Re: Carmen's carbon
Sandy King (sanking@hubcap.clemson.edu)
Mon, 28 Oct 1996 23:04:50 -0400
>> dichromate should be around 3%. yours is way too high.
>>
>> recommended:
>>
>> 70 ml water
>> 7 g gelatin (1 knox package)
>> 3 g sugar (one of those individual packages)
>> 8 g Rowney jet black guoache
>> 6 g ammonium Dichromate.
>> photoflow a few drops.
>
>
There sure were many problems that surfaced in the description of Carmen's
carbon. Lord knows the effect of force drying the wet tissue with hair
blower (was this hot air?). I personally believe that the disadvantages of
incorporating dichromate into the coating solution outweigh the advantages,
and are particulary problematic for begineers. And when dealing with
quantities of coating solution as small as 70ml the question of accurate
measurement is critical. In fact, Carmen's account in terms of measurments
is so nebulous as to obviate any intelligent response as to the problem. I
suggest that she make up some tissue without dichromate and sensitize after
it has dried, making up a bottle of 2/3% potassium dichromate sensitizer
(that is, 20-30 grams per 1000ml of water).
Sandy