old school comic artists used gouache for the fact that it was easy to photo reproduce (no reflection) and easy to correct. The comic artist Glen Fabrey still uses gouache. digital artists miss out on a lot of nuance unless they really know what they are doing.

I’ve taken to painting with charcoal lately.

I draw with vine charcoal, smudge and adjust, then wash it on canvas with a brush dipped in water, it makes a nice watercolour style effect. I suppose it’s more like gouache after reading this.

I started experimenting with compressed charcoal crayons too. I dip them in water then rub directly into canvas. It gives a very strong black which is perfect for accents and dark surfaces.

Might be obvious, but their videos and tutorial articles are way over the top for a little importer / retailer. Fair warning, they'll either have you grabbing your current supplies inspired for a project, or shopping for stuff.