Digital Rebel FAQ / Discuss

Doug Pardee says:

If you're shooting in Raw, it doesn't matter. If you're shooting in JPEG, keep reading.

There's no easy answer to the question of which color space to use. There have been hundreds or maybe thousands of discussions on the point.

Here are the basic facts:

1) A color space defines how colors are represented in numeric form. Most color photos are in "8-bit" form such as JPEG, where colors consist of three numbers ranging from 0-255—one number for red, one for green, and one for blue. A color space defines what the color 130/56/219 means (as an example). That RGB value represents different colors in different color spaces.

2) One of the effects of a color space is that it defines a gamut—the maximum range of colors: what colors 255/0/0, 0/255/0, and 0/0/255 are. Colors that are beyond those values are called out of gamut because there's no way to have a value less than 0 or more than 255 in an 8-bit format like JPEG.

3) sRGB is going to be the easiest to use, because just about everything can deal with sRGB. For most casual and light amateur uses, sRGB is the way to go. I use sRGB myself because I stick my CF cards right into the kiosk at the minilab down at Target, and minilabs pretty much only support sRGB. Also, any pictures that you post on the Web (like here on Flickr) should be in sRGB because that's what browsers expect.

4) Adobe RGB is able to represent some deeper greens and blue-greens (cyans), and some brighter reds and oranges than sRGB can. We say that it has a slightly larger gamut. That sounds like a Good Thing. However, most computer screens cannot show those additional colors, Web browsers will screw up those pictures (showing them as overbright and with washed-out color) because browsers assume that all JPEGs are sRGB, and most minilab printers cannot print the additional colors even if they did know how to process something other than sRGB. The primary value of Adobe RGB is for self-printing on a quality printer, and even then you need to remember when you're editing that unless you have an expensive monitor you can't see the full range of color in your pictures. Successfully using Adobe RGB requires spending a lot of time learning about color spaces, profiles, rendering intents, etc. Color management is not for the faint of heart. :-)

5) For reasons that aren't at all clear to me, Canon has chosen to render colors differently between sRGB and Adobe RGB. If you select Adobe RGB on a Canon DSLR, you'll get relatively accurate color capture. If you select sRGB, you'll get "punchier" colors with noticeably brighter blues and purples, somewhat brighter greens and yellows, and (on some cameras) slightly deeper reds. In theory if you took a shot in Adobe RGB and converted it to sRGB, it'd look the same as an sRGB shot but that's not the case with Canon DSLRs (at least the Digic-based ones).

6) On the original Digital Rebel (300D), no color space tag is included in the actual JPEG file. You have to remember which photos were taken in Adobe RGB mode, and manually "assign" the Adobe RGB color space when you process those photo files. This is not an issue for the XT/350D, XTi/400D, XSi/450D, T1i/500D, and XS/1000D.

Now for my personal opinion: Adobe RGB is nice, but the advantage that you gain is small compared to the complications and effort involved. If you're that serious about your photos, you probably should be shooting in Raw. And as I said at the beginning, if you're shooting Raw the color space that you select in the camera doesn't matter.

(Edited 2 July 2007: added point about DReb/300D files not being tagged with color space.)
Originally posted at 8:38PM, 16 January 2007 PDT (permalink)
Doug Pardee edited this topic 30 months ago.