> Judy,
>
> I noticed in one of your posts to the alt photo list that you said the
> following:
>
> I'm just finishing a round of tests of 3 gelatines with 3 hardeners & 3
gums with
> 2 hardeners as size on various papers. For the particular gum emulsion I
> used, paper with no added size was *far* better in most cases. That may
> have been because the emulsion I used was thick, had a lot of pigment."
>
> I curious what paper did you use? What type and concentration of pigment did
> you use? Every time I try anything but double gelatin sized and formalin
> hardened paper, I end up with horribly stained prints. I am always looking
> for an easier way to do gum prints.
Mostly I'm using watercolors, Rowney, Daniel Smith, Winsor Newton. Each
color is different. I use a lot of pigment -- again each pigment has
different covering power, and density, but maybe a gram total pigment
with 40 drops gum, 40 drops saturated am di, 20 drops distilled water, is
average. (A while back I posted a formula for continuous tone one-coat
gum using mix of Indigo & Indian red. April or May, maybe.)
I find that the most reliable (tho hardly the most prestigious) paper for
no added size is Strathmore Bristol Drawing. This is for one-coat gum,
remember. Many others will work if you use a gum-rich mix, including Rives
BFK, a smooth hard surface Fabriano (one of mine has watermark FP4),
Buxton, etc. Others have spoken for lanaquarelle. Many papers will print
one coat with the right pigment, provided the paper hasn't been wet. (Or
would -- did I mention everything went to hell in handbasket this week?)
But each color-mix is different, and length of soak is a factor. I must
also add that heat & humidity -- ie, the ambient climate -- is another
factor (grrrrr!!!!). Test under a 21-step.
> I wonder could it be the type of gum arabic that I have been using? I have
> used for years, and with good success, the commerically available
> lithographers gum (as stated on the bottle "100% pure gum arabic"). What
> kind of gum do you use?
Since the weather changed I know nothing..... But until last week
I used & was very satisfied with the thicker (nominally gum-14) RBP gum
that I made a post about some 2 weeks ago (including phone #).
But if your gum isn't giving you clear whites without size, try mixing a
50% gum from powder. Also turn on the airconditioner (grrrrr!!!!).
And note that it's easier with more gum, less dichromate. Also, dilute
the dichromate. Don't use saturated.
Of all the size combinations possible, I have found Knox's gelatine with
a glyoxal hardener the best. Knox used without hardener stains. I have
tried harder gelatines, including the deionized ossein. I couldn't get
either the pigskin or the kosher bone to work -- tho they worked *worse*
with hardener, for whatever reason.
And whoever it was looking for glyoxal -- you need a friend at Fisher
Scientific. Tho I suppose Amend, Fluka, other chemical houses have it
too. Regular photo suppliers don't. It's tough for private party to
get, not because it's dangerous, but the way these companies work. If
you have a university connection, use your brownie points. Now maybe B&S
will stock it....
Judy