From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 04/16/00-03:50:43 PM Z
At 02:10 PM 04/16/2000 -0700, you wrote:
>Allow me to repeat the following without typos and poor grammer.
>
>This new paper coming out from Bergge sounds like a good deal, if it
>replicates the old Nievera; because that older paper sounds like good stuff.
>The idea of its texture is appealing.
>
>The tonal values of green in the black color may be due to the photographic
>printer using cold developers. When paper developer is used at a
>temperature below the recommended or colder than normal, it tends to make
>the black color with a green, metal tint appear on the shadow levels of the
>photographic print.
>
>
Its interesting that the catalogue descriptions of some of the gas-light
papers from the 'twenties and 'thirties describe the image as being a green
color. I don't know if this was due to the image structure or to something
chemical in the emulsion. Gas-light papers must be very slow, much slower
than ordinary contact printing papers were. Their spectral sensitivity must
also have been pretty much confined to the far blue and near UV region.
Both gas-mantle and electric incandescent lights are pretty weak in the blue.
AFAIK, the first gas-light paper was the original Velox, invented by
Baekeland. Koak acquired the rights at some point (they were buying up
everybody they could) but the Velox of later years was not a gas-light
paper but rather a fairly fast contact paper with a blue-black image tone.
I found a reference to a gas light paper in a late 1930's book last
night. The brand was Tuma-Gas. I think that was a San Francisco company.
All their papers were sold under the Tuma-Gas name but they made a variety
of types. The description of one is a gas-light paper with green image
color.
---- Richard Knoppow Los Angeles,Ca. dickburk@ix.netcom.com
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