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Metoda kolodionowa w fotografii i konserwacja negatywów kolodionowych

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Garztecki J.

Ochrona Zabytków

1971

issue 1

25-34

The wet collodion photographic process developed in 1851 was used by Polish professional photographers still as late as about 1880. The chemical features involved within this process are highly complicated as to their nature for reactions occurring in emulsion during its sensitizing are many-sided and as the collodion method has been abandoned already several years ago they have not been investigated exhaustively enough. Thus it can be said that the problem of preservation of collodion negatives confines itself to slowiug-down of processes resulting into decomposition of nitrocellulose forming an essential component of emulsion during the process may be observed a spontaneous eduction of nitric oxide, and besides to protection of negative glass plates against the harmful chemical effects exerted by environment in which they are stored and also against the contaminations from atmosphere. As the first and highly important preventive measure inhibiting the self-destruction of nitrocellulose should be quoted storing of negatives at the constant and as low as possible temperatures and relative humidities at the same time providing them with adequate ventilation to remove the gaseous products of decomposition. The temperature not exceeding + 18°C and humidity of 40 to 45 per cent may practically be considered as satisfactory. Under these conditions the limits of collodion negative life may be estimated as high as for some hundred years. Nevertheless, it is necessary to keep in mind that negatives covered with varnished emulsion prove to be considerably less durable. The environmental protection as its chief objective should have the eliminating from the negative store atmosphere the nitric and sulphuric oxides as well as hydrogen sulfide and ammonia (i.e. industrial contaminations) peroxides evolved by the softwood, floor polishing pastes, oil paints, varnishes and also some cosmetics. All the above-mentioned gases are causing decolonization of picture produced on plates by deposits of silver compounds or are leading to formation of stains on negatives. Another important factor is the quality of paper used for wrapping the stored negatives. To this purpose should be used paper manufactured from pure cellulose and having neutral reaction. Both the envelopes and boxes should be prepared without adhesives to prevent the harmful chemical effect of glues used for their manufacture. The cases for storing negatives should be made of metal sheet and provided with holes enabling their adequate ventilation. As the most abundant collection of collodion negatives in this country may be listed that including over 5,000 pieces representing the 19th-century views of Cracow, portraits of Cracow personalities, folk types, monuments of the town’s ancient art and s.o., constituting once a property of an atelier owned by the outstanding photographers family of Kriegers. It is quite obvious that the above-mentioned collection not only requires the care as the museum piece but also should be copied in whole on the modern photographic materials thus enabling to perpetuate the historical heritage it contains as its subject.

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1 Ochrona Zabytków

1 Garztecki J.

1 1971

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Metoda kolodionowa w fotografii i konserwacja negatywów kolodionowych