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1. To drive you crazy! [It is half the speed of Tri-X 320!]

Why do olives come packed in salt water and sardines come packed in olive oil?

Steve
Why are the labels on Cranberries upside down according to how the can is opened? I have asked many people that and no grocer knows the answer.

Maybe it goes with ASA 64. I use ASA because that film is long gone. What's the most unusual film speed listed by a manufacturer?

I love those King Oscar ones. http://www.kingoscar.com/company

My step grandfather was Norwegian, we fished and hunted and ate King Oscar Sardines, but I've told that story before...

BTW: where is Ole these days?

2. 160 Asa as we think of it today may be strange for us, but it is 23DIN.
Is 23 more or less logical than 21DIN (that is 100Asa) or 27DIN (400Asa)?

3. To make film faster, the sensitivity has to increase exponentially, i.e. one step difference means doubling the sensitivity. In reverse, it decreases logarithmically. A similar thing happens with music. If you look at the neck of a guitar, the frets aren't spaced evenly, they get further apart the further from the body you go.
100-200-400-800-1600 are the major steps, but each step has half and third steps between it and the next one. Because the scale is exponential, a third of a step isn't 0.33, and changes throughout the step. The difference between 100 and 125 is the same as between (125 and 160) and (160 and 200) and (400 and 500) and (5000 and 6400). These aren't exact figures because the actual figures are horrendous irrational numbers, but 160 is a lot easier to remember than some awful and negligibly different surd.

4. I've always wondered this too...

And also, I've never (that I can recall) seen ISO 200 120 rolls. Do they exist?

EDIT: Well explained Mattmoy, makes much more sense to me now!

5. Originally Posted by Mike1234
Wouldn't 141 speed be closer to the middle of 100 and 200?
It would be the exact middle between 100 and 200. But ISO speeds typically go in 1/3 stops rather than 1/2 stops. So you are more likely going to see ISO125 or ISO160 than ISO141.

Originally Posted by Chris Nielsen
If clocks go clockwise because of the sundial and sundials run anticlockwise in the southern hemisphere, then clocks down here should run anticlockwise as well, shouldn't they?
Maybe if clocks were invented in the Southern Hemisphere.

6. Originally Posted by Blacknoise
I've always wondered this too...

And also, I've never (that I can recall) seen ISO 200 120 rolls. Do they exist?

EDIT: Well explained Mattmoy, makes much more sense to me now!

7. Maybe 160 is a nicer number than 200.
Since 160 looks more like 100 than 200, it gives a different thinking about the film; Less grain, more sharpness...

Just like when prices are 9.95/9.99 instead of 10.

8. To remind you to rate it at EI-125.

9. Sixty years ago color films used to be ASA 12. Just be glad you have 160.

10. The Kodak portrait color negative films have slowly gained speed through the years. Ektacolor Professional S (C-22) and Vericolor S (C-41) were ASA 100. Vericolor II Professional S was ASA 125. Vericolor III was 160, as is Portra 160NC (of course). So it gained speed a third-stop at a time over the last 35 years.

Of course, with Portra, they also added 400 speed films, and later an 800 speed.

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