Some viewers of my carbon printing videos have asked me to write out some of the formulas for the carbon printing materials and processes I demo in my videos. Well, here you go.
These formulas will get you started. However, keep in mind that they can, and should, be changed as you develop aesthetic preferences and want to change your materials to match. For example, different pigments have varying tinting strength and will require different concentrations. A less concentrated gelatin sizing for art paper will provide a less glossy finish. To retain more or less moisture in the tissue, or change the pliability, the sugar can be varied. So, take these formulas as starting points and adjust as you learn.
Note: In the formulas, the percentages of ingredients are intended for calculating the weight of the ingredient as a percentage of the total volume of the solution. For example, a 10% gelatin solution would require 100 grams per liter and 1.2 percent pigment would be 12 grams. Distilled water is recommended, particularly if your water is alkaline. If you are going to spend hours upon hours making prints from your tissue, it's worth using water you know will be good. It also dissolves ingredients better.
Glop for making tissue
India ink is a good pigment to start with. It is perfectly dispersed, easy to mix, and does not require you to do any extra straining or filtering of the glop after mixing. It produces prints with deep blacks, warm undertones, and a glossy finish. I use Speedball because it is easier for me to buy. It can be bought off the shelf at many art supply stores. Black Cat can be ordered from Dick Blick. Speedball is more concentrated and seems a bit more glossy in finish. The pigment percentages below are simply ones I have used in the past based on their relative concentration.
- 10% gelatin (250 bloom or greater)
- 1.2% Speedball india ink or 1.6% Black Cat india ink
- 4% sugar
- Water to make
- 25 ml of isopropyl alcohol mixed 50/50 with water to make 50 ml (an optional ingredient added at the end which can help dissipate bubbles more quickly if you intend to use the glop shortly after mixing)
Art paper sizing
A 7% gelatin solution is easy to coat, sets up quickly to allow you to hang the paper to dry, and gives a reliable printing surface if the paper is thoroughly and consistently coated and the gelatin is hardened. Thinner or less concentrated sizing will provide a more matte finish but will be more prone to developing frilling or blisters on the print when developed.
Hardener for gelatin sized art paper
This is a topic of it's own see my blog post.
A 3% solution of sodium or potassium metabisulfite will clear the residual dichromate stain from the print. Soak the print for approximately 3 minutes or until the stain clears. Wash in clean water for several minutes afterward. The clearing solution can be reused.