To determine the dominate wavelength (DWL) of a GamColor filter, draw a straight line from the coordinates of the light source you intend to use, (2848 Kelvin for incandescent or 5400 Kelvin for daylight sources), through the coordinates of the selected color to the curved edge of the CIE Chromaticity Map. You may see, in older text, Kelvin indicated as degrees Kelvin or °K. "Degrees Kelvin" and °K are obsolete. Kelvin is now designated in this manner, 2848K, or 2848 Kelvin.

The dominant wavelength indicates the specific hue that the eye perceives from the combination of lightwaves which are present. DWL does not indicate how saturated the color is. The closer to the curved edge, the purer and darker the color will be. Closer to the light source the color will appear lighter and less saturated. Colors whose coordinates fall closer to the light source will have a higher percentage of light transmission.

Lavender and purple colors are a mixture of red and blue and they do not exist as individual spectrum colors. To determine the DWL of a color that falls in the lavender region, draw a line from the coordinates of the light source through the color filter coordinates to the (straight) 'purple' line. Continue the line in the opposite direction to the spectral curve, the color's DWL will be specified as a complementary color or a minus (571c).

You may use the GamColor CIE Chromaticity Map to select color filters and to visualize the colors you can achieve by blending them together in two separate instruments. After selecting the colors, draw a straight line between the two sets of coordinates. You may mix the color that appears along that line. Referring to your GamColor swatchbook, you can visualize those colors and determine the range that you will have when mixing the two selected colors.

Three color mixing. Select three GamColors, and using their coordinates, form a triangle. All the colors within that triangle can be blended harmoniously using the three main colors you have chosen. All of the GamColor coordinates that fall within the triangle can be reviewed in your swatchbook, and you can actually see many of the colors that you will be able to blend. This is an excellent tool to help choose colors for lighting a cyclorama. Keep in mind that you cannot create colors that fall outside the triangle. If the lighting range for your production require colors that are not within the triangle, you may have to make a different choice for your triangle of GamColor.