Re: "new" color printing process Was: Cyanotype
Luis Nadeau (nadeaul@nbnet.nb.ca)
Sun, 15 Mar 1998 17:16:26 -0400
At 10:50 PM -0400 98/03/14, Luis Nadeau wrote:
>At 11:17 PM -0700 98/03/13, Richard Sullivan wrote:
>>I didn't have any time to jump in on the cyanotype discussion during the
>>week. In my favorite phrase of late -- "I've been busy killing alligators
>>instead of draining the swamp."
>>
>>I do think Mike Wares' Cyanotype is superior to the conventional version.
>
>Speaking of cyanotypes, I just came across an article in an old journal
>(1915) reviewing a new process patented by John Lewisohn, of New York.
>Briefly:
>
>A negative of a colored object is made on an orthochromatic film with a
>yellow filter. From this neg an ordinary blueprint is made. This blueprint
>is then colored either wholly or in part with dye or paint, but preferably
>by applying eosin for the magenta and aurantia for the yellow, or a mixture
>of the two to modify the blue to form any of the spectrum colors. Should it
>be desired to make all or any material portion of the print either red or
>yellow, or any other color in which blue is not used the blue of the
>blueprint is either wholly or partially dissolved by a weak solution of
>nitrate of silver, which will fix the colors, and at the same time will
>gradually bleach the blue. Further, the blue print may be washed with this
>solution if it is desired to merely weaken the blue color of the object,
>after the eosin or aurantia has been applied.
>
>Should it be desired to restore the blue locally or entirely, or to darken
>the blue color, the blueprint is respectively touched up or bathed with a
>solution of ferric chloride, and this may be applied in stronger solution
>or in succession until that part of the object is practically black.
I forgot to mention that the above coal tar dyes would be fugitive... One
would be better using high quality watercolors
Luis Nadeau
NADEAUL@NBNET.NB.CA
Fredericton, New Brunswick, Canada
http://www3.nbnet.nb.ca/nadeaul/