Not sure where to post this: I use Prophoto RGB as my color space when working on images and printing them. When I down size them and convert to JPGs for web use, I sometimes leave the images as Prophoto RGB and sometimes I convert to sRGB color space. Lately I have been leaving the images as Prophoto, but when posted here on the forums, and on my own web site, I note the images are not as color saturated as they appear on my color managed PC at home. Any advice what space to use for web JPGs? Any help much appreciated.
ProPhoto RGB is a 16 bit-per-component color space ... you should never use it for JPEG images as they are 8 bit-per-component files. Using ProPhoto RGB on JPEG files can cause some pretty odd imaging problems as the numbers "fold" around the limits of the 8 bit integer boundaries.
On the other hand, ProPhoto RGB is the RIGHT color space for editing as it has plenty of room to do adjustments and transformations without clipping. Be sure you are editing 16bit files with ProPhoto RGB. If your masters are 8bit per channel, either use Adobe RGB (1998) as your working color space for editing, or promote the masters to 16bit per channel before editing.
For display on the web, the correct color space to use is sRGB. It is the standard that all web browsers expect when rendering photos even in the absence of a color profile.
When you're outputting files from your 16bit-per-component edit masters for the web, the correct procedure to use is as follows:
0- Save your master file.
1- Convert color space from ProPhoto RGB to sRGB
2- Convert component depth from 16-bit to 8-bit
3- Save a
copy to web file in JPEG format
The basic rule is to always convert the color space before you convert the component depth.
G