LETTERPRESS HALFTONE PRINTS

Color Letterpress Halftone Postcard with Image from Tangier, Morocco (PSAP, n.d.)  

Definition

Letterpress halftone prints are mechanically reproduced prints (of original photographs or other images) using ink dots of varying sizes on a paper support. Letterpress halftones may be black and white or multi-colored (two, three, or four-color halftones).  (PSAP, n.d.)

Process

The letterpress halftone printing process is a combination of two processes.

The first simplifies the subtle tones of an original photograph into dots of varying sizes. The original image is re-photographed through a screen (grid of parallel horizontal and vertical lines) in the camera lens. The finer the screen, the finer the resolution will be. This first step creates a negative image composed of larger and smaller dots that can be used to for the second part of the process.

The second step translates the negative image onto a relief plate, which consists of raised dots. This relief plate is then inked with the raised areas catching the ink. The ink is then pressed onto the paper under pressure. Small dots create more detail but do not print as easily (except on glossy, chemically coated paper). Newspapers use larger screens because newsprint is more coarsely textured.  (Griffiths, 1996) (PSAP, n.d.) (Kaplan & Stulik, 2013)

In translating a gray-scale image, usually only black ink is used on a white paper ground. Halftone images rely on the optical blending that occurs in the human eye. The eye under normal viewing distance (and without aid of magnification) blends the black dots and white paper to approximate the range of gray values found in the original photograph. (Kaplan & Stulik, 2013)

Multi-colored halftone prints follow the same process, but with several overlapping prints using separated colors.

Identification

Letterpress halftone prints are identifiable by the halo effect – “squeeze out” or “ink rim” – formed around individual dots. This effect occurs in the printing process when more ink is squeezed out around the edges than in the center of each dot.  This “ink rim” can be easily seen through a loupe or low-magnification microscope. Sometimes the dots run together to create a waffle like pattern. Older halftone prints have coarser dots and, hence, are lower-resolution images. (IPI, 2015)

Low-magnification Microscopic View of Letterpress Halftone (PSAP, n.d.) 

Inventors

Letterpress halftone prints have no single inventor. Prominent contributors to the process include:

• Henry Fox Talbot (British, 1800-1877)
• Georg Meisenback (German, 1841-1912)
• Frederic Ives (American 1865-1937)
• Max Levy (American, 1857-1926)

(Kaplan & Stulik, 2013)

Many 20^th-century photographers relied on the letterpress halftone process for reproducing their work. Photographer Ansel Adams (1902-1984) used letterpress halftones (along with lithography and photogravure) to create ink prints for his many publications. The photographer describes some of the advantages and challenges of getting high-quality prints from this mechanical process. Letterpress halftones are capable of producing quality prints when the smallest textured screens are used, but even these prints are not comparable to the continuous tones of a photographic print, which depends on light and chemical reactions.  (Adams, 1983)

Ansel Adams (1938), Sierra Nevada  

 Applications

Letterpress halftone prints were commonplace from the 1880s through the 1960s and are still are in use today in some applications.

Halftone prints were most commonly used in commercial printing in the early- to mid-20^th century.  Applications included mass reproduced items such as calendars, postcards, newspapers, magazines, etc. The process was also used for books and posters. (PSAP, n.d.) (Kaplan & Stulik, 2013)

1953 Magazine Image (IPI, 2015)

Preservation

Letterpress halftone prints are often more resistant to deterioration than original photos. The quality of paper has much to do with the life of the halftone print. The water-insoluble inks used in halftone printing typically do don’t fade. The paper however may yellow, warp, or crack when exposed to too-high or too-low humidity. Rough handling or poor storage may result in tears or other damage.

Preservation recommendations include acid-free folders and sleeves (either conservation quality paper or plastic – uncoated polyester, polyethylene, polypropylene, or cellulose triacetate) in hanging files or archival storage boxes. Files may be stored in cabinets made of enameled steel, stainless steel, or anodized aluminum. Wooden cabinets should be avoided.

Prints should not be displayed longer than 3 to 4 months. Light levels should be low and images should be protected from direct exposure to natural light. Display cases and frames should be acid-free and of preservation-quality materials. (PSAP, n.d.)

Bibliography

Adams A. (1983). The Print: Book 3 of the New Ansel Adams Photography Series. New York, NY: Little, Brown and Company.

Griffiths A. (1996). Prints and Printmaking: An Introduction to the History and Techniques. London: The British Museum Press.  

Image Permanence Institute (IPI). (2015). Letterpress Halftone Prints. Graphics Atlas. Rochester Institute of Technology. Retrieved from: http://www.graphicsatlas.org/identification/?process_id=45

Kaplan A. & Stulik D. (2013). Halftone. The Atlas of Analytical Signatures of Photographic Processes. Getty Conservation Institute. Retrieved from http://www.getty.edu/conservation/publications_resources/pdf_publications/pdf/atlas_halftone.pdf

Preservation Self-Assessment Program (PSAP). (n.d.). Photomechanical Prints. University of Illinois at Urbana-Champaign. Retrieved from: https://psap.library.illinois.edu/format-id-guide/photomechanical