Pressure printing is an alternative image-making technique by which a flexible plate (backing sheet) is placed behind the press sheet and run over a type-high, inked surface. The resulting image is made up of a combination of haloing ink and varying degrees of pressure from the backing sheet. A variety of textures and patterns can be achieved through experimentation with materials such as tape, cut/torn paper, fabric, lace, leaves, etc. This technique is often used over an inked solid, but any type-high surface could work equally well. The technique is most similar to low-relief collagraph, however, the plate must be flexible if it is to be run through a cylinder press, and it is not actually inked up; the image is transferred via the pressure it imparts to the press sheet.
History of Pressure Printing
The first book published on the subject was Experiments in Relief Printmaking, written by Charles William Smith and published by The University of Virginia Press in 1954. Other prominent printers and printmakers, Valenti Angelo, Mallette Dean and John S. Fass successfully used this process for book illustrations in the 1940s and ’50s. In his book Charles Smith described the process:
The term “direct impression” as used here means that the block has been engraved… and color transferred directly from the engraved block to the printing paper. The make-ready or indirect impression is different in that the pressure is applied to the reverse side of the paper causing the image from a block to the printing paper. This impression is never as clear and sharp as the direct impressions.
Variants on this process were used in the process of making Japanese woodblock prints during the experiments days of the Moku-Hanga movement in the 1920s and ’30s, which is how the idea may have been introduced to western printmakers. Smith mentions this process as possible both by hand-printing and machine-printing.
Some refer to this process as pressure printing, a term coined by Barbara Tetenbaum in 1989, however another term for the process is stratography, derived from ‘strata’ meaning layered material. Print and papermaker Joe Wilfer is said to have coined the term. Joe studied and worked at the University of Wisconsin, Madison before moving on to Pace Editions in New York. His work can be further explored in the catalog The Joe Wilfer Show: Collaborations in Paper and Printmaking. Another term, zurichtungdruck, is used in Germany.
Advantages of Pressure Printing
Pressure printing can be useful for quickly creating a shape or image for a project that desires something a little different than the typical lino/wood cut. You save time and money by not having to carve a large linoleum or wood block for an image that will only be used once. The image and the backing sheet are the same, this means no having to draw and think in reverse. You are also able to get precise registration with this process, allowing for unique multi-color prints.
The backing sheet is a flexible sheet, typically a sheet of paper, that is either cut to create a negative stencil, or layered with more paper or other materials to create a positive (raised) plate. A negative plate allows for higher contrast, whereas the positive image is useful when creating a pattern or a more representational image. The positive image works best when printing on a solid flat of color, however caution must be taken when printing a positive image, because it can damage the printing block if the backing sheet is too thick.
The backing sheet can be run directly behind the press sheet for the most contrast and tightest registration. For larger editions, taping the backing sheet to the tympan is a time saver. Mylar may be used as a way of protecting the tympan when printing, allowing for ease of taping and removing of backing sheets. The backing sheet may also be registered behind the tympan. Placing the backing sheet underneath the tympan can result in less contrast. A general rule of thumb is: the thicker the backing sheet, the higher contrast the image.
There will always be a little bit of noise (or chatter, imperfections in a blank area such as carving marks from linoleum or wood), but adjusting bed height or amount of packing should create the desired effect. The lower the impression and amount of ink, the less noise.
The thickness of the press sheet can also affect the pressure printed image. Thinner paper will achieve the most variety in image and contrast, but a thicker paper (such as Lettra or chipboard) will produce more subtle results.
Use extra caution when pressure printing on linoleum or wood type. The stencil can easily impress into the surface. If you are creating a positive image, be aware that any additional thickness is effectively increasing the packing. Lowering the press bed, or removing the necessary amount of packing can solve these problems. Transferring a texture onto the block can also create a desired effect. For example, by running a piece of lace through the press with a block of linoleum in the bed, you will be able to transfer that texture onto the block.
There are limitless possibilities as to what can be used as a backing sheet. Organic materials, such as plants and leaves, create beautiful images. Stitching directly onto paper, or using a textured fabric can create and interesting pattern or line. Bold shapes can be made by cutting paper, vinyl stickers or even a variety of adhesive tape (anything from Duct to Scotch).
Pressure printing is not well suited for fine detail, the image tends to be soft, and intricate designs are easily lost. With fragile backing sheets, packing tape or contact paper is a good way to insure that the design will hold up throughout the edition. Another method is to use spray adhesive or PVA glue to adhere the stencil to a sheet of thin paper.
Reductive pressure printing
Because registration is so precise, reductive printing and using multiple blocks are ideal techniques to use when pressure printing. Using one backing sheet and multiple printing blocks allows you to build an image from several passes on the press. This is achieved by placing the same backing sheet, in the same place, behind each press sheet as it runs through the press.
Reductive pressure printing, or slowly removing more and more of your backing sheet for each run through the press, is easily done with tight registration.
The example “Tandem” shows a 3-color print.
- The first pass is a solid block printed with light blue ink, with a solid piece of paper as the backing sheet.
- The word “tandem” is drawn on the backing sheet and removed with an xacto knife. Counters in the type are held in place with packing tape. This is the new backing sheet used to run the medium blue pass.
- After the medium blue pass has been printed, the shading on the type is removed from the backing sheet, and the spaces between letterforms are held in place with packing tape. This is the backing sheet used for the navy color that is run on the same solid block for the previous 2 colors.
- Experiments in Relief Print Making by Charles W. Smith, published in 1954