So I know about the different color space for different purposes (for the most part). sRGB = internet purpose. ProPhoto RGB = high quality prints. This is mainly because of the different in size of color gamut. What I don't understand is 2 things. 1) What makes ProPhoto RGB so good if printers cannot output the colors anyway because it is so big. I mean, most places I go to like Bayphoto and Nations Photolab ask for adobe 1998 AND jpeg rather than TIFF. So if I want to make a great print (we're talking museum quality)...where do I go online? 2) I'm thinking of making some posters with images from illustrator. Vista print asks specifically for the file to be done in CMYK because thats how the printers work with the image. OR they said send it in the natural illustrator.ai file type. after reading this thread (below)and some comments by Andrew Rodney (the apparent kind in this stuff), it seems like the people at vistaprint dont know what they're talking about. Andrew said all printers expect RGB colorspaces, so you need to give it to them. THEN they convert to CMYK http://www.photo.net/digital-darkroom-forum/00YjZ4?start=0 so if some of these people are right, and CMYK is garbage to work in, why is it even available to work in? why would adobe products allow us to work in garbage colorspaces?