Re: dichromate stain and chemistry question
On Jan 7, 2007, at 7:29 AM, Christina Z. Anderson wrote:
This doesn't look like Greek to me, but it's incomprehensible just the same. There's no reference given, but from the sound of it I would guess it dates back to the early days long before chemistry advanced to the understanding of the photochemical process that we know today to explain the process. Just the beginning statement, "Light acts the same as heat" is incomprehensible in the light of this knowledge. So I'm not sure how useful this information could be to us, but since no chemists here have responded, I've forwarded it to my physical chemist colleague for comment, and will report back his comments when he replies, whatever they are.
The record will show that I was skeptical in the beginning because you were talking specifically about YELLOW dichromate stain, which is unreduced dichromate or chromate, which of course would turn brown when exposed to the sun, as the light would reduce it in the presence of the organic materials in the paper or the size. When I said that, you corrected yourself and said actually you didn't mean YELLOW stain, you meant brown stain. So I said okay, I've got to try that, and I did and found that it worked, and reported back to the group that sun does indeed work to fade the stain, although I was only able to fade the stain, not to eliminate it. There was no scoffing involved, and I'm really rather tired of an honest disagreement on issues being characterized as "scoffing," as well as things being misrepresented and taken out of context, in that you only referred to my initial skepticism in characterizing my position, rather than taking the discussion as a whole, in which I did do the test and agree that sun fades the stain.