Well, it would seem that making black dye is still broken - or at least so RNG'd as to make it virtually impossible to make high ql dye.
I have 79 natural substances skill and 45+ alchemy skill, but:
Using over 90 x 81ql acorns, tannin resulting over 70ql was less than 1 in 10
Using over 75 x 87ql iron lumps and the 50-70+ql tannin, the black dye results were: 15kg of 73ql black dye and 17kg of 53ql black dye.
73ql black dye is R23, G23, B23 = dark grey not black
53ql black dye is R43, G43, B43 = grey and not black
This is RNG at its worst and would suggest to the new Dev team: PLEASE to look into this - you have done such a great job on other RNG actions like beverage making - please do do look into this. Pleeeeeaaase.