8.8.  Display Filters

Revision History
Revision $Revision: 2405 $ 2008-01-18 lexa

This command shows a dialog window when executed. This window can be used to manage the display filters and their options. Display filters are not to be confused with the filters in the filters-menu. Display filters do not alter the image data, but only one display of it. You can image display filters like big panes before your screen. They change your perception of the image. This can be useful for things like soft proofing prints, controlling the color management but also simulation of color deficient vision.

The images you create, we hope, will be seen by many people on many different systems. The image which looks so wonderful on your screen may look somewhat different to people with sight deficiencies or on a screen with different settings from yours. Some information might not even be visible.

Color Deficiency Type

In this drop-down menu you can select from among:

Protanopia (insensitivity to red)

Do not be afraid of this odd name. It is made up from three Greek roots: “op” for eye, vision; “an” for negation; “proto” for first, the first color in the RGB Color System. So, protanopia is a visual deficiency of the color red. It's the well-known daltonism (red-green color blindness).

Protanopia is actually more complex than this; a person with this problem cannot see either red or green, although he is still sensitive to yellow and blue. In addition, he has a loss of luminance perception and the hues shift toward the short wavelengths.

Deuteranopia (insensivity to green)

With deuteranopia, the person has a deficiency in green vision. Deuteranopia is actually like protanopia, because the person has a loss of red and green perception, but he has no luminance loss or hue shift.

Tritanopia (insensitivity to blue)

With tritanopia, the person is deficient in blue and yellow perception, although he is still sensitive to red and green. He lacks some perception of luminance, and the hues shift toward the long wavelengths.

Here, we are back in the medical domain. “Contrast Sensitivity” is the capacity of the visual system to distinguish slight differences in contrast. Some people with cataracts (which means that the lens has opaque crystals that scatter light over the retina) or retinal disease (for instance, due to diabetes, which destroys the rods and cones) have a deficiency in sensitivity to contrast: for example, they would have difficulties distinguishing spots on a dress.

If you are interested in this subject, you can browse the Web for “contrast sensitivity”.

This filter allows to enable the GIMP color management for each image window. To learn more about the color management in GIMP, please read Section 1, “ Color Management in GIMP ”.