I understand the title to my question is very vague, but bare with me, I think I can make it a bit more precise in the question body.
Recently my mother was asking for help with digitizing a large set of photographs her partner has - tens of thousands of the things, that need to be digitized so they can be sent to book publishers and possibly other types of clients. So I needed to work out how much space she'd need, which raised the question of how high quality the scans would need to be.
That's just an example situation, my question is a bit broader than that: in general, in which industries and situations is quality the most important? One thing I was curious about was what file formats are typically used. Personally I see no visible difference between a 100% quality JPEG and lossless file, but how do professionals feel about that? Is there every a situation where that minute difference becomes important? If so, is it just being overly fastidious, or does it genuinely matter?
Recently, I also heard about photography sessions running into the hundreds of gigabytes. That just blows my mind, wouldn't the images need to be hundreds of megs each? What would ever make them that large?
I hope my question isn't too broad. To break it down into more concrete chunks:
- When does the lossless/high quality lossy distinction matter?
- Can you provide a rough comparison of what's considered an acceptable DPI in various industries/situations, or in your particular industry?
- What file formats are typically used? Just JPEG for lossy and PNG for lossless? Or are fancy domain-specific formats preferred? If so, why?