Fig 1; Unknown, date unknown Opalotype 383 x 280mm; From the collection of CCMC;
The Opalotype consists of almost any photographic technique as long as it used on opal glass. It was in use from the mid 1800's through to the1930's and most of the methods of photographic production that were used during the 19th century were tried out with opalotypes. However despite it's long-lived history, Opalotypes are sadly treated as a very minor side road of exploration by most of the photography history books and if mentioned at all, will be given only a one paragraph description. This disregard may have helped contribute to their poor state in contemporary collections.
This investigation began after viewing an opalotype portrait (fig 1) in the collection of Centre for Cultural Materials Conservation (CCMC) with a photographic image of a suited gentleman printed onto an opaque white glass plate 388mm high by 280mm wide. The image had added detail possibly in a watercolour or ink, having a slightly transparent quality. There is a considerable amount of image loss and staining. There is evidence of an oval vignette mount now missing with the exposed areas showing fading and light damage.
The image appears to be not quite photo, not quite painted-portrait but has a soft compelling quality to it, which is quite endearing, despite its sad state. There is something special about Opalotypes.
In this paper I will discuss the evolution of the opalotype with it's emergence from the miniature to its popularity as a framed portrait. I will talk about the material technology and development opalotype production. The chemistry of the gelatino-bromide emulsion technique will be examined as this is the most commonly represented in opalotype in Australian collections (Egunnike, 2007 p144). Finally, the types of degradation that occur because of the materiality of opalotypes will be discussed.
The Evolution of the Opalotype
The opalotype is a photograph made of almost any binder and any emulsion as long as the substrate is opal glass - otherwise known as milk glass. The Opalotype technique was first patented in 1857 and was still being commercially produced until the 1930's (Egunnike 2007 p143). It seems that the opalotype was used for some time to replicate the miniature portrait just as the ivorytype was being used. The early opalotypes were of similar size to the miniature and to daguerreotypes and ambrotypes. They were displayed in similar intimate display cases, or set in jewellery. The ground white glass was said to be well suited for coloured portraits possessing 'all he transparency and brilliancy of ivory miniatures' (Unknown 1 1864). Watercolour was commonly used for colouring and detailing these photographic images.
In Australia the opalotype became very popular during the 1880's through to the 1930's. These images were enlargements from negatives, rather than the small contact prints of earlier days, often up to around 300 x 250mm which were intended to be framed for wall hanging (Cox, 1990 p32). The Beginnings
Ivory had been a popular support for miniature watercolour portraits from the 1790's though to the early 1800's. These were quite expensive objects, which became less popular as more successful photographic techniques for portraiture developed (Verplanck 2004, p138). In 1855 JE Mayall in England, patented an artificial ivory from the newly invented celluloid. He used tinted collodion or albumen on the white celluloid and called the product 'ivorytype'. However the term ivorytype seems to have become a generic term for all photographs that used a white ivory-like support. Marcu Root describes in 1864 a compound of barytes and vegetable albumen, kneaded together, dried and polished, producing a surface 'of the smoothest texture and purest ivory colour is obtained, constituting an admirable recipient for the image' (Noye 1998).
A Mr Henry Brown of...