Hi, to add a few more factors: 1) paper that is too old or stored in hot conditions can become "fogged" - meaning it will be overall gray in tone. Check by developing a sheet straight out the box, without exposing it. If after processing it is a mottled gray, it means it is too old.
2) A safelight that is too bright can also fog your photo, most notably making your bright tones gray.

Jon