Color blindness affects some 5% of the population, rendering certain colors identical to them. We all remember the color perception tests from our younger days, but how would your images look to someone with one of the three different varieties of color blindness? Etre, a company that specializes in usability and accessibility has put together a "Colour Blindness Simulator", which lets you upload some of your own images and see how they render to people with the condition.
While you can only upload a 1000x1000 image of up to 100kb, you can see some of the results in the image above. That's one of the most garish of my own photographs that I could find on short notice, with the original on the left, and then run through filters to simulate protanopia and tritanopia.
Not only are there different types of color blindness, but also different severities of the condition — and this tool will only show one. But as a photographer, it's intriguing to see how certain people might see your images without you even realizing it.
There are other similar tools available, including one which you can use online, or as an iOS or Android app. And as one commenter pointed out, some versions of Photoshop allow you to do this, too.
I'm very curious if we have any color blind photographers in our readership, and how their condition influences their photography. If you have deuteranopia (or any of the other types of color blindness), how does it influence how you shoot?