#bc that's the thinnest and stretchiest of all

[oidheadh-con-culainn]

Question from a tanner re: parchment: do you know why it's bendy enough to make into books? Because rawhide tends to break rather than bend (see: drums with which break), and parchment should just be rawhide with the top layer of skin scraped / sanded off. Is it that top layer that makes rawhide stiffer? Or do parchment makers somehow work on it to make it more pliant?

i don't know much about rawhide so it's a little hard for me to compare the processes but i would say it's probably a mixture of materials and processing! firstly materials: it depends what type of skin you used in the first place. the reason they use calfskin for parchment/vellum is that it's much more supple than adult cowskin, which becomes leather instead; goats and sheep are also common for parchment. since rawhide is a byproduct of the leather industry i would expect it's made of the much tougher materials to start with. also, since it's a byproduct, it may be that they've split off the layers that would be used for parchment etc anyway? not sure, this is where not knowing a huge amount about rawhide lets me down

secondly there's the processing and specifically there's a lot of stretching: you stretch parchment over a frame to make it thinner (and larger) and this probably also makes it a lot more pliant, and then you scrape it more at that point, having already got rid of a lot of the gunk before that stage. my cursory googling suggests that rawhide doesn't involve a lot of stretching, so this might also be part of the process of making it bendier, along with how much they scrape off and what they soak the skin in to loosen hair etc in the first place!