U of S | Mailing List Archive | alt-photo-process-l | RE: A few gum things

RE: A few gum things

HI Diana,

When you said it didn't work, how did it not work? Did it harden not enough that you still got pigment stain? Or did it harden too much that the image would float off? Or something else?
 
Also, what paper were you using? Was it somewhat sized? Totally unsized as in unsized rice paper or some printmaking paper? Or?
 
 
Dave
 

From: Diana Bloomfield [mailto:dhbloomfield@bellsouth.net]
Sent: Monday, April 07, 2008 10:19 AM
To: alt-photo-process-l@usask.ca
Subject: Re: A few gum things

Hi Marek,

Thanks.  He shows 2 options in his book.  The first option is just as you have stated, but not using gelatin and dichromate-- rather, using gum and dichromate.  He suggests mixing up a gum dichromate solution of 5ml of dichromate (either potassium or ammonium), 10 ml of gum arabic, and 10 ml of water and exposing it to UV for 5 minutes.   The other is coating with equal proportions of a saturated dichromate and gum- coat it, let it dry, and expose to UV for 1-3 minutes.  This is the version I tried-- then washed it.  The other place wheere I saw this mentioned was in Sarah Van Keuren's workbook, but she suggests spreading the dichromate on the paper first, and then spreading the gum as a separate layer on top of that.  I'm not sure if it makes a difference (rather than initially mixing them together and then spreading), but on the off-chance it did make a difference, I tried that, too.  That didn't work either.  I'm guessing the difference is that you're using gelatin and not gum?    If you could email me the details that you use, that would be great.  Thanks, Marek.

Diana
On Apr 7, 2008, at 9:49 AM, Marek Matusz wrote:

Diana
I use gelatin / dichromate to size papers. Works quite well for me in a tri colour gum. I am not sure what is the procedure that James has, so I can not comment on it. You have to remember that dichromates are not the crosslinking agent. They have to be converted Cr (VI) from the dichromate to  Cr (III), by either dark reaction, which is slow, or UV light. I coat with gelatin / dichromate , let dry and expose to sunlight for 15-30 minutes to harden the gelatin. I can email details if you want to try. 
Marek

> Date: Mon, 7 Apr 2008 00:27:47 -0400
> From: dhbloomfield@bellsouth.net
> Subject: Re: A few gum things
> To: alt-photo-process-l@usask.ca
> 
> Oh, I would like to also add that I tried that sizing suggestion in 
> James' book (and I saw it mentioned somewhere else, too) where you 
> size with gum and dichromate-- I tried that twice and couldn't get it 
> to work. Has anybody ever actually tried that, and does it work?
> 


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