I'd forgotten I have a small set of frames similar to David Brown's. I take it that top left image isn't one of yours David

These thinner edged frames are great for smaller prints and sets of images.

In talking about framing something we are overlooking is consistency in the matting, and getting the balance right if showing images from a mixture of film formats.

I'd had a standard that I maintained for nearly 20 years, but then had a re-think and change about 5 or 6 years ago. This meant reprinting many images for a large exhibition rather than using existing prints from 2 other exhibition sets alongside fresh prints. Part of the decision was the demise of Agfa papers and switching to Polywarmtone and a desire for continuity & tonal coherence.

Now I've settled on standard print sizes from each of the formats I use (6x6, 6x9, 6x17, 5x4/10x8) that work together when in 20x16 frames, and corresponding sizes for my larger frames.

Frames are too expensive to chop & change so decisions have an effect on how you show work for some time.