Why everyone with the .eps files?!
Can we PLEASE PLEASE PLEASE kill postscript files? They are bloated, and can do strange things in transparency effects.
I can understand if you are working in corel...or quark...but if you are working in exclusively in adobe apps...PDF!
It also depends on your RIP. We use Caldera, and retain ALL vector data so we can control spot colors at the RIP.
Just say NO to global color corrections! LOL
We send only pdfs to our rip. Just like all pdfs...all jpegs are not equal. It really depends on how big your output is, and if upsampling is required. We run grand format dye sub (126" wide), and many jpegs are unsuitable for print. It's compression artifacts...the ones you DONT see on your monitor, like in the highlights and white areas of the image. Anytime we get a jpeg of say a product shot with a white backdrop, there are almost ALWAYS a plethora of near white pixels that show up at larger sizes. We end up having to scour and mask out all of the white. PSD files will always give you the cleanest, most safely compressed output. LZW gives artifacts...jpegs give artifacts...
People talk about lossless compression...it may exist on wikipedia, but not in the real world. I actually had a client send me a link to lzw tifs on Wikipedia!!!
The analogy I use when shunning jpegs and compressed tifs is this:
Take a 1 liter bottle of coca cola. Pour it into a 12 oz can, and discard the rest.
Now pour what's in the can back into the 1 liter bottle. Pixels work the same way.
Again, if you are not printing extremely large this can be moot. We've found if it is graphics based...like fonts and effects...jpegs are NOT the way to go.
Let your RIP translate it from a vector source, or a native .psd or pdf from Photoshop.
Jpegs from a high quality digital camera are different. As long as they haven't been jacked with and compressed externally, and reinterpreted they typically work great.
We don't accept pdf files from clients for production art...we generate them all in house to ensure no nasty surprises arise.