How I Make A Gum Print

Each gum printer seems to find his or her own way of making a gum print. Although the basics remain the same, every gum printer uses slightly different techniques. Here is how I make my gum prints.

The Picture

I start with either a conventional photograph or a digital file. I look for subjects that resonate in some way emotionally for me and that have a fairly simple composition.

Landscapes often represent an emotional territory for me, so I have numerous gum print landscapes. Dogs, which are symbolic for me of innocence or a time in my childhood, also frequently appear in my prints.

I print a negative of my picture onto transparency film that is the size of the print I want to make.

The Paper

I use a heavyweight, acid free watercolor paper, mould-made in France from 100% cotton.

I first soak the paper in very hot water to shrink it. Then I let it hang to dry.

Next, I size the paper in a gelatin solution to keep the pigments from soaking into the fibers of the paper.  I often put 3 separate coats of gelatin size on the paper.

Exposing

I mix potassium dichromate, with gum Arabic in equal parts and then mix in a watercolor pigment. Many gum printers use watercolors from a tube, but I like to use natural dry earth pigments from Italy and France, which give a more subtle color range. The amount of pigment I use varies, depending on the particular layer and look of the print.

I brush the solution onto my prepared paper and let dry.

Once dry, I tape the negative on top of the print and place it under an ultraviolet light source.

Developing

After the print has been exposed, I remove the negative and put the print in a water bath. The lightest parts of the negative float away quickly. Other parts of the print will more slowly and gradually lose some or all of their pigment, depending how long I leave the print in the water.

Knowing when to pull the print from the water bath is one of the key decisions for a gum printer. If I pull it too soon, I won’t get details in the dark areas. If I pull too late, I will only have a flat, ghostly print.

I can also brush away or wash away pigment, allowing me finer control of the highlights.

When I like the look of the print, I take it out of the water bath and hang it to dry. Once dry, the pigments are completely fast and will not come off again.

This is the process for one layer of pigment. I will put on anywhere from 4 to 9 layers of pigments, repeating this whole process each time. With each layer I must decide what color to use, how much pigment to use, how long to keep it under the lights, how long to let it sit in the water bath, what areas to wash away, and how much color to keep in each layer.

Each print may take as long as a week to make.

Why I am a Gum Printer

One of the reasons I fell in love with this process is because every gum print is unique, with its own color and tonal atmosphere. Even when I try to recreate a print, using the same negative, and try to reproduce the same order of colors, I get different results.

To me, gum prints have an emotional quality that is mysterious and appealing. The prints look like how I think a memory might look if it could be put on paper. There is also a strong narrative suggestion in my gum prints, and each one feels charged with meaning  that I only begin to understand as I create it.

It is commonly said that making gum prints takes a week to learn and a lifetime to master. Learning to adjust and use the many variables, and developing my own individual signature, means gum printing is a constant process of discovery.

Despite their delicate look, gum prints are virtually impervious to humidity and sunlight. Gum prints made at the turn of the century show no signs of fading, and one gum printer hangs his gum prints in his glass-enclosed pool house, knowing that neither the high humidity nor the direct sunlight will cause any damage to them.