Office and Reprographic Printing Cheatsheet

"Ink" on Paper Processes (Carbon black or blue aniline ink)

Carbon Copy (1870s – 1980s)

Carbon copy onionskin paper
Onionskin paper. Note the paper texture. Taken from an image of the ILIR Library Teamsters Contracts Vertical File, 1948-69 (35/3/415) from the University Archives. Image courtesy of the University of Illinois Board of Trustees.
Image/Text
Carbon-based ink; aniline-based ink (VERY COMMON)
Identification
Almost always a single color but may be of any color. Image/text appears faint and dull. Carbon copies are on a semi-translucent paper (e.g. manifold, onionskin); typewritten originals are on opaque plain paper.
Preservation
  • Color inks are dye-based. Are water soluble as well as light and heat sensitive.
  • May be printed on low-grade wood pulp paper.

Stencil Copy (1880s – 1970s)

Blue inked stencil copy
Blue ink stencil copy. Taken from an image of the ILIR Library Teamsters Contracts Vertical File, 1948-69 (35/3/415) from the University Archives. Image courtesy of the University of Illinois Board of Trustees.
Image/Text
Carbon-based ink; aniline-based ink (VERY COMMON)
Identification
Printed on rough, porous plain paper. May appear similar to hectographs and spirit duplicates. Has clotted or spotty characters. Oil-based ink will produce an oily halo.
Preservation
  • Early color inks contain aniline dye. Are water soluble as well as light and heat sensitive.
  • Overall stable; preservation risk depends primarily on quality of support material.

Typography (c. 1902 – c. 1970)

Letterpress printed sign
Letterpress typographic print. Courtesy of the Illinois History and Lincoln Collections, University Library, UIUC, University of Illinois Board of Trustees.
Image/Text
Carbon-based ink; aniline-based ink
Identification
Difficult to distinguish from typed originals and from stencil copies, hectographs, lithographs, and spirit duplicates. Characters are embossed. Oil-based ink will produce an oily halo.
Preservation
  • Early color inks contain aniline dye. Are water soluble as well as light and heat sensitive.
  • Overall stable; preservation risk depends primarily on quality of support material.

Offset Lithography (Office) (1906 – present; office use declines after 1960s)

Image/Text
Carbon-based ink; aniline-based ink
Identification
May be difficult to distinguish from stencil copies.
Preservation
  • Color inks are dye-based. Are water soluble as well as light and heat sensitive.
  • Overall stable; preservation risk depends primarily on quality of support material.

Impact Print (1960s – present)

Impact print
Impact print. Courtesy of the Illinois History and Lincoln Collections, University Library, UIUC, University of Illinois Board of Trustees.
Image/Text
Carbon-based ink; aniline-based ink
Identification
Viewed under magnification, text/image is made up of a distinctive pattern of evenly spaced dots embedded within the paper.
Preservation
  • Color inks are dye-based. Are water soluble as well as light and heat sensitive.
  • Overall stable; preservation risk depends primarily on quality of support material.

Dye-Ink Transfer Processes (Violet, blue, or black ink; smooth surfaced)

Hectograph Copy (Office) (1878 - 1970s)

Hectograph
Hectograph. Taken from an image of the ILIR Library Teamsters Contracts Vertical File, 1948-69 (35/3/415) from the University Archives. Image courtesy of the University of Illinois Board of Trustees.
Image/Text
Aniline-based ink
Identification
Typically "crystal violet" or blue ink with little to no embossment. Printed on bright white, smooth, glossy paper. May appear similar to spirit duplicates and diazo prints.
Preservation
  • Color inks are dye-based. Are water soluble as well as light and heat sensitive.
  • Avoid alkaline enclosures.
  • Copy paper usually contained gelatin or alum rosin sizing; high heat and humidity will cause accelerated deterioration (e.g. yellowing, embrittlement).

Spirit Duplicate (1923 – 1970s)

Various spirit duplicates
Spirit duplicate copies. Image courtesy of Ian Batterham.
Image/Text
Aniline-based ink
Identification
Characteristic "crystal violet" ink color (although blue or black were sometimes also used) displaying little to no embossment. Paper surface is typically smooth and glossy. May appear similar to hectographs.
Preservation
  • Color inks are dye-based. Are water soluble as well as light and heat sensitive.
  • Avoid alkaline enclosures.
  • Paper may be yellowed; image may be faded with low contrast.

Photographic Processes (Metallic emulsion on specially coated paper)

Photostat Copy (Office) (1909 – 1970s)

Photostat office copy
Photostat office copy.
Image/Text
Photographic silver (emulsion)
Identification
White text on black background. May have rough edges or odd dimensions as a result of being cut from a roll. Qualitatively similar to a negative photo print, it may exhibit silver mirroring.
Preservation
  • Sensitive to light.
  • Oxidation may result in silver mirroring.

Diffusion Transfer (1940 – c. 1970)

Various diffusion transfers
Diffusion transfer copies. Image courtesy of Ian Batterham.
Image/Text
Photographic silver (emulsion)
Identification
Manufacturer’s backprint may be present on verso, which might also hold marks made by blotchy waterstaining or fingerprints. Cut corners are an identifying characteristic of Kodak papers. Specially coated paper is likely thicker than similar copy processes. Paper tone is light brown or gray/buff.
Preservation
  • Sensitive to light.
  • Oxidation may result in silver mirroring.
  • Residual chemicals may cause staining or embrittlement.

