Re: sensitizing for carbon

Albert Strauss (a.strauss@worldnet.att.net)
Wed, 27 Nov 1996 00:22:09 +0000

At 10:14 PM 11/26/96 +0000, Klaus wrote:

>It is a good idea to prepare the tissue in the evening if you want to use
it the
>next morning. But without some precautions it will gain too much speed and will
>fog. To avoid fogging, don't use the brayer method for sensitizing [I sometimes
>use a spirit sensitizer and apply it with a foam brayer, if I don't want to
wait
>hours for the tissue to dry] , but soke in a ca. 2% sol. of pot or amm
>dichromate to which you have added strong ammonia until the sensitizer's color
>just turned from orange to yellow.

When do you soak the tissue in the 2% solution? What does the ammonia do ?

I have been sensitizing my home-made tissue by brushing on ca. 3% pot.
dichromate
(half water/half acetone) with a foam brush about 1 hour before use. I do
this in
dim light and then let dry in complete darkness. I have never had a fog or speed
problem.

Cheers

Al