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This information is reprinted from the Beginner Topics
column of Hand Papermaking Newsletter #63 (July, 2003).
To learn how to order Hand Papermaking bi-annual magazine
and quarterly newsletter, click
here.
Color and Pigments
Summer is such a colorful time of year. I am reminded of
being in Walter Ruprecht’s wonderful facility outside of
Harare, Zimbabwe, and seeing a rainbow of papers, but no
pigments. He made all of his wide variety of colored papers
from bright cotton clothing.
This is certainly one method of making colored paper.
Whatever fiber color you begin with will remain
approximately the same in the finished paper. This approach
assumes, however, that you have access to conventional
production equipment.
The recycling of papers will also generate color. If you
are a “blender” papermaker you can add brightly colored
tissue paper which bleeds very quickly, producing
vibrant--though fugitive--colors.
But for those of you papermakers who want to understand
more about “serious” color, and find the whole subject very
mysterious, let’s take a closer look. Papermaking color
comes in two primary (no pun intended) types: pigment and
dye. The simplest way to understand the difference is to
imagine the paper fiber being like a straw. When given a
dye, it sucks it up and changes the fiber to the given
color. On the other hand, pigments just sit rock-like next
to the fiber; the human eye sees the color, but the color is
beside--not in--the fiber.
This difference has an impact upon permanence as well.
Paper is hygroscopic: it “breathes” in moisture from the
environment. Our environmental moisture is charged with
chemicals of its own. When these chemicals in the air reach
dyed fiber, there is a stronger reaction, or change, than if
the moisture contacts a lump of pigment. Therefore, papers
colored with pigments are more permanent than papers colored
with dye.
Pigments are often dispersed in liquids. These dispersing
agents come primarily in two types: water and oil. For
example, we have watercolor paints and oil paints. Hand
papermakers sometimes use aqueous dispersed pigments
available from special suppliers. Artist’s colors that are
water based can also be used by simply mixing the tube color
with water and adding it to the pulp. Dry pigments are
easily purchased, and these need to be ground with water and
sieved through fine mesh before using.
Once the pigment to be used is ready, the second major
issue comes into play. Paper pulp has a negative chemical
charge and so does the pigment. This means they do not want
to mix. Papermakers need to add a chemical agent to make the
pigment bond to the pulp. This substance is called retention
agent. It has a positive charge and will help to hold the
pigment to the fiber. It is available from hand papermaking
suppliers.
Small amounts of retention agent added to the pulp cause
the pigment to hold to the fiber, make the fiber a more
intense color, and allow the surrounding water to run clear.
The proportion of retention agent to fiber varies greatly.
Red and yellow are the hardest colors to retain, while
browns and blues are easier. Proportion is a matter of
experimentation, but it is worth the effort because the end
result is a beautiful palette of colors to use confidently
in your work.
I encourage you to experiment with a variety of pigments
and create a summer rainbow of color. I will continue this
introduction to color by discussing dyes in the next
newsletter. So don’t let your subscription lapse!
Copyright 2003 Hand Papermaking, Inc.
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