Both ink and paint consist essentially of a pigment in a vehicle. Traditional black ink was typically lampblack in linseed oil. Linseed oil is one of several “drying” oils that take on oxygen from the air and polymerize to produce a tough skin, binding the pigment and paper.

Linseed oil which has been heated to 720–750 F° will no longer grease paper. Burnt plate oil and stand oil are not heated this high, and artist’s inks made with them are unsuitable for letterpress use. If you intend to make your own ink, buy the vehicle ready made from the inkmaker because heating linseed oil is dangerous. Use commercial black inks, which are usually made from synthetic resins. This gives the inkmaker control over the properties of the ink, and makes the ink consistent from batch to batch. You may have to try several inks to find a black you like; consult your local ink company if you have one. Use oil-base inks for quality work. Rubber-base inks may print satisfactorily, but their drying properties make them suitable only for imprinting business forms, numbering, proofing, etc., and they do not dry on coated stock. Special inks are available for printing on plastic or plastic-coated stock. If possible, tap out a little ink on the intended stock and leave it overnight to test drying and adhesion.

Some colors—reds and yellows especially—of commercially-manufactured ink are made with fugitive pigments, and tend to fade over time with exposure to light. Your ink manufacturer may be able to supply you with more permanent colors. Another expedient I have tried is the addition of permanent artist’s oil colors to the ink. Oil colors by themselves are short and buttery and dry slowly to a matte finish. Earth reds and yellows such as Venetian red and Naples yellow may not fade.

Ink Additives

  1. “Combination” or “three-way” drier to speed drying.
  2. Clove oil to slow drying. (I have not tried this although I can sometimes smell cloves in an ink. Perhaps available from your dentist: I believe clove oil is a local anesthetic.)
  3. Tack reducer to avoid picking on coated stock and improve coverage.
  4. Number eight litho varnish, or “body gum”, to increase tack.
  5. Artist’s wax medium. The surface of the ink will not dry as hard, but the ink will be less likely to penetrate the stock if coverage and impression are heavy. Make a trial of this before using.
  6. Some old recipes call for the addition of soap. I do not know what its purpose is. Perhaps it reduces tack.


An excellent book is Color and Culture by John Gage, published by the University of California Press. It is really a history of color.

Opaque white

A color is specified by a swatch in a swatchbook, uniquely numbered, and having printed with it the formula by which it can be mixed from standard base colors. The base colors are transparent, and the white component of the color comes from light reflected from the substrate. This system is designed for offset lithography. Because letterpress typically puts down an ink film thicker than offset’s, less light is reflected from the paper, and colors mixed from swatch formulæ very often appear too dark printed letterpress. For this reason, and for others I shall mention, I usually mix colors using opaque white ink. I can use the base colors specified by the swatch, in about the right proportions, and get the value I want by adding opaque white. This simplifies the mixing because the color of the ink can be judged in mass, without drawing out. I almost never weigh out colors—I estimate proportions by eye. It is often less wasteful of ink to begin with about the quantity of white you anticipate needing, and to add the colors. If a large or recurring job requires a special color, consult your inkmaker.

This method of mixing with opaque white works less well when mixing reds because the color pinks out; still, a little white, with perhaps a little yellow may work; browns sometimes purple out. Try these colors on press: sometimes color looks wrong on press but right on paper. Tapping out a little with your finger on the stock to be used for the job can help you judge its color.

A clean yellow or light green is difficult to achieve without several washups. Run the the color up on the press for a while to draw the residue of darker inks out of the rollers. A quick and dirty trick for grays is to run up opaque white until it turns gray, and then push it around with tiny amounts of other colors tapped on the rollers. If the gray becomes too strongly tinted with a color, add the complement to bring it back. When the color is right, a quantity of it can be mixed to match.

Using opaque white, the color is coming from the surface, not the depth of the ink. For this reason, changes in color during the run due to fluctuations in the amount of ink the press is carrying are minimized. Colors vary considerably under different lighting conditions; the customer is more apt to notice differences in coverage than exact color accuracy. Ghosting may be lessened with opaque inks because variations in the thickness of the ink film are less noticeable. Ink can also change in color or value on drying.

A grayed-out color can be made by using opaque white and the color’s complement. This seems sharper, or somehow more interesting optically than the same color mixed with white and black.

My personal opinion is that opaque colors accord more closely with the spirit and tradition of letterpress than do transparent colors. Lithography is a photographic medium in which the page is a window into another world (think National Geographic). Transparent inks are suitable in four-color process. Opaque inks have a less coy or illusional interaction with the surface of the paper, and are more idiomatic.

Buy as little ink as you can and mix the colors you need. Inks accumulate, and any established shop will have a shelf or cupboard of leftover dabs of ink in paper or plastic cups, mixed up over the years.