7.67.52015-05-06

Color Management and Matching

Since PlanetPress Design displays on your screen, in PDFs and on printers, there are a few things to keep in mind if you want the colors you see to be the same as the colors your print, and if you want to match a specific, exact color.

Monitor display VS Printing

• The monitor produces the color you see on-screen with light while the printer produces color with pigment. The set of colors, or gamut, you can produce with light is not identical to the set you can produce with pigment. Thus there are colors you can produce on a monitor and not on a printer, and vice-versa.
• The monitor uses three primary colors of light (red, green, blue) to produce all the colors you see on-screen. It mixes different amounts of each of the primaries to produce a particular color. An on-screen color is specified as three numeric values, the first describing the amount of red, the second the amount of green, and the third the amount of blue light to use to create the color. Thus these are often referred to as RGB (Red Blue Green) colors.
• The printer uses three primary colors of ink (cyan, magenta, yellow) and black to produce all the colors it prints.
• The set of colors you can produce with light (the RGB gamut) is larger than the set of colors you can produce with pigment (the CMYK gamut). Thus monitors can produce more colors than printers.There is a significant overlap between the two gamuts however, and, in those cases, the problem becomes how to match a color that it is possible to create with either light or pigment, on different physical devices.

Representation and control of color in physical devices

The difficulty with physical devices is that none are stable enough to ensure a consistent representation of a given color. Physical devices for our purposes are monitors and printers.

• Monitors The same color can vary across monitors due to factors such as the phosphor specification, the calibration, and the age of the individual monitor. Even on the same monitor the color can change as the monitor ages or loses its calibration. The set of colors a monitor can display (its gamut) can also vary across monitors.
• Printers The same color can also vary across printers or on the same printer due to factors such as the inks a printer uses, the amount of ink in the printer at the time you print, and the physical properties of the paper on which you print.

Colors in PDF Files

When PDF Files are used as resources, either external or internal, some optimization is done. A PDF that contains transparent objects will have the transparency flattened, meaning that the transparent layers will be blended and rasterized.

PlanetPress Suite converts CMYK colours to RGB of all raster images that are not part of a PDF or EPS. It is then preferable to put CMYK images into a PDF or an EPS since they remain untouched through the entire process to avoid colour shifting at printing time.

Output using PDF resources will differ depending on the type of output used. When printing using a Windows Driver, the output goes through the Windows GDI engine, and thus is submitted to some color transformations related, especially, to the Windows color profiles. When printing using Printer Centric or Optimized PostScript Stream, these transformations do not occur.

The difference between PostScript printing and GDI output can be tested outside of PlanetPress. When using Adobe Acrobat, the GDI output is used by default. However, in the File -> Print dialog, if you click on Advanced Settings and select Print as Image, Acrobat will then rasterize the image using its own internal RIP, meaning the PDF color profile is kept as is. This is equivalent to printing in a PostScript format.

Color perception

Our perception of a color can change with variations in the ambient lighting. A color that appears very rich under subdued lighting may appear washed out under bright lighting. Our perception of a color can also change due to the colors that appear alongside it. The same color on two different backgrounds can appear to be two different colors. Finally, two individuals may not see the same color.

To set up color management in PlanetPress Design: 

1. Start PlanetPress Design.
2. From the PlanetPress Design Button, choose Preferences to display the Preferences dialog box.
3. In the Preferences dialog box, expand Behavior, click Color, and set the color management options.
   • Select Color Management Active. Note that you must select this option before you can select the monitor and printer color profiles.
   • Set Monitor Profile to the color profile for the monitor of the computer on which you are running PlanetPress Design.
   • Set Printer Profile to the color profile for the printer on which you intend to execute the document.
4. Click Close.

When you use color management profiles, PlanetPress Design attempts to display the color on your monitor as close with so it is as close as possible to the printed result.

The following limitations apply, however: 

• Since external variables such as lighting, time of day and different users can impact colors, there is no guarantee of the result.
• Changing the color profile does not, in any way, change printed and PDF output colors. It is only and exclusively meant for monitor display.
• Profiles only apply to colors specified within PlanetPress Design such as font colors, backgrounds, shapes and lines. Profiles do not modify the display of images and other "external" resources.