I'm getting ready to try vinegaroon for the first time on a project, so I made up a batch and tested it on a scrap of leather, brushing it on some of the scrap, waiting a day, and then soaking the leather in baking soda dissolved in water for a few (less than 3) minutes. I only vinegarooned the very end of the scrap, but I dunked the whole scrap into the baking soda solution. The vinegarooned portion came out perfect, and all vinegar smell was gone. However, the un-vinegarooned end of the leather seems to have been significantly darkened by the baking soda solution; it's now a medium to dark brown. My baking soda solution was about 2 tbsp dissolved in about 8-10 ounces of water.
So, I have two questions:
1. Can a baking soda solution be used as a cheap dark brown dye, similar to the way vinegaroon is used for black?
2. I'm assuming the darkening of the leather is a result of the baking soda burning it, which presumably could lead to problems similar to not neutralizing vinegaroon. So, is it necessary to use a specific strength formulation of baking soda solution to prevent a swing from one end of the ph scale to the other, rather than ending up in the middle?