Film Test: Svema 42L -- Thin Base For 72 Exposure Rolls

[ic-racer]

I just got some Svema thin based 42L film for testing.

Firtst off, 72 exposures of the film does indeed fit in a 35mm cassette. In fact I rolled 80 frames total into this cassette.

 

[ic-racer]

The Svema 42L was compared to Ilford HP5 35mm film.

Both films were exposed on the same white-light senstometer one right after the other. Then immediately processed together in the same tank.

 

[ic-racer]

First impression is that Svema 42L is medium speed and quite contrasty.

Just looking at this it appears the Svema (left side) is about 3 steps (1.5 stops) slower than HP5. I'm guessing, after plotting, the speed will be about 125 if HP5 is called 400.

 

[Romanko]

It would be interesting to see Svema 42L vs. Agfa Aviphot comparison.

 

[ic-racer]

Even though, based on ISO standards, this film is only medium speed, the negatives at EI 800 appear dense.

My experience with short-scale films like this is to use an EI based on a mid tone, rather than low value (per ISO) or shoulder value (per reversal). I have seen films in which decreasing development does not change the horizontal position of the shoulder. That is to say, irrespective of development, it is always a short scale film.

More testing on this film will show how it actually behaves, but my impression is an EI of 1000 might actually give the best images for many subjects; the film inherently won't have good shadow detail without the highlights going off the shoulder.

More to follow...

 

[ic-racer]

After plotting and comparig relative speeds, if the HP5 is defined as 400, the Svema 42L tests as 150 based on ASA/ISO criteria.

More testing is in order to tame to contrast.

 

[Romanko]

Are you developing in D-76? What do the characteristic curves look like?

 

[ic-racer]

Are you developing in D-76? What do the characteristic curves look like?

These were rotary processed with T-max developer 1:4 at 24c for 5 min. I will post a screen shot of the curve. It is steep with not much toe or shoulder.

 

[ic-racer]

The speed rating of the film (1000 or so) is based on ISO ISO 7829:1986 (lower diagram).

Similar to ISO 6:1993 and ASA the most people know, the speed rating for aerial films is based on a speed point of 0.3 log d with a slope/gamma/contrast of 1.0 (or even higher).

So, testing the film with the ISO 6:1993/ASA (top diagram) criteria is a little challenging as the gamma needs to come down to 0.8 from over 1.