U of S | Mailing List Archive | alt-photo-process-l | Re: Seeking Information on 2 problems with Gum process

Re: Seeking Information on 2 problems with Gum process

The secret to using cyanotype as an underlayer without its getting too dark is to properly develop a curve for it. It is a very short stop, contrasty process and either you underexpose it and get no highlights or you expose it correctly and get blocked up shadows. It has to have a curve that flattens the negative considerably. I personally use the PDN system developed by Mark Nelson but there are also other methods to do this I'm sure....perhaps Dan Burkholder has a cyano curve on his website.

However, another option I have been working with is to print the cyanotype layer weakly JUST for lightbox registration purposes, and then using thalo blue as my last layer to print in the majority of the blue in the image. It gives it a more "gummy" look that way and more punch. I have also found that more gum layers give that nice sheen to the image that I love.

----- Original Message ----- From: "cadunn" <cadunn@vt2000.com>
To: <alt-photo-process-l@usask.ca>
Sent: Wednesday, April 30, 2008 4:50 AM
Subject: Re: Seeking Information on 2 problems with Gum process

Henry wrote:
but I found it much better to dilute
the coating solution with anything up to six or seven times its own volume
with water. You can hardly see it as you coat it, but the blue is there OK
and you can give it full exposure. Dilute solutions seem to need rather less
exposure than full-strength ones.

lol, Henry -- your msg. came JUST after I had coated the paper and was planning on a much reduced exposure time, which is all at this point in my learning curve that I knew to do --

So, next iteration of cyanotype stage variation belongs to you!