How does the Gost system work?

Gast · 2005-07-07T09:43:31+00:00

Hallo, wie funktioniert die russische Empfindlichkeitsbemessung, ist das gleich ASA oder gibt es Unterschiede, ich stelle die Frage nur interessehalber, w...

Gast

Hello, How does the Russian sensitivity rating system work? Is it the same as ASA, or are there differences? I’m just asking out of interest, as I can’t find any clear information on this in the literature I’ve consulted. Thanks Hermann

Gast

Hermann, The simple answer is yes; the complicated one is that it depends. In the early 1980s, GOST was equivalent to ASA, in theory. Before that, GOST was based on log D 0.2 above the film’s base grey tone, whilst ASA was based on log D 0.1; therefore, GOST was always approximately 1/3 stop higher than ASA. 16 GOST 20 ASA 32 GOST 40 ASA 65 GOST 80 ASA 130 GOST 160 ASA 250 GOST 320 ASA and 45 GOST 50 ASA 90 GOST 100 ASA 180 GOST 200 ASA There were no other films available. Then it was adjusted With 16, 32, 64, 125 and 250 GOST equalling ASA And in 1991 there were new films again: 25, 50, 100, 200 and 400. Now both of the latter ranges are available. But I find that our films have higher speed than American film of the same number. Oleksander I hope you can understand this, though I rather doubt it.

PhilippReichmuth

How does the Russian sensitivity rating system work? Is it the same as ASA, or are there differences? I’m just asking out of interest, as I can’t find any clear information on this in my literature.

GOST is ASA * 0.9, so 90 GOST = 100 ASA, 360 GOST = 400 ASA, etc. (GOST/ASA/DIN comparison table ). In practice, you can usually just equate it with ASA; it’s close enough. Presumably, the shutter speeds on your Russian camera are less accurate than the variation in speed.

PhilippReichmuth

Hi Oleksander, Thanks for letting me know about the change; I wasn’t aware of that.

So it has been adjusted With 16, 32, 64, 125 and 250 GOST equivalent to ASA

Does that mean that all ‘newer’ 250 GOST films suffered from overexposure when used in old cameras or with old light meters? The deviation from 250 to 320 ASA is, after all, quite substantial. Or was the new scale perhaps only used for colour films?

American photographic film?

Didn’t you use any GDR or Czechoslovakian films (in Ukraine, I assume, given your name)? I saw ORWO films lying around in the TsUM in Tashkent in 2003/4, the only ‘socialist’ product alongside an old Soviet 45 GOST black-and-white film. Unfortunately, I didn’t pay attention to the ORWOs’ speed.

Gast

Phillip, if, say, your camera is set to 250 GOST (pre-1981 model), that corresponds to 320 ASA; if it says 250 GOST (post-1981), that’s 250 ASA, so with an older camera or light meter, you’re not overexposing but underexposing. Actually, you can tell which system is meant by the scales: the old ones are 65 and 130 GOST, the newer ones are 64 and 125 GOST. This falls within a range where you can still correct for it with the development time; nothing is ever exactly right with cameras and film, and if you don’t develop the film yourself, you won’t notice it. The fact is that in the early 1980s, new films came out that had a fine grain and were labelled ‘FN’ instead of ‘FOTO’, and were officially adapted to ASA; how long it took for everything to really change with cameras and film is, of course, another question. Colour films, good question – I didn’t have many. I think the ones from the end of the USSR were labelled Swema DS-4 ‘40 GOST 17 DIN 40ASA’ and the older ones ‘32 GOST 17 DIN 40ASA’. What I had was colour negative film for daylight; it was actually so poor that there had to be separate negative films for daylight and incandescent light. The method used at the Ukrainian film factory is also rather like this: make the film emulsion, pour it, and experiment with development times to find the right speed; as a result, every batch is different. The GOST standard printed on the box isn’t worth much for either the camera or the film. I’m Ukrainian; films from the GDR and Czechoslovakia were also available, but rarely, because they were really good – sometimes Forte (just about acceptable) or Azomures (partly barely usable). ORWO had NP 15, NP 20 and NP 27; in the GDR, NP 20 was listed as 65 GOST, I don’t know about the others. I also once had NC 19, 64 GOST (?), but only got one roll of film from it. ORWO hadn’t quite adapted to the change yet, so they continued to print some NP 20 rolls according to the old system and some NC 19 rolls according to the new one. American film, of course, couldn’t be bought in shops that easily, but press people sometimes had some. I simply mean that, for example, Swema FN 125, just like Kodak Plus-X, officially has 125 ASA; well, Swema practically always has higher speed than Kodak, hence the comparison with ‘amerikanskij fotoplenka’. Oleksander