From: Richard Sullivan FRPS (richsul@earthlink.net)
Date: 09/19/01-10:17:37 AM Z
I have not had any recent experience using powdered pigments. Many years
ago in the late 60's I used powdered pigments. A little gum and a little
pigment in a small mortar and grind in with the pestle. At that time I
studied with a man named Jack MacDonald who previously had taught at
Mortensen's school in Laguna Beach Ca. in the 30's and he said that
Mortensen used to ball mill his pigments.
I am currently ball milling pigments for use in carbon printing and have
come up with what I call the Poor Boy's Ball Mill System (PBBMS) (Ok,
substitute the Boy's for the gender of your choice.)
You can with this system make enough enough gum pigments to last you the
rest of your life for the cost of a few tubes of W+N.
You will need:
a Bessler photographic developing drum roller. Check around they are about
25 bucks used.
A clean 1 gallon paint can. Paint stores have them for about 2 dollars.
Some pigment. www.sinopia.com.
Super duper source. 500 gm of lampblack costs $23.00. I think 10 kilos goes
for about $100.00. (It's amusing to think of printing with 10 kilos of
lampblack!) Italian burnt sienna is $12.50 per 500 gm. Of course there are
expensive ones that go for as much as $30.00 per 50 gm.
1 lb of marbles.
You will have a hard time finding them in toy stores anymore. Kids swallow
them so they are politically incorrect now. Go to a hobby store or Michaels
and go to the floral arranging section and they have a ton of them. They
are used for putting in vases for flower arranging.
Some Tween 20 or Polysorbate 20 full strength.
Procedure:
Put the marbles and pigment in the can. Add 1 ml of tween 20 for every 3 gm
of pigment. Add 5 ml of water for every gm of pigment.
I recommend a minimum of 100 gm of pigment since you are using a 1 gallon
can. Smaller cans may or may not work on the Bessler roller.
As for lampblack, it is intense so you can use 50 gm instead of 100 keeping
everything else the same.
Ok, you have the marbles, water, Tween and pigment in the can, put on the
lid. Pound it down tight!
Put it on the Bessler Roller. Let it roll for about 6 hours. The longer
the better.
When the time is up pour into a bottle.
Notes:
You will need to work out your water, pigment mix, and dichromate mix for
gum coating and printing.
You can adjust the ratios of water and pigment for ball milling. I just
give the above as a starting point. You may prefer to make a more
concentrated mix.
The Tween 20 is a dispersing agent.
Ball milling is often misunderstood. It is not to make the pigment finer
but is used to break up agglomerations. Pigment will clump in tiny
microscopic particles. The ball milling breaks up these particles. I've
observed the breaking of the agglomerations under a good microscope and yes
the ball milling breaks them down.
How fine a mix of pigment do you need to make a good gum print. I dunno.
I can say that Jack MacDonald and Mortensen were avid fans of ball milled
pigments. This may be overkill but it is sure fun.
--Dick Sullivan
At 07:07 PM 9/17/2001 +0000, you wrote:
>I have not used powdered pigments with Gum but have used them a great deal
>with Casein printing.
>Please feel free to contact me off list if you have any questions.
>
>Rosae
>
>_________________________________________________________________
>Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
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