Re: APIS, hydroquinone hardening

Thankyou for your comments Ryuji. I look forward to seeing how that works
out in real printing.

jack

> From: Ryuji Suzuki <rs@silvergrain.org>
> Reply-To: alt-photo-process-l@skyway.usask.ca
> Date: Wed, 13 Jul 2005 16:26:09 -0400 (EDT)
> To: alt-photo-process-l@skyway.usask.ca
> Subject: Re: APIS, hydroquinone hardening
>
> From: Jack Brubaker <jack@jackbrubaker.com>
> Subject: Re: APIS, hydroquinone hardening
> Date: Wed, 13 Jul 2005 14:58:35 -0500
>
>> As a fellow gum printer who doesn't feel I have found the Holy Grail of
>> sizing options I to was excited about this idea. Paul found that a gelatin
>> coating that contained a small amount of hydroquinone could be hardened by
>> the addition of a small amount of dichromate.
>
> This can work, but the net effect should be similar to addition of
> chrome alum. Presence of oxidized hydroquinone in absence of sulfite
> may also help to form a different kind of crosslinking. But personally
> I don't see why one might want to use more than one step of work for
> the hardening process when one is enough. Addition of a very small
> amount of glutaraldehyde immediately before coating works as good as
> anything else I tried and it is by far the easiest hardening process I
> know of.
>
>> The dichromate could be either brushed on and then washed off once
>> the reaction had occurred or perhaps the usual gum coating could be
>> brushed on and the sizing under it would be "set" by the dichromate
>> in that first layer of gum.
>
> If you do the latter, I would expect the "fog" level to rise.
Received on Wed Jul 13 17:14:12 2005