[alt-photo] Re: Multi coat Gum -3rd+ coats tends to wash off

[Loris Medici]

Maybe you're coating very thick (try to coat thinner - the thinner is the
coating the better/easier the process is) and/or maybe you should thin
(dilute) your emulsion a little bit. What is the strength of your gum
solution? 1:2 to 1:2.5/1:3 gum/water (w/w) seems to be the most used
dilutions, given they're further diluted it 1:1 with dichromate.

BTW, in the last workshop I had a student who have done up to 9 (nine!)
layers (Don't ask me why because I don't know. The result was beautiful
though...) on PVAc glue sized Fabriano Artistico HP w/o flaking.

Regards,
Loris.


-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org On Behalf Of
Paul Viapiano
Sent: Wednesday, February 24, 2010 1:05 AM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: Multi coat Gum -3rd+ coats tends to wash off

Peter,

I experience this on my 3rd coat with this same paper, but usually with a
layer of PVA size after the 2nd coat.

Look into exposing the 3rd coat longer, or shortening the development...

Paul



----- Original Message -----
From: <pfriedrichsen at sympatico.ca>
To: "The alternative photographic processes mailing list" 
<alt-photo-process-list at lists.altphotolist.org>
Sent: Tuesday, February 23, 2010 1:54 PM
Subject: [alt-photo] Re: Multi coat Gum -3rd+ coats tends to wash off


> John,
>
> The paper is Fabriano Artistico Hot Pressed Extra white. I did not use any

> additional sizing. I believe that the manufacturer is internally sizing it

> with AKD, which does a pretty good job .AFAIK some gum printers add their 
> own sizing to this paper while others do not because it is very "gum 
> compatible" right out of the box.
>
> Regards,
>
> Peter Friedrichsen
>
>
> At 02:48 PM 02/23/2010, you wrote:
>>Hi Peter,
>>
>>What paper, including finish, are you using? What are you using as a size?
>>
>>J
>>
>>-----Original Message-----
>>From: alt-photo-process-list-bounces at lists.altphotolist.org
>>[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf 
>>Of
>>pfriedrichsen at sympatico.ca
>>Sent: 23 February 2010 19:11
>>To: alt-photo-process-list at lists.altphotolist.org
>>Subject: [alt-photo] Multi coat Gum -3rd+ coats tends to wash off
>>
>>Has anyone experienced the following problem?
>>
>>When doing three or more separate coats of gum, I find that the third (and
>>all subsequent)coats have a tendency to wash off. The wash off occurs only
>>where the previous undercoats remain. In areas where the paper remains
>>uncoated (highlights), the top coat will anchor. I am guessing that the
>>fibers, voids, etc are being filled in and the top coat has little left to
>>anchor to.
>>
>>There must be something that I do not have right but am unsure of what 
>>that
>>might be. When I tested the individual coats on clean paper, they adhere
>>well and do not flake or wash off and produce an image with good scale.
>>
>>Any ideas?
>>
>>Peter Friedrichsen