Photography is hard enough on its own if you’re a picky photographer or very critical of your work, it’s even harder to deal with color if you’re color blind. Color blindness isn’t uncommon, but what it means is often mistaken. By saying I’m colorblind I’m not saying I can’t see color, I can tell the sky is blue and the grass is green. Obviously there are people who can’t see any color, but far more common are people who have difficulty telling certain colors apart. Generally speaking, the term color blind does more to confuse than it does to enlighten. Unfortunately it’s the accepted term for people both completely blind to color and color deficient (like myself).
There are three basic kinds:
- Completely monochromatic vision, where two or three of the photo pigments in your eyes cones are missing.
- Dichromacy occurs when you’re missing a pigment: red (protanopia), green (deuteranopia) or blue (tritanopia).
- Anomalies occur where one of your cone pigments isn’t quite right and doesn’t have the right spectral sensitivity, resulting in a reduction of your ability to discriminate colors. The red and green pigments are the most similar so it is easier for differences in them to impact the ability to distinguish colors. Protanomaly occurs when you have a slightly shifted red sensitivity, deuteranomaly (what I have) occurs when your green sensitivity isn’t quite right. Tritanomaly is uncommon (as is tritanopia) and this occurs when your blue pigment isn’t right. This makes blue-yellow discrimination difficult.
As a deuteranomalous person, I can see red and green, but I often have a great deal of difficulty telling some hues apart. To go even further, in spite of this, my overall color discrimination of all hues is rather poor, not just red-green.
Testing color vision
One test of color vision is to use the Ishihara test with the colored dots that are devised to show certain shapes. They can be made to show numbers for a person with regular vision and appear blank for someone with varying types of color blindness, however the tables can also be turned. They can be made to show shapes for color blind people but not color-normal. You’ve probably all seen these, but chances are if you have normal vision, you’ve never seen one you can’t see the shape in.
Another, and more in-depth test, is the Farnsworth-Munsell 100 hue test (which has 85 hues, don’t ask me why they call it 100 hue). This is a series of color chips with a number on the other side and it’s in four sets. You organize them by logical procession from one end of the set to the other. On one side you could have a peach color, on the other it would be green and a color normal person could organize them with little error. You tabulate the score by recording the sum of the differences between the number on a patch and the numbers on the back of the two adjacent to it. Since they’re numbered sequentially a perfect score is a 2 for every color. The more you screw up, the higher your score goes.
Notice the scale on the radius of the chart (the numbers labeling the concentric rings). My friend with good color vision never exceeds 4 while I go past 10. My two trials don’t even match each other in where I screw up, and if I did more trials it wouldn’t improve. My friend did better his second time through which is normal for most people after they loosen up and get in to the test a little more.
To detect varying types of color vision defects, certain patterns are looked for in these plots. If you have a strong deviation at the 10 and 4 o’clock positions, you’re deuteranomalous. I exhibit that behavior (as I should) but the rest of my scores aren’t very good either because even for other colors, my ability to tell them apart is pretty poor.
What does it mean?
For someone like me, this makes playing with color really tricky. I always enjoyed B&W photography (and some day I hope I can set up a darkroom and get back in to it), but color has always been hard. Shooting film is tricky for color since every film has a preset preference for a certain white balance. Films like Velvia which are easily excitable and don’t perform well in unideal lighting conditions are hard for me to work with. Obviously I can’t print color in an enlarger very well, so when I do I have often had to rely on someone else to steer the colors in the right direction.
Computers make color much easier for me, but it’s still not perfect. If you give someone with normal color vision a calibrated monitor and some photos to work with, they can zip through them adjusting color temperature, saturation and playing with hues and never think twice about it. If you give me the same task you can’t expect the same quality results. Calibration helps in a gross scale, but fine tuning for me (other than gray scale/contrast and brightness levels) is mostly a moot issue because my descrimination is poor enough to make me an unreliable judge of color anyway.
Before digital cameras I scanned film quite a bit. 35mm, medium format and large format negatives and slides when scanned can produce excellent results (and huge files). If someone with normal color vision wants to adjust the white balance, they just do it. If I want to adjust it I have to find something in the scene that should be neutral and adjust the overall balance of the scene until that object has uniform RGB values in the color picker. If I want to push the color of something a certain way, I have to use what I know about the RGB values of colors to adjust something to the values I have in my head, and hope they are the right colors. It is very easy for that to go horribly wrong, and a nice pink sunset could turn green or I could suck green out of trees by adding too much magenta.
I jumped feet first in to digital photography a couple years ago and haven’t looked back because setting white balance is a snap with digital cameras. I can also adjust in raw conversion later using color temperatures based on lighting conditions or the time of day. I can’t say the same for dealing with film. It is easier to please my eyes because I am unable to see differences that might be obvious to the average observer, but I still try to get things “right.”
In the end
I can do a lot of the things everyone else does, but often with less confidence and often with inconsistent results. There are areas I often tip-toe around like playing with colors to enhance saturation or change the tones of certain objects in a photograph. I could just convert everything to B&W through the channel mixer and have a lot of fun that way, but I like color photographs, and screwed up as they may sometimes look and I’m not going to stop taking them or stop tinkering with them. I continue to play the balance between what looks right to me and what looks right to everyone else.
Last modified: August 6, 2009