Effect of Light on Modern Digital Prints - Photographs and Documents

Abstract

This project examines the lightfastness of prints created with the most commonly used digital technologies (inkjet, color electrophotography, dye sublimation and digital press) along with prints created using traditional technologies (color photography, black-and-white electrophotography and offset lithography). The inclusion of traditional prints provides benchmarks for collection care professionals to better gauge the significance of the results. In this study, prints were subjected to two types of lighting used independently to simulate daylight through window glass and artificial indoor illumination. Five aspects of light damage were assessed: fade in the mid-tone neutral, fade in the darkest neutral tone, paper yellowing, changes in paper gloss and text readability. In general, digital prints were less sensitive to light than traditional prints; but each digital printing technology produced at least one sample that performed worse than its traditional benchmark in at least one of the aspects of light damage studied. Therefore, it is recommended that cultural heritage institutions strive to provide the most benign environment possible, taking display practices currently in use for traditional prints as a minimum starting point for the care of digital prints. Close monitoring for signs of change is also recommended.     

TESTING ADHESIVES FOR THE CONSOLIDATION OF PAINTINGS

Abstract

In the course of a program to develop adhesives for the consolidation of paintings it was found necessary to: (1) define the aims of the research, (2) design tests which would provide information on the mechanical performance (effectiveness) of the adhesives, (3) design tests which would help eliminate adhesives with qualities hazardous to paintings. This paper describes only the tests on the mechanical performance of various adhesives: (1) adhesion to paint films, (2) adhesion to conventional and newly developed lining supports, (3) cold flow of lining adhesives, and (4) rigidity of lining laminates. Formulations of the newly developed adhesives are given.     

Mitigation of light-induced damage on modern digital prints: Photographs and documents

This study is part of a larger research project dedicated to digital print preservation issues – the Digital Print Preservation Portal (DP3). This work quantifies the potential of glazing materials to mitigate different types of light-induced damage – colorant fade, paper yellowing, changes in paper gloss, and loss of optical brightening agent (OBA) function – that occur to digitally printed photographs and documents when on display. Prints were subjected to xenon lighting to simulate daylight through window glass in a series of arrangements: without glazing, with plain framing glass (soda-lime) in a sealed or unsealed package, and with UV blocking glass in a sealed or unsealed package. Sealed packages served the purpose of isolating the samples from atmospheric pollutants, known to contribute to the deterioration of certain print types. In this study, the use of UV-filtering glass protected prints from colorant fade, paper yellowing, and paper gloss change to an extent. Protection conveyed by plain glass was less comprehensive and less effective than UV glass. Neither type of glazing was able to keep the OBAs functional by the end of the light exposure. It was also seen that light-induced damage to digital prints is due not only to UV radiation, but also to visible light, and that different digital prints may be more vulnerable to one or the other. Protecting sensitive prints from UV radiation and budgeting the amount of light they may be exposed to should be essential to any print display policy in order to ensure longevity.     

Light-induced cracking and abrasion of inkjet prints: Damage and mitigation

This study is part of a larger research project at the Image Permanence Institute dedicated to digital print preservation issues – the Digital Print Preservation Portal (DP3). Previous DP3 studies determined that certain digital print types are prone to cracking and/or abrasion, and that factors such as low relative humidity, pollutants, and light increase the brittleness of the ink-receiving layer of some inkjet papers. The purpose of this investigation was to explore if light also increases the propensity of inkjet prints to abrade, and to examine the potential of framing glazings to mitigate light-induced physical damage (cracking and abrasion) by attenuating some portion of the UV spectrum. Inkjet papers and prints were subjected to xenon lighting (to simulate daylight through window glass) without glazing, or in sealed framing packages with plain framing glass (soda-lime) or UV filtering glass. Before and after light exposure, brittleness, and abrasion resistance were evaluated independently using two tests: ISO 18907 (Imaging materials – Photographic films and papers – Wedge test for brittleness) and a rub test utilizing a Sutherland® Rub Tester. In this study, exposure to light increased the cracking and/or abrasion tendency of some specimens. The use of UV filtering glass reduced this light-induced propensity in all cases. Plain glass protected all samples from at least one of these two types of surface damage, but was less effective than UV glass. Light-induced brittleness and sensitivity to abrasion were mostly, though not exclusively, caused by UV radiation. It was also seen that some prints may become brittle and/or prone to abrasion in the absence of image fade. Budgeting the amount of light these objects can be exposed to, protecting them from UV radiation, and handling prints with caution especially after exhibition, is essential in order to limit physical damage.     

