"200ISO, but I wouldn't use it past 125" What does this mean?

[beala]

So I recently bought a bulk roll of 35mm BW Fomapan 200, and have been doing some research on it. Several sites I've come across say things like "This is rated at 200, but I wouldn't use it past 125." What exactly does this mean? Does it mean I set my camera to 125 ISO, and develop normally. Or shoot at 200ISO and pull process to 125? Or something else?

Thanks a lot!

 

[David A. Goldfarb]

This means you should do some testing and see what speed gives you enough shadow detail on the negative and what development time gives you highlights that print easily using the method you like to use.

What they are saying is that for them, setting their meter at 125 and developing normally (whatever "normally" is) gives good results.

 

[Paul Cocklin]

Presumably it means that they don't believe the box speed is the correct speed for the film, and believe it to be much slower, somewhere around an ISO 100 or 125. Of course, as I've had explained to me numerous times until I finally got it, determining film speed is a very personal thing that depends upon your developer, developing time/temp., etc. Case in point, while most films seem to be considered somewhat slower than the box speed, my testing gives me an ISO of 160 with Ilford Delta100.

If I had to offer a suggestion (and lord knows I'm not the best person to do it) I'd say expose a film speed test roll at 125. Since it's bulk, you can load a canister with 15 shots or so to avoid wasting film. If you're wondering how to shoot a film speed test, do a search here on APUG, I'm sure there's dozens of threads about it.

Hope this helps!
Paul

 

[Paul Cocklin]

Beat me to it, David.

 

[pentaxuser]

I think this is a reference to the belief held by a number of photographers that unless this is developed in a speed increasing developer it really is a ISO125 film and Foma have used some licence in declaring it a ISO 200 film.

I can't speak from experience as I have never used it

pentaxuser

 

[beala]

Thanks a lot guys! You're all incredibly helpful, as usual!

 

[pentaxuser]

Eureka! I have just come across a reference by Roger Hicks, late of this parish, on his Roger and Frances site to Fomapan 200 where he categorically states that this film isn't ISO 200 except in a speed increasing developer like Ilford /Harman's Microphen. I'd take that as pretty good evidence.

pentaxuser

 

[Sirius Glass]

Roger Hicks was a great contributor here. Unfortunately he no longer graces our door.

Steve

 

[Tim Gray]

I'd also like to say it depends on your metering technique. Meters usually are NOT set to give a reading corresponding to 18% gray, contrary to popular belief.

 

[Venchka]

Roger agrees

Eureka! I have just come across a reference by Roger Hicks, late of this parish, on his Roger and Frances site to Fomapan 200 where he categorically states that this film isn't ISO 200 except in a speed increasing developer like Ilford /Harman's Microphen. I'd take that as pretty good evidence.

pentaxuser

Nice to hear that Roger agrees with me.

My regimen: 4x5 Arista-EDU.Ultra 200 at E.I. 100, Xtol 1:3, 10 minutes, continuous agitation. I am cutting back a bit on the time. Too early to say for sure, but my last sheet at 8 minutes looked very nice.

 

[jim appleyard]

Here's Roger & Francis' page on ISO: http://www.rogerandfrances.com/photoschool/ps iso speeds.html

Check out the other stuff there as well; lots of good info.

...and another article:http://www.fredparker.com/ultexp1.htm

 

[2F/2F]

It means that the people posting on the Internet are not getting the density that they want in the darker areas of the composition with the equipment they are using, the way they meter, the way they develop, the way they print, etc.

As you can see, it is quite subjective and variable person to person.

It could just be a very contrasty film. Often people think that very contrasty films need to be rated slower than the ISO in order to fit their idea of what a film should capture.

Others, like me, say, "The film is just contrasty and does not easily capture detail in the darker areas. If that doesn't suit the picture I want, then I will tweak things to change the contrast."

The way I prefer to think about it, a film has a certain amount of contrast at any given rating and development, and I always use box speed unless I want to apply a blanket EC to the shot. If the luminance range of the composition exceeds that of the film, then I alter exposure and development to suit. I learn how to do this through experience and/or testing.

What I am saying is that the film may just be a very contrasty film by most people's standards when rated and developed at EI 200, and also that most people might get flat negs when following the manufacturer's recommended times. Instead of manually applying exposure and development tweaks to change this, many people simply apply a blanket EC to the film by down rating it, and read directly off of the meter instead of manually changing exposure from the meter reading. Doing so is effectively saying, "100% of the time, this film drops too much low-toned detail for me to get the prints I want."

