Forum: Photoshop


Subject: Colour Depth, Bit and usefullness

Macsen opened this issue on Feb 10, 2005 ยท 3 posts


Macsen posted Thu, 10 February 2005 at 9:17 AM

Hi.

I've been scanning all my images since I got SilverFast as CMYK-16bit, but recently some people started complaining that the images are too big and have a lot of extra data that should not be scanned... I'm a graphical designer/photographer (dont check gallery, never updated) and usually scan the images for storage and later quick retrieval.

My question is this.. for this kind of job, what would be more usefull, RGB or CMYK and 8bit pr 16bit per channel? some programs cannot show thumbnails of CMYK16 (thumbs plus) so I get a generic icon... of course the negatives could later be retrieved for professional use and re-scanned... but that's something that I would like to avoid... so... what colour model for what?

RGB-8?, RGB-16?, CMYK-8?, CMYK-16?

Thanks in advance

Rick


lundqvist posted Thu, 10 February 2005 at 9:48 AM

I guess always scan in 16-bit and downsample copies on demand for clients who wish to use 8bit per channel? 8bit receives wider support at present of course, but holding master copies with the highest precision should make rescanning unnecessary.


crocodilian posted Tue, 22 February 2005 at 10:41 PM

A couple of points: scanners scan in RGB-- CMYK is a generated format that's bigger and typically is targetted at the color profile of a specific output device. So you should be saving RGB for future use, and convert to CMYK when and if you need to print from it again. The scanner itself doesn "see" CMYK, so this info is "invented" by the conversion software-- you gain nothing saving it this way. If your scanner is truly scanning at 16 bits, as opposed to software interpolating 8 bits to 16, then you should save this way, because its more information. A number of digital asset managment systems will automatically produce reduced size versions of your source files and place them in designated places. . .Cumulus, Extensis Portfolio, PhototoWeb --- there are many solutions for the problem of storing and repurposing files at multiple resolutions, formats, whatever. . .search on "digital asset management" and you'll find many systems. . .