I'm working on a project and I'm hoping to achieve the best results possible when printing. Following various guidelines I found online I started scanning at 16 bit per channel to get a higher color grading, however it is most likely I would only be able to print in 8 bit per channel.
If I open a 16 bit file in photoshop and change it 8 bit to match the printer would I loose any quality? I can't see the difference myself but I wonder if that's the case.
if I have files at 16 bit should I re-scan them accordingly or can I just change it in Photoshop without worrying about quality loss?
If you have a 16bpc file and you’re sending it out to be printed, you follow the file specifications the printing service requires. So if they require an 8bpc JPEG file, you convert it to that.
If you’re printing directly, you don’t have to convert the file for printing, because Photoshop can do it on the fly for you. If the printer driver is one of the few that can receive 16bpc files directly, then in the Print dialog box in Photoshop, the Send 16-Bit Data option will be available and you can select it. However, you should know that many printing experts say it’s hard to see if Send 16-Bit Data makes any visible difference, maybe in part because of the limited dynamic range of print. So I leave it disabled.
If the printer driver can’t handle 16 bits per channel files directly, or if the file is not 16bpc, then the Send 16-Bit Data option will be disabled, and the file will always be sent at 8bpc.
Selecting Send 16-Bit Data sends more data, so it may take longer to print, and may require more free storage space for the temporary spool file.
Also, it may not be obvious or easy to explain, but there can be strong reasons to scan at 16 bit and do all your corrections at 16 bit even if the final result is 8 bit. You keep more accuracy as you change and enhance the picture, reducing the chance of "banding", and save 16 bit for future use. Only then convert to an 8 bit version if you need to, keeping both.