Reduction of triphenylmethane dyes in ink

Right now I'm trying to explain why the ink from an ink pen turns colourless in water.


I know that the pH is responsible as it breaks apart the conjugated system of double bonds. I'm just not sure on which part, to $\ce{OH-}$ comes into play (example: [Water blue](https://en.wikipedia.org/wiki/Water_blue)).


My suggestion would be that $\ce{OH-}$ can be reversible added to double bond in the center forming two phenyl rings and one ring with 2 double bonds (which will rearrange into a phenyl ring with the double bond from the following amide-group) with a $\ce{C-OH}$ in between.


Under acetic conditions, the $\ce{OH-}$ is eliminated.


Is that correct and does anyone know a mechanism, explanation etc. for that reaction somewhere on the Internet?


