CMYK or process color is the color mode used by commercial printing equipment to create full-color graphics and images. The process involves combining varying amounts of cyan (C), magenta (M), yellow (Y), and black (K-for “key”) ink to produce the full spectrum of color. The other common color mode – RGB color – uses three colors – red (R), green (G), and blue (B) – to create a full-color effect.
RGB is the color mode used by computer monitors, digital cameras, and TVs. Varying levels of red, green, and blue light combine to create the images which appear on the screen. That’s why web-based images are created in RGB color mode.
When designing your artwork for print, we recommend starting with CMYK color mode. This will help ensure your images and background colors look good from the start. Of course, you can create your artwork in RGB and then either convert it yourself or have us convert it to CMYK for you after the fact. However, because the two color modes are so different, such conversions are never just a simple flip of the switch.
While most colors translate pretty well from one color mode to the other, subtle color shifting is common when converting from RGB to CMYK (and vice versa), requiring some manual adjustments to get things just right. For example, many software programs will translate a 100% blue RGB value into a CMYK color that looks more purple than blue. Such changes will need to be accounted for if you start with an RGB color mode and then convert to CMYK later on.
If you send us files that use RGB color, we will convert your files to CMYK before printing them. In such cases, we recommend you view a printed proof before we complete your order, so you can see how the converted colors will appear in print.
For information on setting up your files to use CMYK color, visit our application-specific instruction pages.
Converting Images in Adobe Photoshop
If you’re using images from a digital camera, chances are those photos use RGB color. Here are the steps to take to convert an RGB image to CMYK color using Adobe Photoshop.
- Create a copy of your original image and open both in Photoshop. This will provide you with a point of reference to look back on once you’ve converted your image to CMYK.
- Choose the copy you want to convert and select Image > Mode > CMYK Color from the main toolbar at the top of the screen. This will convert the image to CMYK.
- Referring back to your original image (still in RGB mode), adjust the colors as needed. In most cases, Photoshop will do a good job converting the file, but subtle adjustments may be needed.