I have been watching almost the complete series of videos and particularly that related to the Print Module (Video 45). Jeff: you explain there about the use of jpg as output, but you don't say too much about Profile (you just change sRGB to Adobe RGB....can one use a particular paper profile for a certain printer? or with jpg it is useless?). Furthermore, about File Resolution: if my lab uses an Epson 9900, should I leave 300 ppi as you set in the video or upsampling my image to say 720 ppi, as you advise in a previous video?. As I can't afford a pro printer like the 9900, I prefer to use a custom lab, and I would like to get the best from my file when sending it to the lab (they began to use the 9900 and Canson papers).
By the way: the videos are amazing!....I bought in the past the Kelby and Evening books, but videos are sometimes more educational than books. Congratulations! great job!!
I would ask the lab first. Say how you have the files natively (for example 16 bit prophoto xx by yy pixels) and ask how they want them to delivered should they print it at a certain size. A prolab will give you an answer. You may expect that they know how to print and if they don't start looking at another (or try to educate them if you're brave).