you work on a photo it is a good idea to work in a large color space like aRGB. When you are ready to send it to a lab you should convert (not assign) the image to sRGB. If you have an app that offers soft-proofing you should also use that tool to see how the image will look when limited to the color space of the printer or paper. If it doesn't change then your colors are within the limits of the printer's color space. If it changes then you have colors that are outside the destination color space.

davemdsn · 07-30-2008, 10:35 AM

One other thing. Mpix does do color correction by default. If you have done everything right and you are sure that your colors and color management is where you want it you need to let them know to not do any correction. It is a question toward the end of the order process. Make sure you read all the pages carefully.

WHCC does not do color correction. They are my favorite lab, but one should be pretty comfortable with color management when using them. If you have all your ducks in a row their prints are the best. If you have missed a step somewhere... well, you get the idea. If they notice a problem they will generally let you know about it.