Color Space

Color Space (pdf)

Here I will address a technical issue with respect to color.

Color space defines the range of colors contained in an image file. Typically you will receive images from a photographer in one of two color spaces, Adobe RGB or sRGB. Adobe RGB contains a broader range of colors than sRGB and is typically used for images that are going to print; sRGB contains a narrower color range and is the color space for the web.

There is much end user confusion/lack of knowledge about color space, often resulting in less than optimal color in final output whether in print or on the web. My personal experience with legal clients over the years varies widely with respect to this issue.

For a while I was supplying clients with two sets of files, one in the Adobe RGB color space for print and one in the sRGB color space for web. Now, I assess the level of knowledge of the responsible staff at a firm and make a judgement as to what to do. If staff understands the basic concept, is willing, and has the wherewithal to use the different sets of files appropriately, I will supply files in both color spaces. Otherwise I will supply one set of files in the sRGB color space to avoid confusion. For 99% of the photographic needs for law firms, the sRGB color space is more than adequate for both print and web. If, however, a set of images is solely destined for print, I recommend Adobe RGB.

The major part of the problem, which should simplify over time, is that only a couple of web browsers are capable of color management, i.e. the ability to recognize an image’s color space and to display its intended color. Apple’s Safari, Firefox 3, and Internet Explorer 4 can (in IE4 you need to turn this on as a preference). Except for Safari, which has had this capability for some time, it is only the latest versions of browsers that are color managed and, so, for color to be displayed accurately in older legacy versions, files need to be in the sRGB color space. Adobe RGB in a non color managed browser looks flat and dull. See below.

adobe rgb

This color management issue is further compounded by staff attrition at a firm. As the responsible staff, versed in these issues, moves on to a position elsewhere, the practical information/knowledge needed to manage the photo files is lost in the hustle bustle of the moving on.

One goal of this site is to provide a knowledge base for handling photo files. The information here is intended as a long-term reference to help you understand the basics of managing your photo files for their various uses. If you do not find answers to your questions, please feel free to email me and I will try to clearly answer them.

The easiest way to ensure that an image in the Adobe RGB space will be displayed properly in a web browser is to use the "Save for Web & Devices" command in the the file menu of the menu bar of Photoshop. In the dialog box which presents itself, select jpeg from the drop down menu with a quality of 100, the optimized box checked, then hit save and save to the appropriate folder. This makes the necessary conversion for proper display. Alternately you can do the following, though your file size will be somewhat larger:

Basic steps for color space conversion from Adobe RGB to sRGB in Photoshop:

Open image

Edit: Convert to Profile (not Assign Profile)

Set Destination Space to Profile: sRGB IEC61966-2.1

Use settings of:

Engine: [Adobe (ACE)]

Intent: Perceptual

Check: Use Black Point Compensation

Check: Use Dither

Click OK

Save

In older versions of Photoshop (prior to CS2):

Open image

Image: Mode: Convert to Profile (not Assign Profile)