Dual Spectrum (1963 – early 1970s)

Various Dual spectrum copies
Dual spectrum copies. Image courtesy of Ian Batterham.
Image/Text
Photographic silver (emulsion)
Identification
Light blue flame emblem may be present on verso. Paper ground is pinkish or cream colored with dark-red brown or black image. Specially coated papers will vary from flimsy to bond weight.
Preservation
  • Sensitive to light.
  • Oxidation may result in silver mirroring.
  • Slight acidity of residual silver salts may cause yellowing of support paper over time.

Electrostatic Processes (Carbon black or CMYK toner)

Electrostatic Xerox Copy (Office) (1949 – present; oversized copies from c. 1960 – present)

Electrostatic Xerox copies
Electrostatic Xerox copies. Image courtesy of Ian Batterham.
Image/Text
Pigment-based (carbon black) toner (VERY COMMON)
Identification
Monochromatic black, high-contrast image/text that appears to sit on the surface of the paper. Edges of original scanned document may be visible in margin of copy if not aligned exactly during copying.
Preservation
  • Overall stable; preservation risk depends primarily on quality of support material.

Color Photocopy (1973 – present)

Various color photocopies
Color photocopies. Image courtesy of Ian Batterham.
Image/Text
Pigment-based color (CMYK) toner
Identification
CMYK toner appears to sit on the surface of the paper. Often difficult to distinguish a color photocopy from laser and inkjet prints.
Preservation
  • Sensitive to light and water; exposure may cause image fading.
  • Overall stable; preservation risk depends primarily on quality of support material.

Laser Print (Office) (c. 1978 – present)

Laser print document
Laser print document. Note the absence of imaging/scanning artifacts.
Image/Text
Black or pigment-based color (CMYK) toner
Identification
Toner appears to sit on the surface of the paper. In contrast to electrostatic (Xerox) printing, laser printing is usually made square on the page. Does not typically exhibit artifacts from scanned documents.
Preservation
  • Pigment-based color inks are more stable than dye-based, but they should still be considered sensitive to water and light.
  • Overall stable; preservation risk depends primarily on quality of support material.

Other Processes

Copybook and Roller Copy (1840s – 1950s)

Iron gall ink copybook copies
Iron gall ink copybook pages. Image courtesy of the Chicago History Museum: John Kirk letter book, John Kirk collection, vol. 3, from the manuscript collection.
Image/Text
Aniline dye ink; Iron gall ink (COMMON)
Identification
Thin, translucent paper.
Preservation
  • Aniline dyes and iron gall ink are unstable. Color inks are dye-based, water soluble, light and heat sensitive.
  • May be rendered brittle by iron gall ink.
  • May be printed on low-grade wood pulp paper treated with sulphuric acid, which can cause paper to be embrittled.

Diazo Print (Office) (1930s – present; technical use, 1920s - 1970s; office use, 1940s - 1970s)

Diazo prints in a bound volume
Diazo prints (in a bound volume). Note the tonal differences of the front and back sides. Image courtesy of Ian Batterham.
Image/Text
Azo dye ink
Identification
Ammonia odor, which may have transferred to adjacent documents
Preservation
  • Residual chemicals in paper cause yellowing and embrittlement.
  • Sensitive to light, which will cause dye-fading.
  • Off-gassing due to residual chemicals in paper; should be stored separately.
  • Avoid alkaline enclosures.

Thermal Print / Thermofax (1950 – present; office use, 1950 – 1980s)

Thermofax
Thermofax. Taken from an image of the ILIR Library Teamsters Contracts Vertical File, 1948-69 (35/3/415) from the University Archives. Image courtesy of the University of Illinois Board of Trustees.
Image/Text
Leuco dye (composition varies due to patented chemistry)
Identification
Thin sheet, with discoloration on recto (front), white on verso (back). May be difficult to identify due to variety of ink colors and types of support papers.
Preservation
  • Yellowing, embrittlement, and image darkening occurs rapidly due to chemical paper coating even if kept in dark storage.
  • Sensitive to high RH; heat will catalyze paper darkening.
  • Preservation photocopying recommended.

Electrofax (1954 – 1980s)

Electrofaxes
Electrofaxes. Image courtesy of Ian Batterham.
Image/Text
Pigment-based toner
Identification
Shiny layer of white pigment (zinc oxide) layer coating the support paper. Copies made after 1977 will display the electrofax logo, a pale yellow outline of a cactus, on the verso (back).
Preservation
  • Zinc oxide coating may crack or flake.
  • Sensitive to heat and light; exposure will cause dye fading.
  • Preservation photocopying recommended.

Carbonless Copy (NCR) (1954 – present)

Carbonless copy paper detail
Carbonless copy paper (detail).
Image/Text
Leuco dye ink
Identification
Pre-printed forms; colored papers.
Preservation
  • Dye-based ink fades quickly.
  • Yellow and embrittled paper due to chemical coating.
  • Preservation photocopying recommended.

Inkjet Print (Office) (1984 – present)

Image/Text
Dye- or pigment-based
Identification
Typically full-color with no scanning artifacts. Unless printed from a scan, print matter will be square on page and typically exhibit no artifacts due to its computer-generated origin.
Preservation
  • Ink should be considered sensitive to water and light.
  • Overall fading of the image may occur from light exposure, especially of magenta ink.
  • Preservation risk largely dependent on type and quality of support material, which can vary widely.