From: Katharine Thayer (kthayer@pacifier.com)
Date: 07/14/03-10:31:10 AM Z
Katharine Thayer wrote:
>
> Well, it's been two hours, and I'm not seeing a bleaching effect as yet
> on either dichromate.
Now it's another hour, (3 hours total) and I am noticing a visible
difference between the stain exposed to sun and the stain covered from
the sun, although I would call it a difference in color rather than in
density. The covered stain is a bit brighter and more yellow-brown,
whereas the uncovered stain is more a dull brown. This is equally true
for both dichromates. I suspect this has to do with very small amounts
of hexavalent chromium left in the stain after development, which have
converted to trivalent chromium with further exposure to light.
(Where else but here could you get a play-by-play account of a
dichromate fade test, I ask you?)
kt
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