Re: glyoxal yellowing

From: Kees Brandenburg ^lt;>
Date: 02/03/05-01:02:50 PM Z
Message-id: <1320915.1107457370448.JavaMail.swiki@G3.local>

>Kees, the Maco hardener---very interesting! Is the percentage of
>glut in it really 2.5-5%? If so, then 50 ml of this is a lot more
>than my 6 ml. per liter of gelatin.

Yes, it is a lot more then your 6 ml. In fact I reduced it a lot later and hardened also with 6 ml. Indeed I am sizing and hardening in two steps. I do tray sizing in big batches and continue sizing sometimes the next day. When mixing the hardening agent with the gelatin it doesn't keep.

I posted about the Maco geladur before on this list.


The percentages are from the Maco Geladur safety sheet(somewhere on, the english version is missing - but I have a pdf somewhere).

For gum printing the gelatin has to be hard enough to resist the abrasion from the coating,soaking, streching and drying. But there is always a difference between coating a first layer over the hardenend gelatin and the next layers of gum. The first layer is allway somewhat unwilling to smooth. Second and folowing coatings are much easier to egalise. I have the impression that too hard gelatin is moer difficult to coat. When I tried coating my first glut paper (yes the 50 ml one - fabriano uno - a first try unfortunately - not so clever when researching a new approach)it was very hard to coat. Overhardened?

Received on Thu Feb 3 13:03:05 2005

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