The Diversity of Digital Print Types, Materials, and Performance

Digital Print TechnologiesIPI’s survey of the professionals in the cultural heritage field also determined that there is currently no common definition for the term digital print. In fact there are contradictory definitions in use that make clear communication difficult.  For example, some respondents defined digital prints as:

  • only those digital prints that resemble traditional photographic prints
  • only items printed with a digital printing device (such as an inkjet printer)
  • only prints originally captured by a digital camera or produced through software on a computer) regardless of how it was ultimately printed
  • some felt that prints on light-sensitive photographic papers could be consider digital prints if they were exposed using a digital photo-printer while others felt that they could not

Despite this confusion in the field, IPI needed to develop a clear and consistent definition for the purpose of the projects. For our purposes, the term digital print refers to:

The class of prints created using the most common modern, non-impact printing technologies:  inkjet, direct dye thermal transfer (“dye sub”), and electrophotographic. Pictorial images generated with silver-halide, light-sensitive papers using laser or LED exposure from digital files are also included. Digital prints can include pictorial images, text, line art/graphics or any combination of the three. Printing substrates are limited to paper (uncoated and coated) or polyethylene laminated papers (also referred to as resin-coated or RC papers).

Since that definition was developed in 2007, we have come to appreciate that it is usually better to avoid the use of the term digital print when referring to specific objects but instead describe them according to their own unique process such as inkjet or to an ever greater level of detail such as dye inkjet on porous-type photo paper. Using the more specific and accurate terms for the individual objects will help prevent confusion as to their origin and characteristics. It is still okay to use the term digital prints when referring to the overall array of printing techniques used today to create hardcopy from computers and other digital sources.

For further discussion on the issues surrounding defining the term digital print, see "What Do You Mean When You Say “Digital Print?" by Daniel Burge, Douglas Nishimura, and Mirasol Estrada, which was published in the Society of American Archivist’s Archival Outlook April/May 2009.

The problem of digital print preservation has turned out to be very complex. The simplest possible result of the project would have been that digital prints could be treated the same as traditionally printed materials using the same, current best practices. If this had proved to be true, then no new preservation skills and knowledge would have been needed by the field. We knew at the outset of the project that this would probably not be the case. What we weren’t prepared for was the truly great variety of digital printing materials available (printer types, colorants, and most especially papers) and the diversity of how these materials would respond to deterioration forces over time. In fact, the most complex possible outcome has occurred. Almost every digital print technology, sub-category, and colorant and paper variation ages differently from the others and may need individualized care strategies to maximize its usable life. This diversity of print performance has made it impossible to generalize the results for all digital prints. This only validates the importance of referring to individual objects not as digital prints but by their specific process.

Because any given collection will contain a variety of print types and no collection will be exactly the same as another, some collections, in aggregate, may appear robust, others weak, and still others mixed. Anecdotal experience and case studies will likely not provide adequate guidance on how to care for collections of these materials. Only a science-based data set, such as the one generated by this project that includes multiple examples of many of the various print materials, can provide valid guidance on how to properly care for these materials. This is one of the major contributions of this project to the field.