I mix up my own washes. There are plenty of recipes online, but video related has been the one I’ve used as a foundation for a while.
I somewhat follow the recipe in the description, though for my “nuln” I use 18 drops of black ink, and 8 of burnt umber. For the brown wash I use 16 drops of burnt umber, 6 of sienna, and 5 of black. I think it looks a bit better, but the great part with DIY is how much it can be changed up.
I keep steel mixing balls in the bottles and always give them a vigorous shake when everything is added.
It’s just figuring out the colors.
I don’t use this guy’s recipes, but he does have a sepia color, as an example of what’s possible.
Thanks! I’ll have to try it when I run out.