Framing photographs,denying archives: the difficulty of focusing on archival photographs

This article pursues the varying understandings of the photograph in archival literature. An in-depth review of the scholarship uncovers several possible reasons why archivists and those writing about photographic archives apparently continue to struggle with the photograph, including: the sheer difficulty that photographs as an elusive medium present; past debates about photography in art history, history, and archival literature; and the challenges that the photograph as an evasive document presents to the contradictory nature of archives themselves and to conceptions of archival science. Having evolved from an understanding of photographs that conflated content with meaning to postmodernist notions of contingent and plural meanings in which photographs participate, archival writings on the photograph hold promise as they begin to tread the waters that Schwartz charted in the last 15 years. This paper follows that historical progression in order to trace the discourse on photographic archives that has emerged over the past three decades.

Original and reformulated BEVA® 371: Composition and assessment as a consolidant for painted surfaces

Abstract

Many natural and synthetic products have been used for the consolidation of paint layers, but none have been thoroughly tested for this application. This is apparent for most of the synthetic and semi-synthetic adhesives for conservation, many of which are pure polymer resins and dispersions adapted from other industries. They were not specifically formulated with the appropriate properties for conservation, nor do they take advantage of some of the more recent developments in adhesive technology. BEVA^® 371 is unique among adhesives used for consolidation treatments, as it is a multi-component mixture and was designed specifically for the conservation field using the best technology available at the time. However, the main focus of the research was its application as a lining adhesive. Thus, optical properties and stability, specifically color stability, were not thoroughly evaluated even though some lining applications that were first recommended could have benefited from this type of investigation. This paper will discuss the development of BEVA^® 371, the chemistry, and roles of each component, and address a practical concern about the tack behavior of its replacement formulation, BEVA^® 371b.     

The Use of Moisture Barriers on Panel Paintings

Abstract

Deterioration of paintings is effected by chemical, physical and biological agents. Activity of these agents generates mechanical stresses which result in cracking, cupping, cleavage and flaking of the paint film. Internal mechanical stress appears to be primarily responsible for premature or drying cracks in paint. Stresses external to the paint cause age cracks which penetrate both paint and ground. The literature explaining the origin and characteristics of these cracks is reviewed. Although premature cracking can only be avoided by instructing the artist in proper use of materials, age or mechanical cracking can presently be prevented by environmental controls and careful handling. Present methods of reinforcement of paintings in general only partially stabilize them against environmentally generated stresses. Further research appears necessary for more complete understanding of the stresses old paint can withstand and of the forces exerted by the shrinking and swelling of textile and wooden supports. Search for and testing of more physically and chemically inert support materials are suggested.     

Understanding the gum dichromate process in pictorialist photographs: A literature review and technical study

Abstract

In the late 1800s, pictorialist photographers favored a diversity of photographic techniques, including the gum dichromate process. Sometimes superimposed over other photographic images such as platinum and silver prints, the gum dichromate process utilizes a light-sensitive mixture of gum arabic, pigment, and a potassium dichromate solution hand-applied onto a sheet of paper and exposed to light while in direct contact with a negative. The definitive identification of this process has proven to be a challenge due to many variations and intermingling of techniques used by photographers of this period. This research began with a search through the historic literature, followed by the creation of test samples based on historic recipes, and the X-ray fluorescence analysis of these tests. The identification of pigments and the presence of chromium have been associated with the gum dichromate or other dichromated colloid processes in the past. Research results reveal that the presence of chromium may have more complex sources, requiring a more discriminating approach and a modified protocol for the identification of gum dichromate photographs.     

Evaluation of Conservation Treatments Applied to Salted Paper Prints,Cyanotypes and Platinotypes

Abstract

As the great majority of photographic prints have a paper support, their conservation has been based on conservation treatments traditionally used by paper conservators. It cannot be assumed, however, that these standard treatments, that are employed on paper without any problem, will give comparable results on photographic prints. The effects of mechanical cleaning, solvent cleaning, wet cleaning, bleaching and deacidification on salted papers, cyanotypes and platinotypes are investigated and discussed. The treatments were separated into those that gave clearly negative results and should be rejected, and those that should be studied in depth before accepting them as suitable. It was shown that the use of some types of bleaching and deacidification agents can be very dangerous in the case of plain paper prints. Cyanotypes proved to be the most sensitive to any treatment method and platinotypes the most resistant.     

