What is the gumoil process

Writer and photography / Terri Cappucci

Terri Cappucci explains what the gumoil process is and how she prints.  

What is the gumoil process?  It is a photographic printing process that uses a sensitizing gum arabic mix and oil paint, to create a handmade photograph. It is more detailed than this, but it is a start when explaining to someone for the first time.


The final gumoil print
The final gumoil print


I enjoy this tactile process known as gumoil, for a few reasons.  In the age of technology, photographs have become so easy to come by and are very uniform. They are either in a digital format on a screen, or the photographer has the ability of making multiple prints on a home printer.  It is so easy for anyone with a camera to have unlimited photographs printed. Unless a particular process is involved, they are all done the same way and none are unique to each other. In my own photographic work, I find that I want and need something different.  If I do not have my hands involved in the process, it will not feel like my creation.  From the lens to the final print, my hands need to be as involved as my vision.  With that said, I do work with digital on occasion, but I am really a film and alternative process photographer.  Gumoil is very challenging and can frustrate from time to time, but that is the part that makes the results personal to me. The outcome will never be the same in any two prints. It makes the work one of a kind and each print, unique.  After seeing some of my recent prints, Anna Ostanina (a fellow artist who was instrumental in my learning this process) said to me, “Terri, you have your own handwriting style in this process”.  Those words really summed up what I had been looking for explain what I wanted to express in my art.  I want my work to have my own thumbprint in and on it.

A little history that I found online about the gumoil process.  It was invented by Karl P. Koenig (1938-2012), in 1990.  He originally called it “ Polychromatic Gumoil Photography”.  Since this time, other photographic artists have taken his process and continued to explore, leading to multiple workflows and methods to get similar and even better, results. Koenig tends to remove his paint with more of a rubbing process. His book “Gumoil Photographic Printing” is no longer available, but it can be found used.

I also came across Anna Ostanina’s work. She removes the paint with less rubbing and more water. It appeared easy when I saw her images and videos, but after speaking with and learning from her, it was not that easy.  She had researched and tested the right combinations of paint, paper and steps, that would give her the paint removal process and final print results that she was seeking. She is a master of her craft and a gracious teacher.

When I make my gumoil prints, I am using a combination of workflows that I learned from both Karl Koeing and Anna Ostanina.  With that in mind, my supplies and mixtures may be different.

Here is a list of what you need along with the image you want to use:

*** Please be cautious using Potassium Dichromate. Do not inhale or get on your skin. Always wear gloves and a respirator face mask when working with this chemical. ***

  • Rubber gloves
  • Face mask
  • Inkjet printer
  • Overhead transparency film.
  • Distilled water (this is if you need to mix Potassium Dichromate)
  • Gum Arabic
  • Potassium Dichromate (12%-13% saturation)
  • Watercolor Paper 310gsm or thicker is best.
  • Oil paint.  As Koenig says in his video, use a professional grade oil paint. I would suggest making your first print with a Lamp Black or Ivory Black. When you are ready to fine tune your prints, you can explore other colors such as Payne’s Gray, Burnt Umber, or Cobalt Blue, etc.
  • Paint Brush
  • Sponge
  • UV light (The sun works well at certain times of the year, depending where you are located. If you have an exposure unit or want to make one, that will work too)

Start by making an inter-positive of the image you want to use. This is a black and white positive print from an ink jet printer, on to an overhead transparency film. I then take my mixture of potassium dichromate (13% solution) and gum arabic mixture 1 part potassium dichromate and 2 part gum. With that said, you may find that you need to mix more gum depending on the paper you are using. I have mixed anywhere between 1.5 and 3.5 gum with 1part potassium dichromate.  With a softer brush, coat one side of your watercolor paper in the area you want to expose your image on. I usually leave a 2-inch border around my paper.  Apply it evenly and be consistent. I apply the coat in lower light, but I dry my paper in the dark. Usually in my darkroom, but I have used a cabinet or even a drawer depending on the paper size. This is important because if you let it dry in the light, you are exposing that area at the same time.  That needs to be avoided until you are ready to expose it.


Apply sensitizer
Apply sensitizer
Print interpositive
Print interpositive

Once dried, I take the paper out and put the inter-positive that I made of my image, on top of the now dried, sensitized area. I then expose it to the UV light. Exposure times will vary depending on the suns strength if you do it outside, or the kind of exposure unit you are using. I use a Nuarc exposure unit and exposure time is between 3-4 minutes.  After being exposed, you will see the details of your image. As soon as it done exposing, soak the paper in water immediately. This is the developing process. This will stop the exposure and remove the rest of the yellow sensitizer. I soak for 15-30 minutes. This is a delicate part of the process as the gum swells on the paper and needs to be left to dry without being wiped or touched. It holds the part of your image with details and can remove or distort your image if it is wiped off while still wet.  Take the print out of the water and dry your image. I use a drying rack I made or just hand on a clothes line.  If you dry outside, be careful with wind.  I have had little particles and bugs that have stuck to the gum.

After exposure
After exposure
After soaking
After soaking

Once the print is completely dry, apply the oil paint.  I don’t apply it thick because it is messy when it comes off.  If you do add too much paint, try to smooth it out with a soft cloth or a quality paper towel. I use Viva paper towels because they don’t leave a lot of “fuzz” behind.  The shadow areas will begin to show through the oil paint. This is when the print can be placed in water and gently removed with a sponge. Be gentle or you can wipe off the image, take off too much paint or damage the paper. There is another part of this process called “etching” where a bleach and water mix will allow a 10-15 second etch bath and then repeat the process of soaking, drying, applying paint and rinse and remove paint with a soft sponge again. I don’t always etch my prints, but I will if I want to more detail in my image.


Apply oil paint
Apply oil paint

A few things I have learned that have made a big difference in the success of my gumoil workflow. When I get the results I am pleased with, it will be in part because of a combination of water source, paint brand and quality and the water color paper being used. Sometimes there is a different combination of paint brands and paper that work, depending where I am. I have found that in my studio, one combination of paper and paint will work better with the water. If I am in a different location, I may have completely different results and have to use a different paint and paper combination. I am not sure why, but my theory is that it has to do with the water treatment in different cities and the water reaction to the entire mix of sensitizer and paint, depending on the location where the print is being created.Other gumoil artists may do things differently. After talking with others who make gumoil prints and trying many different techniques, papers, paints, exposure times, and steps, I have developed a workflow that gives me as close as I can get to having consistent results. With that in mind, it can change very quickly because this is still an unstable process.  With that said, I am seeing more consistency with the new mix of paper and paint that I have been using.Here are a few videos I have made of my process:

Terri Cappucci is a photographic artist who has been working with the gumoil process as well as other alternative processes. Her work has been recognized and exhibited worldwide. More about her work can be found at www.terricappucci.com

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