Okay, before I start let's assume that I am using a good lens. Not the best lens, but a $1,500 zoom lens. A good one. I am shooting at 100ISO on a Nikon D200. With that in mind, what is the largest size print I can have images PROFESSIONALLY printed before I start to lose quality? I ask because I am working on the pre-production part of what I hope to be an art gallery worthy photo series. I have never worked on this side of things before. My work is pretty much left to the periodicals and 5x7s in a picture frame on someone's desk. Also, what workflow would you use to touch these images up? I import images into Photoshop as Raw, but what would I export them as to take to the printers? I am guessing TIFF or something like that since they need to be uncompressed, and as far as I know JPEG compresses images. Another note, when I say gallery size prints, I am talking like 24"across by 36"down. Or something close (I know that a 5x7 translates perfectly into a 25x35). Thanks for the help in advance. There are a lot of knowledgable people on these forums so i expect to get some good advice back. Thanks.