'Diasec' and Other Finishing Techniques - Investigation of Accelerated Light Fading

Abstract

A study of the accelerated light fading behavior of face-mounted color photographic materials has shown that alterations on the surface of the materials influence their fading characteristics. With the help of spectral density measurements it became apparent that the application of materials such as silicone rubber, adhesive film and acrylic sheeting, but also laminating films, onto the surface of the prints accelerated the degradation of the colorants, especially the yellow dye, in chromogenic materials. In the case of silver dye bleach materials, however, the opposite effect was observed. The influence of the material combination on the stability of face mounted color photographic prints was demonstrated to vary considerably. In order to better assess the inherent damage potential of the materials themselves, these were examined by means of instrumental analysis and measurements of pollutant gasses. Besides off-gassing compounds such as acetic acid and changes in pH caused by aging of the adhesive, face-mounting with a rigid plastic sheet (acrylic glazing) also affected the respective fading behavior of the various materials that were tested.     

Modelling the lifetime of colour photographs in archival collections

Abstract

Colour photographs are among the most vulnerable materials in archival collections, making the development of tools for assessment of their lifetime in storage of particular interest. However, for this to be possible it is necessary to have a holistic understanding of what affects the lifetime of an object. Based on the existing knowledge of the effect of environmental conditions and material properties on lifetime of prints, this work focuses on the determination of end-of-lifetime using a value-based psychophysical approach. This research, carried out using a series of stakeholder workshops, showed that while assessor background does not significantly affect the end-of-lifetime determination, the nature of the images does. Isochrones, curves linking points of equal lifetime at paired environmental conditions, are defined. Based on these, a practical photographic lifetime calculator is presented, integrating dose-response functions with end-of-lifetime considerations. This tool, based on stock modelling principles, allows collection managers to input material stability data about the chromogenic prints in their collection and then investigate the effect of environmental scenarios on the collection. A case study of a collection at The National Archives, UK is also presented.     

Differential thermal expansion as a cause of salt decay: literature review,experiments, and modelling of micro and macro effects on Ançã limestone

Salt decay is one of the harshest, most frequent, and more complex types of decay of porous materials in built heritage, including natural stones, ceramics, and mortars. In this article, we address the mechanism of thermal expansion, which is one of the least studied, yet most controversial, of those proposed over time to explain salt decay. We present a review of scientific literature on the topic, followed by a study of the effects of thermal expansion on a specific material, the well-known Ançã limestone. The study included experimental measurement of the linear thermal expansion coefficient of the Ançã, both in its natural state and with varying contents of sodium chloride, sodium sulphate, or sodium nitrate. The results show that this coefficient: (i) is significantly higher when the stone is contaminated with salt; and (ii) scales approximately with the amount of salt contained in the stone pores, regardless of the type of salt. Based on these results and on modelling of damage modes at the microscopic and macroscopic levels, respectively, we conclude that thermal expansion can cause powdering, disaggregation, or other types of decay consisting of internal loss of cohesion. However, it is not likely to cause exfoliation of salt-loaded layers.     

Infrared Ellipsometry Analysis of Heritage Photographic Prints

Focusing on the photographic archive of Julian Carrillo (Mexico), we study and characterize the photographic processes of a set of 13 photographs dated between 1884 and 1925. By using infrared spectroscopic ellipsometry, we classified a selected set of photographs according to its kind of binder. Thus, we recognized for each photograph, the presence of proteins, and therefore, the particular photographic process. Furthermore, we have identified the presence of baryta layer, the use of plasticizer, and the eventual coating utilized to protect the photograph, whose composition was based in natural organic components, mainly shellac, beeswax, or camphor.     

Establishing the value of socially-created metadata to image indexing

There have been ample suggestions in the literature that terms added to documents from Flickr and Wikipedia can complement traditional methods of indexing and controlled vocabularies. At the same time, adding new metadata to existing metadata objects may not always add value to those objects. The potential added-value of using user-contributed (“social”) terms from Flickr and the English Wikipedia in image indexing is compared with using two expert-created controlled vocabularies—the Thesaurus for Graphic Materials and the Library of Congress Subject Headings—without those social terms. Experiments confirmed that the social terms did add value, relative to terms from the controlled vocabularies. The median rating for the usefulness of social terms was significantly higher than the baseline rating, but was lower than the ratings for the terms from the Thesaurus for Graphic Materials and the Library of Congress Subject Headings. Furthermore, complementing the controlled vocabulary terms with social terms more than doubled the average coverage of participants' terms for a photograph. The relationships between user demographics and users' perceptions of the value of terms were also investigated, as well as the relationships between user demographics and indexing quality, as measured by the number of terms participants assigned to a photograph. Participants with more tagging and indexing experience assigned a greater number of tags than did other participants.     

