Pro RGB...really?

Started Nov 8, 2012 | Discussions thread
technoid
Senior MemberPosts: 1,295
Like?
Re: Pro RGB...really?
In reply to rpenmanparker, Nov 9, 2012

I have mixed feelings about ProPhotoRGB. On the one hand, as others have pointed out, it has a wider gamut and can encompass vritually all of what a camera's sensors can capture. OTOH, it far exceeds what any monitor can do let alone monitors that are only sRGB capable. The latter means that you can easily create colors that can't be produced on your monitor. If you have a lot of highly saturated colors it is quite easy to create a very pleasing image that wouldn't look right at all on a larger gamut monitor.  And then there is the issue of printing. While all colors within a printer's gamut are within ProPhoto's gamut, the opposite is far from true. At least with printers it's easy to check where in an image colors are out of gamut (View proof in Photoshop) and one should always check this before printing.  Fortunately, most (though not all) images one encounters do not exceed sRGB and of the ones that do, they almost always fall within Adobe RGB. The best reason to use ProPhoto RGB is the certainty that you will be able to work with any color your printer is capable of printing and this is not true of sRGB or Adobe RGB where printers often have gamuts that exceed them in certain areas. Most typically in cyans in the midrange of luminousity. However, doing so requires more care to make sure either that colors you see on the screen when adjusting images are within the gamut your particular monitor or, alternatively, that you have some other way to determine the correct color is being used, a path few tread.

One other factor using ProPhotoRGB is that you should always work in 16 bit mode. Because each adjacent hue is further apart in ProPhoto, 8 bit values increase the risk of artifacts when you have areas of gradual color shifts such as in skies.

Here's an example where a camera can capture an image that won't even fit into ProPhoto. Sunlight exiting a prism being split into the color spectrum. The colors are actually right at the edge of the classic horseshoe gamut. They are within the gamut of the camera's sensor and hence RAW files, but exceed every working colorspace. Their true colors are unprintable and unviewable on monitors without a great deal of desaturation. ProPhoto can represent them better than other spaces but they still have to be displayed on an actual monitor.

Until you are comfortable with colorspaces (and they can sure seem confusing) I would recommend sticking with sRGB or AdobeRGB if you have a profiled, wide gamut monitor.

Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow