Expert: Henry Boyter - 11/15/2006

Question
Hello, I am a video artist, and I am trying to create a certain effect, for an art project: I need a writing material (ink, paint) that will dissolve when put in liquid. The idea is to write text on a page, then insert the page into a container with (transparent) liquid, or pour the liquid on the paper, and then the ink should come off completely and dissolve into the liquid, without need to rub it off the page. I have tried with several combinations such as water-based color in water, and oil-based color in liquid thinner, and nothing has had satisfactory results so far. My search on the web has only come up with disappearing ink, which I believe won't do the trick, and isn't easy to obtain.
I am using different kinds of non-absorbing paper to write on.
Thanks in advance for any insights you might have.

Gil

Answer
Two thoughts.  Not clear to me if you want the color to appear or disappear in the water.

1. Try red cabbage, beet or prune juice.  You may need to make the water slightly acid (vinegar) or basic (baking powder) before you add to the paper or the water in the jsr slightly acidic or basic.  This is just a home version of #2 but you will need to do some experimenting and find the correct paper.

2. You could try an acid indicator, which is just a dye.  You may need to apply it in basic solution and then have the water acid.  If it didn't all come off, it should turn colorless.  This is how invisible ink works and phenolphtalein is easy to get.  It is not to be used on anything the public or children would be exposed to.  It isn't highly dangerous, but it is a chemical.  See

http://en.wikipedia.org/wiki/Phenolphthalein