TERMIUM Plus^®

Fiche 1,  Justifications,  Anglais

Record number: 1, Textual support number: 1 CONT

Reciprocity effect. All photographic emulsions are subject to an effect often called reciprocity-law failure. The reciprocity law states that intensity of the illumination falling on a film times the exposure time equals the amount of exposure (E = I x T). This law does apply for most black-and-white films from exposure times of about 1/5 sec. to 1/1000 sec. and for colour films over a narrower range. Thus, where the law holds, an exposure of 1/60 sec. at f/11 is equivalent to an exposure of 1/30 sec. at f/16.  2, fiche 1, Anglais, - reciprocity%20effect

Fiche 1,  Justifications,  Français

Record number: 1, Textual support number: 1 DEF

Perte de sensibilité du film selon l'écart entre le temps choisi (lent ou rapide) et le temps pose standard (entre 1/8 et 1/1000 de seconde) d'un film donné.  3, fiche 1, Français, - effet%20Schwarzschild

Record number: 1, Textual support number: 1 OBS

Chaque type de film possède sa propre courbe de sensibilité. D'un écart trop important résulte un tirage sous-exposé ou présentant des dominantes.  3, fiche 1, Français, - effet%20Schwarzschild

Fiche 1,  Justifications,  Espagnol

Fiche 2,  Justifications,  Anglais

Record number: 2, Textual support number: 1 CONT

The tendency for slide and negative/print films to shift during long exposures is called "reciprocity failure". The different color layers and dyes of any film react to light at different rates, and film manufactures design their films so that the different dyes produce accurate overall colors during the most often used exposures, usually 1/30th of a second or faster.  3, fiche 2, Anglais, - reciprocity%20failure

Record number: 2, Textual support number: 2 CONT

Kodak T-Max 100 Pro is an extremely fine grain, high resolution film with slightly less red sensitivity than Plus-X. The film has little toe and lots of straight line in its characteristic curve. Shadow separation is excellent, but processing consistency is essential. Reciprocity departure characteristics are excellent, this film is therefore faster than a number of higher-rated films at exposure times of several seconds or more.  4, fiche 2, Anglais, - reciprocity%20failure

Record number: 2, Textual support number: 1 OBS

According to the reciprocity law, as long as the exposure (light intensity x time) remains constant the response of the emulsion is the same. Many photographic materials fail to follow this law at extremely long or short exposures; a proportionately greater increase in exposure may therefore be necessary to maintain the same negative density.  5, fiche 2, Anglais, - reciprocity%20failure

Fiche 2,  Justifications,  Français

Record number: 2, Textual support number: 1 CONT

[...] l'effet Schwarzschild, qui se fait ressentir lors de temps de pose longs et qui oblige à poser davantage que l'exposition théorique pour en obtenir une parfaite. L'effet Schwarzschild, aussi appelé écart à la loi de réciprocité, a toutefois moins d'importance en noir et blanc qu'en couleur [...]  4, fiche 2, Français, - %C3%A9cart%20%C3%A0%20la%20loi%20de%20r%C3%A9ciprocit%C3%A9

Fiche 2,  Justifications,  Espagnol