Preferably, use a perforating wheel to cut,
but in lack of such, you can cut along lines with a scalpel,
taking care to not cut all the way to the edge.
We have been organising the prints of Edlef, my dad, and thought they should find homes. This one is ""Silverskog"" (Silver Forest), printed in 1973. The gray-ish areas you see are silver ink. It's dazzling I find!