Originally posted by marcdsgn I'm not too sure about that. Speaking from the commercial prepress POV, if you're a professional who cares about the final print, then you should be shooting RAW, or the closest thing your camera provides to RAW format. Printing presses are very unforgiving to JPG images, and any subtle changes that you decide may need to be made to your image once you've received your proofs for review, can only be done from an image that has retained the maximum amount of original data from the RAW image.
JPGs are mere ghosts of the original image and the stripped-back data is practically useless to work with at a professional post-processing level. There may be professionals out there who are happy with the limited post-processing abilities that JPG provides, but any professional who has an understanding of commercial printing standards will (or should!) always post-process from RAW images.
Then, for best result with commercial printers, provide TIF or EPS conversions. Not JPG.
Well there are two areas at play here: The photographer; and the printing process. It's not about whether professionals make mistakes when taking a shot or not, it's about compensating for camera-to-printer data translation. In other words: Being able to tweak that brilliant shot so it looks just as brilliant when printed.
I also work prepress in a commercial shop and do a ton of full color design. I use jpgs, tifs and psd files for the photos. As soon as I get the jpegs they are opened in Photoshop and saved as tifs. Then all prepress is done to that file and saved. The jpeg is never saved back to itself because of the data loss. The original save is okay just don't save back to itself. Most photographers are not going to press with their stuff however. Most are going to photo output wich has a much higher gamut than any press has. I run 300 line stuff with waterless inks and although it looks good (actually it looks great) it still won't approach the photo quality.
Also, taking a tif into illustrator or any other program then saving as an eps it's still a bitmap image. EPS is vector art such as what illustrator puts out. Tifs can't really be made into vector. It's still bitmap.