Hi everyone. Here is a gray test pattern that is used in setting up monitors and projectors as well as video cameras. It works equally well as a post processing aid by showing you what "neutral", which is gray, black, and white, looks like on your monitor. These gray bars contain equal amounts of red, green, and blue. There is no color to them whatsoever. You can keep this little image open in your editing software as a reference. If you have any neutral areas in your image (black to gray to white), you can compare them with this reference image and see if they match. If your neutral areas have any color to them, it means that the color balance of the image is off and you can correct accordingly. By using this type of reference, the color errors of your monitor, if any, can be accounted for.
BTW, not saying that every image should have neutral grays, but unless you are shooting in the warm light of sunrise or sunset and want to preserve that warm look, you will want to have neutral blacks, grays, and whites.