Or, why does my stuff look different on screen versus on paper?
Every designer searches for "truth in color," whether it's finding the right blue to evoke feelings of trust and stability or choosing a green that says a company is forward thinking, environmentally-aware, but also serious, not playful.
Recently I was working on a project that was governed by a pre-existing corporate style guide. For those who don't know, corporate standards, graphic standards, brand guidelines and similar descriptors, refer to a document that delineates important aspects of a company's image. Some of the elements it usually addresses include use of the logo; fonts for print and web; graphic elements such as bands and gradients and shapes (such as rounded corners instead of sharp ones); whether the corporate style is to use illustrations versus photos, and corporate/secondary/tertiary color palettes.
During the course of working on this project, the client noticed how different something looks on screen compared to when it is printed on paper. This phenomena is the difference between how the eye looks at emitted light and reflected light.
Emitted color is projected to the viewer through the computer screen, just as it is with a television monitor. All colors viewed this way are composed of 3 colors: red, green and blue. This color model is referred to as "RGB" color, and it is the model used for all colors seen on the web. RGB is also the model used for traditional color film negatives.
Reflected color is color viewed on a surface, whether it is a magazine, bus card, billboard or brochure. Even backlit posters and banners are still produced as reflected color. The model used is cyan, magenta, yellow and black, or CMYK. CMYK is also known as "4-color process," or "full color". If you use a look at the Sunday comics section and you'll be able to see CMYK dots. In addition to CMYK, there is also Hexachrome color, which uses CMYK plus orange and green. Hexachrome expands the color possibilities that can be achieved in full-color printing.
Another ink model used for reflected color is called a "spot" color. Spot colors are pure colors that are mixed with different pigment formulas, sort of like when you have paint mixed to paint a wall. Commonly used spot color sources include Pantone, Toyo and Focoltone, Trumatch plus custom ink mixes. When a job, such as a 2-color business card, is printed — often it is printed with 2 pure spot colors.
Spot colors can be converted to CMYK, but because CMYK is limited in its ability to interpret color pigments, it's not always possible to convert spot to process with identical results. Also at play is the surface upon which the color appears. A shiny surface will appear more bright and saturated than a dull one.
SO...getting back to that pesky client.
Because emitted color and reflected color DO look different, even though he had a corporate color palette, he wanted to specify different colors to be used in print and web. For print, he wanted to specify a PMS color PLUS a CMYK build that was different than the formula normally used for the conversion. Next, he wanted to specify an even different RGB formula for the web. His thinking was that he'd be able to control the look of his color across various media.
It's a nice idea, but in reality, different monitors (LCD, CRT) have different white points (brightnesses) and color capabilities, and every monitor is calibrated slightly differently, just as different color printers have varying color profiles and produce different output. One of my clients LOVED the way Epson color layouts looked and was always a little disappointed because commercial (professional) offset printing couldn't deliver the same results. Just as monitors display colors differently, when you provide a PDF to someone and allow them to print it out, you've essentially lost control over the quality of the color output.
Especially now when so many people are uninformed about how to even evaluate good color, and based on the inability to control color, my recommendation is to choose colors from a widely accepted color library (such as Pantone or Toyo), gearing it to the dominant use—whether web-based or print. But always be aware of what happens in various models (spot, process or RGB) and check out what it looks like on uncoated, matte and coated surfaces. This extra effort will help avoid unpleasant surprises, and It's the only way I know to "idiot proof" and, as much as possible, preserve the integrity of intent.