Colors of Dichromate Stain (was:Re: Sodium Bisulfite

Katharine Thayer wrote: (Wednesday)

> Hi Giovanni,
> Just out of curiosity I did this comparison myself. I was going to show
> the results, but my scanner is scanning too red and in trying to fix it
> I'm not getting the results the right color and tone to accurately
> reflect the originals, especially to show a very very faint blue-grey
> tone accurately. Since I don't have any more time to spend on it, I'll
> just have to describe the experiment and results:

Hi Giovanni, Alberto and all,
I ran another comparison, adding more conditions, and this time I used a
different scanning program that doesn't add the red cast that my
SilverFast has been doing, and have got what looks to me a fairly good
approximation of the pale colors, although the blue still doesn't show
very well.

http://www.pacifier.com/~kthayer/html/gumcolors.html

Contrary to my expectation, I did find, as Alberto suggested, that
leaving the stain in water 12 hours longer did fade it, although the
water didn't take on even the palest of yellow tint, and I wouldn't say
that the water actually "clears" the stain, it just fades it. I also
tried salt water, for reasons related to a private discussion, and found
that it worked much as the clear water, fading the stain but not
altering it. Both the sodium sulfite and the bisulfite removed the brown
stain and turned the gum a bluish-grey color, although the sulfite took
longer to get the same effect.

These are the colors of dichromate stain that occur in my gum universe.
It's interesting to consider that there are other gum universes in which
the colors are different.
Katharine Thayer
Received on Sun Oct 17 10:09:07 2004