Here are two medieval leather dye recipies, they can be found in;

Middelnederlandse verfrecepten

Published by W. L. Braekman (Scripta 18)

Book I

Ms. 517 From the Wellcome Historical Medical Library in London.

Manuscript from the late 15th century. The manuscript contains many texts varing in language (latin and middle dutch) and a divers of subjects (technical, medical, recepies, etc.).

I.63 Om leder zwart te maken recipe .ii. maten zwarten, .2. Loet vitrioels, .4. loet galnoten, dit pulu(er)izeert ende menget mitten zwarten, ende .i Loet olye, dit laet te samen sieden, so is die verwe bereyt, ende dan striicse opt leder mit enen hasen voet .3. Of .4. weruen, so lange tot dattet zwart ghenoech is.

Recipy .ii. measures black, .2. loet vitriol, .4. loet galnuts, this is pulverized end mixed with blackened, and .i. loet oil, boil this togheter, this way the dye is prepared, and rub it unto the leather with a hare's foot .3. or .4. times, until it is black enough.

Loet, loot, loodt = weight measure equal to 15 gram.

Book II

Texts from Tbouck van Wondre

Printed in 1513 by Thomas van der Noot

The book contains recipies for working on steel and iron, as well as dyeing. The book was very popular, shown by at least two reprint (1533 and 1551) and translated into english in 1583 (Leonard Mascall, " A profitable booke declaring dyuers appooued remedies to take out spottes and staines..."

II. 59 Noch om root leer. Om root leer te verwen, neemt een loot breselien ende eenen pot nats, also laet dat derdendeel versieden, maer wascht v leer eerst in aluyn water oft in ander water, daer en es so veel verlancx niet ane, latet dan drooghen, dan steket daer inne ende latet rotten twe daghen ende twee nachten nachten met natten spanen ende hanghet dat leer daer ouer ontloken.

Item wildi sangwijn hebben, soe neemt wijnrancken asschen ende maecter looghe af, ende met dien looghen so siedet dijn breseliehout ende rootet als dander.

To dye leather red, take a loot breselien* and one pot water, boil it until two thirds, but wash the leather first in alum water or in other water, use a lot to prevent loss of time, let it dry, put it in and ;et it red two days asnd two nights with wet spanen and hang the leather folded open.

Item if you wish to have bloodred, so take ash of grapevines and make a base (hydroxide) and with this base boil the bresilwood and red it as the other.

*breselien, brasiletum = fernambukhout, Caesalpinia echinata lam.