It's really the same thing. I just generally prefer to learn the characteristics of the film, both straight and tweaked, and manually apply manipulation instead of building it into my meter reading.

In short, do your own testing to determine the contrast of the stuff for the way you shoot, develop, and print it.

...and YES, it is very likely that manufacturer's published ISO and developing times are just plain wrong for what you want.

...also, YES, downrate the film if you are unsure of yourself (i.e. have not tested yet). With a negative, it is generally better to be over than under.

 

[PhotoJim]

There are few films that I rate at other than box speed, but when I shoot Foma 200 I rate it at EI 100.

 

[clayne]

Here's Roger & Francis' page on ISO: http://www.rogerandfrances.com/photoschool/ps iso speeds.html

Check out the other stuff there as well; lots of good info.

...and another article:http://www.fredparker.com/ultexp1.htm

Directly on that page:

"Many photographers find a gamma of 0.62 or so perfectly satisfactory, but many don't. A lot depends on subject matter, lighting conditions, lens contrast, and enlarger type. Some prefer a higher contrast, typically up to about 0.70. Rather more prefer a lower gamma, 0.56 or lower. Understandably, those who prefer the higher gamma get more speed than those who prefer the lower gamma."

"This sometimes leads those who prefer a lower gamma to say that films are never 'really' as fast as the manufacturers say they are. This is nonsense. The vast majority of films are very close to their ISO speeds under ISO conditions. Some are even above it, though rarely more than 1/3 stop. It is perfectly legitimate to develop to a lower contrast, and you should do so if that gives you the results you like, but as soon as you depart from ISO conditions, you cannot make judgements on ISO speeds. At this point you are dealing with exposure indices (EIs) rather than ISO speeds."

 

[gainer]

Nobody mentions the necessity of knowing the shutter and f-stop accuracy of the camera. A shutter speed that measure 1/100 second when set at 1/60 or an f-stop that measures f/8 when set at f/6.3, or a combination of shutter and f-stop inaccuracies could convince one that the film is rated too fast. Take such recommendations with a grain of silver chloride until you test them. Errors may be in the recommender's equipment or your own or both. A few test shots with bracketted exposure settings + or - 1/2 exposure unit should help settle the matter.

 

[clayne]

Nobody mentions the necessity of knowing the shutter and f-stop accuracy of the camera. A shutter speed that measure 1/100 second when set at 1/60 or an f-stop that measures f/8 when set at f/6.3, or a combination of shutter and f-stop inaccuracies could convince one that the film is rated too fast. Take such recommendations with a grain of silver chloride until you test them. Errors may be in the recommender's equipment or your own or both. A few test shots with bracketted exposure settings + or - 1/2 exposure unit should help settle the matter.

Of course that won't account for calibrated equipment which would be the only thing that could give us an absolute ISO rating, don't you agree?

 

[2F/2F]

Directly on that page:

"Many photographers find a gamma of 0.62 or so perfectly satisfactory, but many don't. A lot depends on subject matter, lighting conditions, lens contrast, and enlarger type. Some prefer a higher contrast, typically up to about 0.70. Rather more prefer a lower gamma, 0.56 or lower. Understandably, those who prefer the higher gamma get more speed than those who prefer the lower gamma."

"This sometimes leads those who prefer a lower gamma to say that films are never 'really' as fast as the manufacturers say they are. This is nonsense. The vast majority of films are very close to their ISO speeds under ISO conditions. Some are even above it, though rarely more than 1/3 stop. It is perfectly legitimate to develop to a lower contrast, and you should do so if that gives you the results you like, but as soon as you depart from ISO conditions, you cannot make judgements on ISO speeds. At this point you are dealing with exposure indices (EIs) rather than ISO speeds."

Exactly what I was tryin' ta say when I said:

It means that the people posting on the Internet are not getting the density that they want in the darker areas of the composition with the equipment they are using, the way they meter, the way they develop, the way they print, etc.

As you can see, it is quite subjective and variable person to person.

It could just be a very contrasty film. Often people think that very contrasty films need to be rated slower than the ISO in order to fit their idea of what a film should capture.

Others, like me, say, "The film is just contrasty and does not easily capture detail in the darker areas. If that doesn't suit the picture I want, then I will tweak things to change the contrast."

