Re: My own PVA glue sizing experience became: dark reaction in gumemulsion

[phritz phantom <phritz-phantom@web.de>]

hey loris,
> In any case, I still don't think to let the emulsion sit that much,
> for the sake of consistency - especially in a calibration/test
> setting.
>   
as i said, this was only by coincidence. not that the whole list thinks 
my problems come from extremely sloppy technique. i'll admit to being a 
little sloppy, but usually within the boundaries.
i coated a test strip to be dried, exposed and developed immediately and 
i kept the emulsion to see whether the temperature of the gum solution 
(took it right out of the fridge) has an influence or not. and it was 
meant to be used within an hour or two. then something had me distracted 
and i didn't use the emulsion until the next day.
the strange thing now is, that both fresh emulsions show intense stain, 
while the old emulsion has significantly less.
i'm now setting up a new space for drying the coated papers, which is 
not in the bathroom. there the ambient humidity will hopefully be more 
constant, and i'll see what happens.

regards
phritz

> 2009/10/28 Keith Gerling <keith.gerling@gmail.com>:
>   
> > > "BTW, it's not a good idea to keep the coating solution (gum/pigment +
> > > dichromate) for a day. You'll get "dark effect". Just mix enough for
> > > immediate use."
> > >       
> > Loris, have you actually observed "dark effect"  in wet emulsion?  I'm
> > skeptical whether is actually exists.
> >     
>