I needed to make a replacement set of bellows for the half plate/5x7 Lancaster Instantograph I'm restoring. I'd never tried to do anything like this before but it came out pretty nice I think. I didn't skimp on the materials, they are very robust as I used a double layer construction, the inner layer is rubberised blackout material for lining curtains, one side is white rubber, the other is black velveteen. The outer layer is red leatherette. Each of the four sides has 21 cardboard stiffener pieces. The folds are 20mm, the stiffeners are 15mm wide, cutting 84 stiffeners then gluing them with impact adhesive to the inner material was rather tedious and time consuming. The two layers are laminated together with a generous layer of impact adhesive (red Evostik) and I placed the seam of the inner on the opposite side to the seam of the outer, so the bellows are extremely strong, I doubt there will ever be any risk of holes or leaks in this thing, it's built to last.