[alt-photo] Re: gum--different colors different coating problems?

[Loris Medici]

Uppermost and/or darker layers are harder to coat evenly, especially when
pigment concentration is strong.

I use phtalo too, and I didn't experienced any excessive staining or very
uneven application - unless it was mixes too strong. It's a very strong
colorant (and very transparent), therefore, you don't it too much of it. It
will wreak havoc with the color balance, if you use it too strong.

Just aim to finish the print within 5-6 layers (not 3!) it will be much
easier, IME...

Do you size the paper BTW?

Regards,
Loris.


-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org On Behalf Of
Charles Ryberg
Sent: Thursday, July 01, 2010 12:04 AM
To: The alternative photographic processes mailing list
Subject: [alt-photo] gum--different colors different coating problems?

    Paul Viapiano's beautiful prints inspired me to tackle gum, again.  By
looking at his, I determined that I had been using WAY too little pigment. 
I increased the amount of Hansa Yellow and got a lovely mixture which went
down on the paper like very high quality wall paint.  No brush marks, no
streaks, just an even yellow field.  My Perelene Red went down like cheap
discount wall paint.  Careful application and quick but thorough blending
gave me a satisfactory field.  But the French Ultramarine looks awful with 
streaks and brushmarks no matter what I do.  I tried    a little Tween     a

lot of Tween     increasing the gum proportion    increasing the water 
proportion     using everclear (95% ethanol) for half the water.  All ugly.

    Then I read that Paul uses Pthalo blue, so I tried that with some small
improvement but the Pthalo stains like mad--never gives me anywhere near
paper white.

    I really have to put the yellow down first because it is opaque and has
a reputation for making muddy colors if used second or third--so I can't do
gum over cyano.  Well, I suspect I can't, but I may try it out of
desperation though what the necessary acid prewash will do to FAB's gum
friendly size is dubious.

    Any suggestions?