Yesterday the ink was acting funny and I needed to figure out what was going on. I posted about it here.
Today, I had some precious spare time and inspired by an e-mail I received from Randy Asplund (click on his name to visit his website,) I decided to do some quick experimenting based on his suggestions.
I added alum to the bottle. Alum is acidic so it is on the lower end of the pH scale. Some quick checking on the internet showed a pH of about 3.4 giver or take. Adding alum caused the ink to go on dark purple and then go to black in a matter of seconds.
That made things worse so then I added baking soda a known base. This ink uses vinegar. Baking soda and vinegar cause a fun reaction of giving off gas and foaming up and if in a contained area with a nozzle at the tip, say like an ink bottle, that foam comes shooting out the nozzle area. Fortunately it was a small amount.
When the reaction was completed I tested the ink with the dedicated metal 0.75 brausse metal dip pen and a poorly cut freshly made quill pen. I wrote on the same support as before, that is to say, the same sheet of paper so there would be no differences and I wrote side by side to make comparing them easier.
The results were definitive.
So somehow the metal brausse nib is causing the ink to become more acidic. So now we know. At least with this recipe for Brazilwood Ink, the pen you use makes a significant difference.