ochre for tanning hides

[idris]

I have read in several places that ochre/ocher used to be used to preserve hides.
Anyone know anything about that?

[idris]

Having read, in the Permaculture Book of Ferment & Human Nutrition [Tagari Publications}, that red ochre is used to leach tannin from acorns and other nuts, and then trying it out. I went 'Aha!'. Tannin is also usd to tan hides, and this brown liquid could be used to do just that. [I mixed the two with water and boiled it a little] The iron in the red ochre unites with the tannic acid, and so holds it. [ferrous tannate, if I remember aright] When I have found out or figured out more, watch this space.
It is a ferric tannate: very complex method. *A useful sidelight is that tannic acid in water is a useful antidote to strychnine and most fungal poisons [toadstools]; take a little , diluted in water. also, one could write much on the topic of clays and earths used in food preparation.
http://www.henriettesherbal.com/eclectic/kings/acidum-tann.htm
I guess that ochre was put onto hides which were then hung air dried, which is a way of curing them.