Video screens create colors by varying the intensity of red, green, and blue light at each pixel. In a standard digital video signal, each of these values can range from 0 to 255. For example, a pixel might have values of R=150, G=100, B=50, producing a light brown color.

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Since people with red-green color blindness have difficulty detecting differences between the amount of red and green in a color, ColorblindTV uses a targeted approach that directly magnifies this difference.

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Simply adding more red to the entire image would be counterproductive. Although this would increase the difference between red and green in some colors, it would decrease it in others. This would  distort the overall color balance. Greens would shift toward yellow, yellows toward orange, and whites and blues would take on a reddish hue. Adding green would cause similar distortions in the opposite direction. Increasing both red and green would not improve red-green contrast at all.

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Instead, ColorblindTV examines the red and green values of each individual pixel and calculates the difference between them. A percentage of this difference is then added to whichever value is larger and subtracted from whichever is smaller.

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For example, consider a light brown pixel:

R = 150, G = 100, B = 50

The difference between red and green is 50. If the enhancement were set to 50%, the adjustment would be 25. Because red is larger than green, 25 would be added to red and subtracted from green:

Before: R = 150, G = 100, B = 50 — light brown
After: R = 175, G = 75, B = 50 — a redder brown

The red-green difference has increased from 50 to 100.

Notice that the red and green values are changed by equal amounts in opposite directions. Red increases by 25 while green decreases by 25. Their sum therefore remains unchanged:

Before: R + G = 150 + 100 = 250
After: R + G = 175 + 75 = 250

Thus, the red-green contrast is increased without changing the combined red and green intensity.

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The same process works in the opposite direction for a predominantly green color. Consider an olive green pixel:

Before: R = 100, G = 150, B = 50 — olive green
After: R = 75, G = 175, B = 50 — a greener, more vivid green

Again, the red-green difference increases from 50 to 100, while the combined red and green value remains unchanged.

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Equally important, a color with equal amounts of red and green is not changed by the red-green enhancement. For example:

Before: R = 150, G = 150, B = 50 — mustard yellow
After: R = 150, G = 150, B = 50 — mustard yellow

When red and green are equal, there is no red-green difference for a person with color blindness to have difficulty seeing. There is therefore no reason to increase that difference. Because the red-green difference is zero, ColorblindTV makes no red-green adjustment. This helps prevent colors such as yellows, whites, and grays from acquiring an unwanted red or green tint.

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ColorblindTV also applies a separate adjustment to the blue component of each pixel. Rather than comparing blue with either red or green individually, it compares blue with the average of the red and green values. When a difference is present, that difference can also be increased.

For example, consider a green pixel:

R = 70, G = 140, B = 80

The average of red and green is 105, so blue, at 80, is 25 below that average. Increasing this difference can lower the blue value while leaving the green value itself unchanged. The resulting color can appear greener and more vivid even though no additional green has been added.

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This blue adjustment complements the primary red-green enhancement. It can increase the visual separation and vividness of colors without simply increasing the saturation of the entire image. Neutral colors remain protected: when red and green are equal, no red-green enhancement occurs, and when blue also equals their value, as in whites and grays, no blue enhancement occurs either.

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As a result, ColorblindTV selectively increases differences among the color components that help distinguish colors from one another. Its primary purpose is to magnify red-green differences that are difficult for people with red-green color vision deficiencies to detect, while the complementary blue adjustment can further improve the distinctness and vividness of the resulting colors.