An investigation into the effects of solvent content on the image quality and stability of ink jet digital prints under varied storage conditions.

Increasing numbers of galleries, museums and archives are including ink jet printed materials into their collections, and therefore displays. There is evidence that the instability of these prints is such that images can suffer deterioration in print quality or in extreme cases, a loss of information over an extended period of time. This is shorter than the period typically required for perceptible deterioration to occur in other paper-based artworks. The image stability of prints is affected by a number of factors some of which have already been studied. However the role played by the solvent in the loss of image quality has yet to be explored.

This research will investigate the effects of solvent content which may increase/promote the loss in image quality of the hard copy prints when stored or displayed under a range of temperature and humidity conditions.

Building on an extensive literature survey, laboratory based research will be carried out on a range of contemporary ink jet printed materials. The materials selected will include all types of ink jet systems that use process colour inks on both swellable and non-swellable substrates, including fine art digital print papers. Samples will be subjected to a variety of defined treatments designed to reduce or remove the solvent content. The extent of solvent removal will be established using fourier-transform infra red spectroscopy and thermal analysis techniques, and will be monitored for enclosed prints through gas chromatographic headspace analysis. Following these treatments, samples will be stored under defined temperature and humidity conditions that are intended to simulate conditions found in both well and poorly controlled archival and domestic environments. Some samples would be stored in the open, some contained within non-permeable envelopes; these will be subject to periodic monitoring. Some samples will remain within sealed enclosures until examination. Samples will be stored for up to two years.

Changes in image quality will be assessed objectively from density, gloss and colorimetric measurements. The last will be carried out and compared on a macro and micro (sub-millimetre) scale. Optical and scanning electron microscopy will be employed to establish the movement, both lateral and vertical, of the dyes and/or pigments. Perceptible variations in print quality will also be assessed subjectively using panels of observers.

Following analysis of the prints, recommended procedures for long term preservation of prints will be made which are relevant to heritage organisations responsible for the conservation and preservation of digitally printed artefacts.