Re: glyoxal yellowing

Kees,
Great results and diligence! (you still deserve it even with a typo.)

Is there a chance you could obtain a sheet of Fabriano Artistico EW paper
and test your process on that, too? I did the afterbath and rinse process
with the lower dilution of glyoxal (15ml) and still got yellowing.

If you do not have access to that paper and aren't too far away, I would
gladly send you a sheet.

Don, I always get grittiness with glyoxal and never use baking soda (and the
next time you come I'm going to accidentally sprinkle baking soda on your
morning strawberries).

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. BUT, if this is truly a 2.5-5% glut, then a consumer
would be able to buy glut over the counter in small quantities and that is a
great thing! Also, any dire warnings on the back of the bottle? Maybe I'll
just have to buy some...this would totally solve my problem of how to harden
gum in a classroom situation.
Chris

From: "Kees Brandenburg" <ctb@zeelandnet.nl>
> sample 1: M 0.06, C 0.06, Y 0.07 (unsized, unhardened)
> sample 2: M 0.06, C 0.06, Y 0.07 (sized, unhardened)
> sample 3: M 0.06, C 0.06, Y 0.07 (sized, soaked for 3 minutes in 1 liter
> water with 15 ml formalin(37%), dried )
> sample 4: M 0.06, C 0.06, Y 0.08 (sized, soaked for 3 minutes in 1 liter
> water with 15 ml glyoxal (40%), rinsed for 5 minutes in running water,
> dried )
> sample 5: M 0.06, C 0.06, Y 0.12 (sized, soaked for 3 minutes in 1 liter
> water with 15 ml glyoxal (40%), dried )
> sample 6: M 0.06, C 0.06, Y 0.07 (sized, soaked for 3 minutes in 1 liter
> water with 50 ml Maco Geladur (this is a 2.5 - 5% glutaraldehyde
> solution), dried )
> Conclusion stays unchanged: unrinsed glyoxal hardening yellows paper,
> rinsed glyoxal hardening gives no visible yellowing on the surface but
> slicht yellowing at the edges. All other hardening does not yellow paper.
> kees
Received on Thu Feb 3 09:03:39 2005