How to flatten old diplomas?
Depends what material the diplomas are made of. I don’t know much about vellum, pulp paper is my thing. If it IS paper and it is brittle you will need to consult a professional paper conservator. (They may need to humidify the paper before unrolling) If the paper is relatively sturdy you may unroll it yourself. Please do not roll the paper the oppose way as this puts undue tension on the paper. You will need two boards that are larger that the paper. Preferably us laminated board: even a small grain may imprint on the paper. Press the paper between the boards using small weights, one at each corner and one in the centre. Leave for three or four days.
