My first test with logwood ink and various modifiers turned out really well!
From left to right they are -
logwood, logwood + alum, logwood + soda ash, logwood + iron water, logwood + citrus juice.
Of all the inks I've made I think this one has the most variety of color. I love the midnight blue shade and was incredibly surprised with the yellow!
If you'd like to play around with these colors I've made a small kit featuring the ink and modifiers, all diluted, bottled, and ready to use. You can find it here in my etsy store.