My thoughts on making a Gum Dichromate Print:
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Modern photo technology has created a whole new group of amateur photographers, but some still prefer the timeless photo techniques of Gum Dichromate Printing. There is something so satisfying about making gum prints in a dark room with the raw tools of the trade similar to how it was done over a hundred years ago. I personally find the gum printing process to be extremely challenging and equally as rewarding. You can watch the artwork develop before your eyes. |
What is Gum Dichromate Printing? The process is relatively simple but very difficult to master. There is no one right technique for gum printing and every person develops their own unique methods. The process is an art form and even mistakes turn out to be some of the most interesting prints. There are many variables to the gum printing process which guarantees that there will never be two identical gum prints. "Gum Bichromate is a 19th century photographic process, initially patented in 1855 by the French photographer and inventor, Alphonse Poitevin. While modern practitioners have undertaken a variety of improvements, in essence it remains broadly unaltered from its 19th century origins. The gum process enables the subtle use of varying applications of colour and the use of physical techniques to remove and adjust colour and texture. Images can be made in one colour; three colour - to produce a full colour image, or different layers of colour can be used to create 'free-form' colour images. The final gum bichromate print consists of hardened gum arabic and pigment which is as permanent as the paper it is printed upon." http://www.gumphoto.co.uk/gallery.html
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WARNING: The information on this site is opinion only. There is no one right way to make a Gum Print, but there are wrong ways which can cause personal harm. Dichromate chemicals are dangerous and should be handled with care. Each person should make themselves familiar with proper handling procedures. The chemical can be fatal if ingested and will cause eye and skin irritation on contact. Please click link below for more information: http://wiki.answers.com/Q/What_are_the_dangers_of_potassium_dichromate |
To make a gum print you will need some basic supplies:
1. Gum Arabic: white/gray powder that is mixed with water to make a syrup liquid.
2. Ammonuim or Potassuim Dichromate: orange granular powder which is the light sensitizer.
3. Watercolor Pigment: artist grade watercolor paints.
4. Paintbrushes: small to medium size brushes
5. Graduated Cylinder: small accurate measuring cup for chemical mixing.
6. Artist Paper: sturdy enough for several soakings, preferably cotton fiber.
7. UV Light Source: plain old sunshine works well.
8. Vacuum Frame: two pieces of heavy glass will work (no vacuum needed).
9. Rinse Trays: a shallow container large enough to soak and develop the paper.
Optional:
10. Sizing: Gelatin or acrylic coating to protect the paper (gives clear highlights)
11. Ink-jet printer: if negatives are not available you can make your own with an ink-jet and oil.
12. Hair dryer or Heat gun: to speed up the drying process.
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How It's Done? Detailed instructions with illustrations can be found here
To make a Gum Print you must first decide what kind of print you would like to make. There are dozens of different ways to make a print, but the important thing to remember is that gum prints are an art form with vast latitudes. Prints can be as simple as a leaf laid on the emulsion and exposed to sunlight, or as complex as several colors with dozens of burns under a UV lamp. If you decide to make simple contrast prints you probably will have most of the supplies you need around the house. Multi color prints generally require negatives and additional equipment, but the results are worth the effort.
Prepare the Paper: The paper is pre-shrunk by soaking it in very hot water and then air dried. This will preserve the shape and register of the sheet to be used with multiple ink layers.
Sizing of the Paper: This is done to keep excess pigment from staining deep into the fibers. There are several ways, but brushing gelatin on is the most popular. I prefer to use acrylic spray (a little more temperamental to use, but much easier to apply).
Apply The Emulsion: The emulsion is the light sensitive liquid which is applied to the paper. It is made by mixing water, gum arabic, a dichromate (potassium or ammonium), and watercolor pigment. The mixture is brushed onto the pre-shrunk and sized paper and then allowed to air dry.
Prepare the Negative: Gum prints require full size negatives which are expensive to produce, but there is a way to make them with an ink-jet printer. The printed sheet is simply oiled by rubbing baby or vegetable oil on the paper. The oil will make the negative transparent to UV light.
Burn the Image: The negative is placed on top of the emulsion coated piece of paper and sandwiched between two glass plates (or placed in a vacuum frame). The negative & paper are then exposed to UV light.
Develop: The paper is soaked in warm water which rinses away the non-exposed areas of emulsion leaving a positive image. The process is repeated until the desired image density is achieved.
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