If you are designing graphics for a web page you have to keep in mind to make them also accessible to colorblind persons.

With Photoshop CS4 Adobe introduces soft proofing for color blindness, a great support just for this task.

The new soft proofing filters for color vision deficiency were developed in corporation with the Japanese Color Universal Design, a user-oriented design system, which has been developed in consideration of people with various types of color vision, to allow information to be accurately conveyed to as many individuals as possible.

Adobe Photoshop CS4 supports the following two color blindness filters, which combine the two most common forms of color vision deficiency:

• Protanopia-type (red-blindness)
• Deuteranopia-type (green-blindness)

To determine whether your document is CUD-compliant or not, step through the following three simple steps:

1. Convert the document to RGB color mode, which provides the most accurate soft proofs for color blindness.
2. To simultaneously view the original document and a soft proof, choose Window > Arrange > New Window (optional).
3. Choose View > Proof Setup > Color Blindness, and then choose either Protanopia-type or Deuteranopia-type.

To comply with CUD, you have to check your document in both views.

If you are a graphic/web designer, don’t forget to check your graphics on accessibility for colorblind users. Photoshop CS4 is one of the tool which can help you to fulfill this task—the color blindness simulator Coblis another (online) one. You might find some other helpful tools on my list of 15 Tools If You Are (Not) Colorblind.

Thanks to Jay Kinghorn and his article on Photoshop CS4: Color Blindness Proofing. You can also find more information on color blindness validation at the Adobe Photoshop CS4 accessibility overview.