Darkroom printing with borders

I like the way prints look with a small black border around the image, like this:

Darkroom print hanging to dry

Darkroom print hanging to dry

I know some people file their negative holders but that means no cropping and there's no way I'm precise enough with framing to not crop about 90% of my images at least a little.

What I did instead is cut a piece of poster board ever so slightly smaller than my usual print size. I place this over the image after making the initial exposure and do one more quick 5-second exposure for the border.

This works, but it's difficult getting the board lined up evenly. For now, I'm writing that off as providing uniqueness but I'm still looking for something better.

I taped the edges with dark tape so it's easier to see in the dark.

I almost always print 6"x8" on 8"x10" paper, so this will be fine most of the time. If anyone has a better technique, I'd love to hear about it.

Scanned black and white darkroom print of power tower and tree branches

Scanned 8x10 silver gelatin print. I'm testing my homemade border-maker mask. It's a bit hard to get even.