Flattening files - does it matter?

Do you need to flatten a file for printing, or can you send it with layers? For final prints I usually dupe my master file, flatten, size, sharpen, do a last cleanup pass, and print. However, with smaller test prints I might just send the layered files to print.

If you send a layered file to print, how does the file get turned into something the printer can print? I’m guessing it makes a temporary flattened file that the print driver spools and sends to print.

I’ve never seen a difference in print quality or appearance between layered and flat files, just processing time in Print-Tool.

You don’t.

I do too because sometimes the masters are freaking huuuge.

Same.

Tif files are actually a folder w/ the flattened version + a photoshop layered file beside it. The non-Adobe apps just use the flattened version. This is why TIFF is so huge. PSD files are interpreted by MacOS because Apple pays Adobe for the full api. Either way it works.

best,
Walker

Thanks Walker! That is very helpful.