I don't know what u mean by primary purpose light colors but if you just asking for primary colors these are the only ones.
Hey there!!
You click on the image and got up to the top of the screen and click on "object - arrange - send to back" NOT "SEND BACKWARD".
Hope this helps. c:
Display is important because it helps someone who is viewing a photograph to identify what is being captured in the photograph. If there is "bad display", someone viewing the photograph wouldn't be able to enjoy the image without being distracted by something like bad photo quality or blurriness.