I just read a fanfic with atrocious depiction of hide use, so here, have a Tanner's Guide to Writing Tanning
The skin of the animal that hasn't been processed at all is called a hide.
You remove the hide from the animal by skinning it, typically in conjunction with dressing it ( = cutting the meat bits off according to muscle groups).
Once you have the hide off, you decide whether to start working on it right away or preserve it for when you have time for it. Keep in mind that by the time you're skinning the animal, you have probably been stalking the animal for hours already.
If you choose to preserve the hide, you usually do it one of three ways:
1. Salting 2. Drying or 3. Freezing
For salting, you spread the hide out hair down, flesh side up so there are no folds. You spread salt over the flesh side and leave it somewhere dry for a couple of days. After that, you change the salt for fresh salt. The first salt draws out the blood, the second salt loosens the membranes and keeps any flesh from rotting.
For drying, you usually use a frame of some kind of wood. You make holes in the edges of the hide and fasten it to the frame with string through those holes. By spreading it like this you can tighten it a lot so the largest amount of the flesh side possible it exposed to air, and it will dry faster.
For freezing (usually done in cold climates), you fasten the spread hide to a wall with the hair against the wall. Then you hammer spikes into the edges of the hide and leave it until freeze-dried. Yes, this makes your walls look kinda gory.
Once you want to start working on the hide, the first thing you need to decide is whether you want to make fur or leather.
If you're making fur, you start by scraping any flesh and membranes off of the flesh side.
You then wash the hide, doing your best to get any dirt / blood / salt out of it.
You then tan the hide. If you're writing historical fiction, most of the time this will be done either by bark tanning or oil / brain tanning. (Arctic areas have their own techniques which mainly involve working the fat of the animal itself into the hide. These only work in cold areas.)
For bark tanning, you need the bark of trees (the older, the better). You boil the bark, removed the bark when boiled and just use the water, which now contains the tannins and the dye. This is called the liqour. For tanning a hide with the fur, you either submerge the hide in the bark liqour (which will dye white fur) or you stretch the hide in a frame and brush the liqour onto it.
For oil / brain tanning, you make a tanning solution of oils. Traditionally this is done with water and the brain of the animal, which is heated up and then massaged into the flesh side of the hide. You can, however, also use a combination of eggs and vegetable oil, which doesn't need to be heated.
If you're doing leather, you need to de-hair the hide. This can be done either with lime, ash, or under running water.
Once the hide has been scraped and de-haired, you then decide what kind of leather you make. If the top layer of the skin (the grain) looks good, you can make your average leather. If there are lots of scars or you've nicked the grain, you can remove it and instead make either suede by bark tanning it, or chamois or buckskin (which is essentially smoked chamois) by oil tanning it.
You can also make rawhide by simply stretching a scraped, de-haired hide and letting it dry. You probably know rawhide from dog toys, but it can also be used to make drum skins, lanterns and primitive windows, since it lets the light through.
If you then sand the grain off the rawhide, you can make parchment. Parchment does not fold the way paper does - but it does bend. Hence it commonly being stored in rolls.
misc stuff a tanner would definitely know:
