Colour visual impairment is very common affecting around 8% of males and 1% of females of those with European ancestry, and those affected see the world differently to non-affected people and have a significantly reduced color vision palette.
Most people probably will not know they are color blind but one can easily test yourself via this online test that Enchroma provides.
How does color blindness occur?
There are 3 types of cone cells in the retina each of which detect a different range of colours, blue “S” cones, red “L” cones and green “M” cones (S, L, M refer to short, medium and long wavelengths of light).
The OPN1LW and OPN1MW genes (responsible for red and green cones respectively) are located on the X chromosome, whereas the OPN1SW for blue cones is on a different autosomal chromosome.
The far majority of color blind people have Deutan blindness (6% of all males and 0.4% of females of European descent have a partial form called Deuteranomaly ) which is inherited from the X chromosome, so any male with this gene will be affected, but females generally require both X chromosomes with the defective gene to have color impairment. If a mother has only one chromosome affected, 50% of her sons will be affected and 50% of her daughters will be carriers. If a father has the gene, he will not pass it to his sons but ALL of his daughters will be carriers.
In addition, 1% of males have no green receptors which is called Deuteranopia in which greens look like dark purples , while 1% of males and 0.01% of females have the milder red receptor deficiency called Protanomaly and another 1% of males have no red receptors which is called Protanopia in which reds look like dark greens. Extremely rarely (1 in 100,000 people) have an inherited blue cone deficiency called Tritanopia which may also be acquired due to various eye conditions and can cause confusion between blue versus green and red from purple.
There are other extremely rare forms of severe color blindness such as blue cone monochromatism in which both red and green cones are defective, and Achromatopsia in which there is no color vision but only shades of grey.
If one has an extreme form of colour blindness, this will usually prevent you passing your driver’s license testing and you should give up on most commercial photography other than B&W photography.
How does Deuteranomaly affect you as a photographer?
Those with Deuteranomaly will usually have most difficulty seeing certain shades of pinks (which may look grey) and purples (which may look blue) while other hues in the reds, yellows, oranges and brown range may look similar especially in low light.
This means that when one is editing photos, they may over-emphasize certain hues such as pinks which can be problematic when editing skin tones, and when styling a fashion shoot, the colours may well be not as complimentary to each other as they perceive.
How can a Deutan mitigate these issues?
Some companies sell expensive glasses designed to “improve color vision” in those with milder forms such as Deutans. An example is Enchroma who makes glasses that filter out certain wavelengths to “reduce confusion” and reduce the overlap of colour detection between the red and green cones.
Unfortunately, whilst these glasses may provide a more colorfully vivid experience of sunsets by allowing one to see more pink and purple hues, a study has shown they do not provide a more “normal” visual perception, nor do they correct your vision to pass color blindness tests.
However, there is help at hand for those photographers editing their photos or viewing digital images in the form of software correction.
Windows 10 seems to do an excellent job of correcting color vision for digital displays – just go to Settings:Ease of Access: Color Filters and turn on Color Filters and select the deficiency, for a deutan this would be the deuteranopia setting. Once this is set you may even pass the online test that Enchroma provides and be given “normal vision”.
Apple iOS devices have a similar setting but in my experience is doesn’t seem to work as it makes the reds appear pink when they should be red despite of which intensity you set and when re-running the online Enchroma test I now get a Protan result irrespective of intensity suggesting there is a problem. The setting is found at Settings:General:Accessibility:Display Accommodations:Colour Filters then you can turn this on and then select which type and the intensity whilst viewing a color palette.
More information on my wikipedia.