I bought this at my local fine art supply for drawing, and I have to say it's more a drawing ink than a calligraphy ink due to the thin viscosity of the ink itself. My local art supply sells these for $6.95 per bottle. I love drawing with warm browns, so I purchased Indian red which is like a brown-red iron oxide color. One thing I noticed is that while it says that it's not waterproof, when left to dry and sit for an hour or so, this particular color is highly water resistant; at least the bottle and color I purchased. I especially like that it's a pigment and not a dye based ink which is better for archival art purposes. I couldn't get it to rub off which made me happy as it's hard to find a warm red-brown earth tone ink that is pigment based and still able to be used in a fountain pen.  It's similar to Diamine ancient copper though it's not quite as pretty or as coppery-brown as the translucent Ancient Copper dye ink is. This isn't completely waterproof, a very light wash of the color moves around when water is brushed over it, but this particular color has staying power. I tested this with a Fabriano dot pad bullet journal, which doesn't absorb ink or water rapidly, so I still need to test this on hot pressed cotton watercolor paper, drawing paper and Stonehenge cotton drawing paper.
I bought this at my local fine art supply for drawing, and I have to say it's more a drawing ink than a calligraphy ink due to the thin viscosity of the ink itself. My local art supply sells these for $6. 95 per bottle. I love drawing with warm browns, so I purchased Indian red which is like a brown-red iron oxide color. One thing I noticed is that while it says that it's not waterproof, when left to dry and sit for an hour or so, this particular color is highly water resistant; at least the bottle and color I purchased. I especially like that it's a pigment and not a dye based ink which is better for archival art purposes. I couldn't get it to rub off which made me happy as it's hard to find a warm red-brown earth tone ink that is pigment based and still able to be used in a fountain pen. It's similar to Diamine ancient copper though it's not quite as pretty or as coppery-brown as the translucent Ancient Copper dye ink is. This isn't completely waterproof, a very light wash of the color moves around when water is brushed over it, but this particular color has staying power. I tested this with a Fabriano dot pad bullet journal, which doesn't absorb ink or water rapidly, so I still need to test this on hot pressed cotton watercolor paper, drawing paper and Stonehenge cotton drawing paper.