Use your mobile camera
Take a picture with the camera, move the cursor to the item you want to know the color of, the color name is printed in plain text on the top of the screen. You can also use any of your existing pictures that you have in your iPhone.
Set the white balance
It is best if you have something white in the same image. Eg copypaper, a countertop, etc. Then you have the option to set it as a white reference point. This offsets all the colors as much as the white differed from pure white.
If you have a red tone in the image due to incorrect white balance in the camera, its now compensated. Even dark scenes are better analyzed if we can set a white reference. The result is never better than the camera's quality and / or the photographer's accuracy. Example, a blurry image can produce an incorrect result, or a dark image without a white reference give dark colors, although the colors are bright.