Library Provision of Intellectual Access to Open Access Journal Articles

ABSTRACT

Academic libraries provide intellectual access (discovery and procurement) to the full text of electronic journal articles through traditional library technologies like discovery layers, link resolver software and knowledge bases. These technologies mainly rely on accurate title-level metadata to successfully deliver journal articles to library users. Open Access articles pose a difficulty for many participants in the e-journal supply chain, including libraries and publishers, as Open Access status is a property of the article, not the title. A review of the literature examines: the impact of Open Access on intellectual access through traditional library technologies, current proposed solutions, and emerging technologies.     

Book reviews

Abstract

Using written accounts of observed methods and materials of Tibetan paintings as well as examination of numerous examples, the techniques of Tibetan paintings, especially paintings on cloth, are discussed. Brief mention is made of the regional styles of Tibetan painting, since the techniques used in the production of these paintings apparently vary throughout Tibet and China. Various types of supports are mentioned and analyses of the types of cloths are given. The preparation and materials used in the ground, pigments and preliminary drawings and prints are discussed. The iconometrics of Tibetan painting are mentioned, since the total conception of the object is dependent upon them.     

Between Policy and Practice: Archival Descriptions,Digital Returns and a Place for Coalescing Narratives

ABSTRACT

The Strathfieldsaye Estate collection at the University of Melbourne Archives is discussed in relation to recognising, protecting and reclaiming Koori (First Peoples of southeast Australia) heritage. The settler collection includes early 1900s photographs of Koori people within two distinct albums – a family album that includes a series of studio portraits of Koori adults and children, and an album depicting Koori families on Ramahyuck Aboriginal Mission Station. In the past, these albums have been defined by, and limited to, traditional archiving practices excluding Koori interpretation, authorship and social context. Restoring Koori ownership and authorship of intangible heritage plays a large part in consolidating ancestor photographs with Koori perspectives of identity and culture.     

Cinnabar reviewed: characterization of the red pigment and its reactions

Abstract

In the majority of cases, the red color of cinnabar on objects of cultural heritage is well preserved, though turning black is often claimed and has been the subject of investigations. To evaluate conditions for the stability of the pigment and understand the reactions, in this paper the problem is approached from various viewpoints. First of all the natural form cinnabarite is compared with the artificially prepared pigment vermilion. This establishes a differentiation of types in terms of quality, depending on structural impurities. With regard to the pigment's reactions influencing the discoloration, the most commonly mentioned environmental factors, such as radiation or halogens, are evaluated. In relation to various usages, the pigment's structural stability is then viewed in connection with adjacent pigments, glues, and the substrate, which may lead to a brown or black coloration or even the release of mercury, whereas the color is preserved in most cases when used on lime or in ink and lacquer. Due to the materials’ properties, attention is drawn to the fact that discoloration to a brownish-black is not necessarily a sign of damage and harmful reaction products, but may indicate good preservation of the painted material, provided that the mercury can be bound in the substrate.     

Electrotypes in science and art

Abstract

The history of the production of electrotype copies is discussed in the context of the Victorian demand for reproduction of art of all kinds utilizing plaster of Paris, photographs, copies of old prints, as well as electrotypes, predominantly of copper. The philosophical reasons for the valuing or devaluing of electrotype and other copies are discussed. Electrodeposition of metals was used for an extraordinary number of different purposes in the Victorian period, and the general craze for electrotypes made their production very popular, being produced by men and women alike of many different backgrounds. By the Edwardian era, the need had subsided and an art historical reaction to the concept of copies had begun, with photography becoming more common. Examples of the use of electrotypes for photographic tinthotypes, as well as forgeries, discovered during conservation assessment at the Getty Museum on a plain Roman cased mirror which had been augmented by an electrotyped profile head addition, and samples from electropatterns from the collections of the Victoria & Albert Museum in London, are discussed in terms of the range and type of microstructural morphology displayed by electrotype copies.