There seems to be a lot of baloney going around about LED lighting and color rendition. Namely that when using LEDs of various colors you can still reliably see all the colors of the spectrum. Frequently I read an advertisement for a single color LED light that claims to still give the user the ability to read a map. Reading a map is a good test since a map is something that is very important to read accurately and contains a lot of colors.

Now, the key word in reading maps is "accurately". If the ink on the map matches the color of the LED (Let's say, red ink and red LED), that color will show up as white - effectively disappearing into the background. What about the rest of the colors? They'll show up in various shades of single color "gray" fading to black. Don't believe it? Let's see how a map of Orlando shows up under various colored LEDs.

All of the views are the same size and cover the same area, so what you see (or don't see) in one view is visible in another is the same place.

For reference, here is the map under normal lighting:

Now let's see if you can make out the same details with Monochromatic LED light...