Re: Chrome Alum Gelatin hardener

I don't know why gloxal does not yellow for everybody, but it sure
yellowed for me and I won't use it anymore.

In a thread quite a long time ago someone mentioned that the shell
life of glyoxal is limited and if true this might have something to
with the yellowing. Or, perhaps it is something in the water?

In any event chrome alum works perfectly well in my application,
(hardening final support papers for the carbon transfer process). It
may well be that chrome alum hardened crosslinks are much weaker than
those made by aldehyde hardeners, but in my work sufficient hardening
for the purpose is quite satisfactory.

Sandy

>Clay
>I have been using your method of gelatine/glyoxal siezing and have not
>noticed any yellowing. Hey, I even use your paper. I have some siezed
>papers sitting on my desk for weeks now. Some with Pd prints, some just
>plain paper. They are fine. I wonder if there might be something in your
>Pd processing that leaves a residue that reacts with your gelatine/glyoxal
>mix to make it yellow.
>Marek
>
>> But you don't say whether you rinse the hardened paper before it dries.
>> That is, harden for 5 (or however many minutes) and then rinse in fresh
>> water before drying. I'm trying to figure out why it doesn't yellow for
>> everybody.... and that might possibly be the variable. And since you say
>> that having "run it through wet steps at least once" prevents it.... well,
>> it's a thought.
>>
>> J.
>>
>> MIME-Version: 1.0
>> Content-Type: text/plain; charset=ISO-8859-1
>> Content-Transfer-Encoding: 8bit
>> User-Agent: Internet Messaging Program (IMP) 3.2.1
>> X-Originating-IP: 24.167.11.151
>>
>> Judy:
>>
>> No I haven't been rinsing the paper, because I have been using the one
>> step
>> hardener-in-the-gelatin sizing routine. I am brush or rod sizing the pd
>> print,
>> and then letting it dry on a screen.
>>
>> So it may well be a procedural difference that is introducing the effect.
>> One
>> thing to keep in mind is that I notice this yellowing more because I
>> typically
>> do not size all the way to the edge of the paper. So could it be that
>> maybe it
>> isn't being noticed in some instances because the entire paper is sized
>> and
>> there is no unadulterated paper with which to allow a comparison? ( as
>> would
>> be true in the case of tray sizing)
>>
>> On a second note, I googled glutaraldehyde, and the first two pages were
>> health warnings and MSDS information about possible side effects from
>> exposure
>> to this chemical. These effects sounded awfully similar to those of
>> formaldehyde. Is there any other inherent advantage other than the ones
>> mentioned. (I guess this part is directed at Ryuji)
>>
>>
>>
>> Clay
>>
>>
>> But you don't say whether you rinse the hardened paper before it dries.
>> That is, harden for 5 (or however many minutes) and then rinse in fresh
>> water before drying. I'm trying to figure out why it doesn't yellow for
>> everybody.... and that might possibly be the variable. And since you say
>> that having "run it through wet steps at least once" prevents it.... well,
>> it's a thought.
>>
>> J.
>>
>>
>>
Received on Tue Feb 10 11:04:40 2004