175th Birthday

In case you missed it, an interesting post by Larry J Schaaf, To the Calotype: Happy 175th Birthday! points out that it was “during this week in 1840 that Henry Talbot made the tremendous breakthrough that was to propel his negative/positive photography into the wider public arena.”

The discovery was that of the latent image, and the calotype process which utilised it was the first practical negative/positive process, the true forerunner of almost all photography that followed, at least up to the advent of digital. Schaaf’s discussion is an interesting one, pointing out that Talbot in that week realised the potential of the latent image, while both he and Herschel had previously seen the phenomenon as an annoying anomaly rather than something to be exploited, and that its significance in the daguerreotype – the mercury from the broken thermometer that revealed the image – had simply been accepted as a part of the process.  It is of course chemically very different, whereas the reaction of gallic acid – a substance that seemed to react in so magical a way that Talbot cut its name from his notebook to keep its secret – is essentially the same as that of metol, hydroquinone, phenidone and the other developers we came to rely on in later photography.

Schaaf also clarifies an issue that still foxes many who write about old photography, making clear that there are no calotype prints. The calotype was a process for making negatives, which where then printed as salt prints. There were good practical reasons for this. Some have to do with appearance, and calotype negatives seldom have the qualities of a good print, generally lacking something in contrast and maximum density as well as seldom having clean highlights, and often the colour is not attractive, but it was also a matter of practicality. Hand coated photographic materials lack the consistency of factory made products and required to be printed by inspection (with experience needed to judge the changes that processing would make.) You cannot inspect a latent image, and test strips are of limited use when one sheet may differ in speed from the next.

It wasn’t long before some factories began making materials in a more controlled fashion and when works were set up to produce prints in quantity the increase in speed made the use of the latent image and print development a great commercial advantage. By 1851, when Louis Désiré Blanquart-Evrard founded his Imprimerie Photographique in Lille, the albumen paper he made was consistent enough to allow development, enabling them to make several hundred prints in a day from a single negative rather than the handful – perhaps even only two or three – possible through printing out. But these developed prints were a rather cold grey and rather less attractive than those printed out which had finer silver grains which gave a warm brown, often slightly purplish tone. Gold toning improved their appearance somewhat.

It was only around thirty years later that print development came into more general use, with some of the new gelatin coated papers, and many photographers continued to use printing out papers, particularly for proof prints, well into the twentieth century.  They have of course more recently enjoyed something of a renaissance with the rise of interest in ‘alternative processes‘ in the 1970s and 80s, with which I dabbled for some years. But in the end I found photography far more interesting.

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