Not a single one of us in the "real world" is using ISO procedures, materials, and equipment that were used to test the film. Therefore to say that "the ISO is wrong" is just not true without qualifying the statement further. "My working EI, established using my own methods of working EI establishment, is different than the ISO speed", or "The ISO rating does not work to get the pictures I want" are more like it.

 

[clayne]

Exactly what I was tryin' ta say!

That's why I highlighted it, 2F.

I'm also a type that utilizes contrast in different ways, depending on scene, subject and feel, rather than endlessly hunting for elusive "shadow detail" no matter what the emphasis.

 

[gainer]

Of course that won't account for calibrated equipment which would be the only thing that could give us an absolute ISO rating, don't you agree?

Yes, I agree. There remains the question of what the tester knows about the ISO method of testing. What I'm looking for is something more specific than what we usually get about how the stated speed was calculated.

 

[BradS]

Eureka! I have just come across a reference by Roger Hicks .... categorically states that this film isn't ISO 200 except in a speed increasing developer like Ilford /Harman's Microphen. I'd take that as pretty good evidence.

pentaxuser

Foma's own data sheet says as much. Their own speed testing graphs clearly show the speed of this film makes it to 160 with extraordinary contrast when developed in Microphen. I don't know where they get off labeling it ISO 200

 

[eddym]

I'm also a type that utilizes contrast in different ways, depending on scene, subject and feel, rather than endlessly hunting for elusive "shadow detail" no matter what the emphasis.

Me too. Sometimes, in the real world, the shadows are interesting... and sometimes they're not. Some of my best pictures have deep, dark shadows with no detail. So shoot me.

 

[removed account4]

So I recently bought a bulk roll of 35mm BW Fomapan 200, and have been doing some research on it. Several sites I've come across say things like "This is rated at 200, but I wouldn't use it past 125." What exactly does this mean? Does it mean I set my camera to 125 ISO, and develop normally. Or shoot at 200ISO and pull process to 125? Or something else?

Thanks a lot!

hi beala

when film companies label their films with a certain iso/asa
it is done in a lab in strictly controlled conditions ...
when we use their films the way we use them,
we are straying from the environment/s that declared it was iso200 ...

i like fomapan 200 ... it's great stuff ...
since you are bulk loading it, why not clip off a 12exposure roll
and bracket 3 or 4 exposures - 200, 400, 100 and process as you normally do.
this will determine what iso will work best for you ....

have fun
john

 

[rjr]

"This sometimes leads those who prefer a lower gamma to say that films are never 'really' as fast as the manufacturers say they are. This is nonsense. The vast majority of films are very close to their ISO speeds under ISO conditions.

The problem with the ISO in this regard is the contrast index at which the norm speed is determined. I don´t have the ISO at hand at hand -but I have it stacked somewhere and read-, but IIRC the speed is rated at a CI of 0,80; as all of us know, a lower CI gives us a lower speed, a higher CI results in higher speed.

Point eight is way too steep for our photographic processes, but it´s the norm. Deal with it.

 

[Ian Grant]

The problem with the ISO in this regard is the contrast index at which the norm speed is determined. I don´t have the ISO at hand at hand -but I have it stacked somewhere and read-, but IIRC the speed is rated at a CI of 0,80; as all of us know, a lower CI gives us a lower speed, a higher CI results in higher speed.

Point eight is way too steep for our photographic processes, but it´s the norm. Deal with it.

Not strictly true, the problem is that the ISO test for film speed can be done one of two ways.

The first is the old ASA/BS system, both identical for B&W films, which measures the films thresh-hold speed and the second is the German DIN standard which is very much more practical, somewhere back in the UK I have the full details of both test methods.

Kodak use the ASA method this is why bmany people downrate Tmax, Tri-X etc to get a full tonal range.

Agfa used the DIN system which is why their films almost always gave a true box speed. ISO speed includes ASA & DIN, in Agfa's case the 100/21° ISO of APX100 is just a conversion from the 21°DIN to 100ASA.

For all practical purposes I used to use Tmax100 @50 EI, and APX100 @100 same dev times etc and got virtually identical tonality etc.

Fomapan 200 & 100 need approx 2/3rds the dev times of all other films or they build up extreme conrast this will impact on the ASA testing done for film speed.

Ilford now quote EI's and dev times based on practical tests, so their approach is more akin to the DIN system.

If all manufacturers actually used the DIN method of testing there would be fewer anomolies, and Kodak Tmax100 would have been known as Tmax50 - ISO50/18°

Ian

 

[removed account4]

"why is it called tmax 3200? ...
because it sounds so much better than tmax1600"