I went to an Ansel Adams workshop in Yosemite National Park in 1977. (That's
my Nikon F2 on the tripod at right). He was an amazing fellow. He could tell
the length of a shutter exposure by just listening to its sound; "That's
1/10th of a second."
The portfolio that I brought was 11x14 prints mounted on black matte boards -- standard contest fare by photojournalists in that era.
The fine art photographer faculty at the workshop, who mount on white matte boards, looked at my portfolio on the black board and read into it that there was something very deep and sinister about the photos being on black boards.
I thought it was just a "f8 and be there" kind of thing. It's amazing how photographs invoke different feelings in different people.