[BigMackCam]

I have a question that I think I know the answer to, but I'd like to check with you good folks that have more experience

I've read quite a lot about many films having a box speed that's arguably higher than the "real" speed... for instance, ISO 400 films that are allegedly closer to 320, 250 or even 200 in reality. In several articles and posts I've read, the suggestion is to shoot at "real" speed rather than the box speed... but no-one ever mentions if the development times change. I assume they don't. So, if I shoot Fomapan 400 at, say, ISO 250 - 320 (as many would suggest) and therefore technically over-exposing it with reference to box speed, do I keep the development as per the Massive Dev Chart timings for ISO 400?

Thanks in advance

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Last edited by BigMackCam; 01-02-2022 at 01:20 PM.

[vonBaloney]

When shooting negative film (back in the days when I shot film), I always set the speed one stop less than the box speed. This wasn't to compensate for exaggerated claims on the box, but to over-expose slightly to ensure a nice dense negative. Generally a bit of "over-exposure" on negative film is not a problem whatsoever, whereas underexposed thin negatives are often unrecoverable. (Positive slide film is a different story -- you have to be much more careful.) I would develop normally as per the recommendations for that film (unless I knew I needed to push for some reason). Certainly I wouldn't shorten dev times as that would be counter to the whole point of "over-exposing" in the first place. i.e. I don't think of it as over-exposing at all, and it is nice to know that you do have a little leeway in lower light situations. And If I thought the speed on the box was actually too high -- it should be set according to strict standards -- then I'd over-expose even more.

[StiffLegged]

Mmmmm. I should like to know why manufacturers print the box speed if users actually know better? Or are camera meters actually spot on? Maybe many of us needed more practice with exposing accurately? (yes we did) My best results were from careful metering, attention to temperature and timing when developing and being very fussy when printing. Can’t say I found reasons to disbelieve the box speed with the films used, nor the recommended development times.

[BigMackCam]

Mmmmm. I should like to know why manufacturers print the box speed if users actually know better?

I suspect your question, also the follow-up regarding metering accuracy, are a tad facetious... Fair enough, and yet, here's an example of the kind of thing I'm talking about:

https://emulsive.org/articles/film-notes-current-high-speed-films-ilford-del...andrew-blowers

One quote from that article states:

ILFORD Delta 3200 Professional and Kodak T-MAX P3200 are natively ISO 1000 and ISO 800 respectively, and designed to be shot in a variety of ways — these films can be whatever the photographer chooses to make of them. The Delta and T-MAX ranges fill kind of the same niche on paper; they are both modern emulsions with low speed-to-grain ratios, implying clean, sharp results relative to their high ISO rating.

Now, that could be complete balderdash. Sadly, in these days of the internet it's ever more difficult to sort the wheat from the chaff. Still, you can appreciate the reason for my interest?

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Last edited by BigMackCam; 01-02-2022 at 03:38 PM.

[StiffLegged]

Hmm. Well, I have no experience of the t-grain emulsions, I used medium and low-speed emulsions and the subjects and shooting styles in the article - not to mention the methods of determining exposure - are so different to my own film days that it’s difficult to draw direct comparisons. Pass the salt.

[vonBaloney]

Yes, speed of a film is also to be considered "as stated" when developed according to manufacturer specifications -- they go together. But you can get creative for how you actually use them and develop them. After all this isn't digital, it's analog. It's a chemistry problem, not math, and you can approach it somewhat like a chef preparing food.

[pres589]

There are some experts in this sort of thing here on the forum that you should really listen to, and not me, so keep that in mind when you read the following;

I think it depends. Different developers will increase or decrease effective speed. Development schemes will also do the same. The box speed is a nominal speed given with a specific developer in mind. I'm not sure what developer Foma references when they say their 400 Action is ISO 400; I think it's Microdol but I may be mistaken. In any case, there's real tools to test this sort of thing, and I don't have them, and I'm kind of sloppy about all this.


Foma 400 is, I think, a fun film to shoot with. When you get comfortable with a specific film stock and developer you can find what best works for you and delivers the results you like. If you were shooting Foma 400 and developing with D-76 you might find that rating it at EI 250 gets you results you like more than 400, as an example (probably pretty close to accurate). I would still use the developing times for the box speed for each given developer that you try it with, meaning, shoot it at 250, develop it like it's 400 as Foma recommends.

[UncleVanya]

In the film era I shot mainly slides. I shot slightly underexposed say iso 80 on iso 64 Kodachrome from time to time. But generally I kept to the box speeds.

With negative film the exposure latitude was so large exact ASA wasn’t an issue that came up often.

[stevebrot]

I always evaluate effective EI* when when shooting a new B&W emulsion or developer. Often box speed is fine; sometimes, not.


Steve

* Lacking a densitometer, I use a standard subject that challenges high and low values for detail.

[Cerebum]

I think box speed is a safe place to get to know a film, however, in the YouTube video below, the user is testing Fomapan 100 on a Voigtlander Vito B. In the film he shows that the film data clearly states you can push and pull the film and still process it at box, which he does to good effect. Its quite a revelation. I have wished I had one stop more on a few occasions.

Youtu.be

Youtu.be

Yeah it is an obscure video, good though. My interest was in the camera as the Vito B is very similar to the pending Vitomatic ii that I am currently getting very excited about

[BigMackCam]

I think box speed is a safe place to get to know a film, however, in the YouTube video below, the user is testing Fomapan 100 on a Voigtlander Vito B. In the film he shows that the film data clearly states you can push and pull the film and still process it at box, which he does to good effect. Its quite a revelation. I have wished I had one stop more on a few occasions.

The pushing / pulling aspect also interests me, though I'm avoiding it until I have more experience. But it's a bit different than the issue I'm referring to here... at least, I think it is. At present, I'm shooting at box speed - no ifs or buts... BUT () I've read an awful lot of articles and posts that seem to suggest certain films - especially, it would seem, the faster emulsions - are box-rated higher than the native speed. At face value, I tend to agree with @StiffLegged that the manufacturers have rated the film at what they consider to be the optimal speed, and with accurate metering (which is a whole subject in itself), that's the default speed we should use... but the "no smoke without fire" idiom has me wondering if there's something to all the content I've read suggesting lower native speeds. Then again, it could just be those folks are poorly describing a preference for over-exposing slightly, which seems to be a very common thing - as @vonBaloney mentions above...

[3by2]

I've never heard this, that the native seed is not as advertised, what I have heard is that some films benefit from a push or a pull. I used to commonly do this with vericolor for portraits in strong light. What I can't remember is what I used to commonly do, only that I commonly did it, well, it was 30 odd years ago. Vericolor became something else which they still make, probably with similar characteristics.

[Cerebum]

The pushing / pulling aspect also interests me, though I'm avoiding it until I have more experience. But it's a bit different than the issue I'm referring to here... at least, I think it is. At present, I'm shooting at box speed - no ifs or buts... BUT () I've read an awful lot of articles and posts that seem to suggest certain films - especially, it would seem, the faster emulsions - are box-rated higher than the native speed. At face value, I tend to agree with @StiffLegged that the manufacturers have rated the film at what they consider to be the optimal speed, and with accurate metering (which is a whole subject in itself), that's the default speed we should use... but the "no smoke without fire" idiom has me wondering if there's something to all the content I've read suggesting lower native speeds. Then again, it could just be those folks are poorly describing a preference for over-exposing slightly, which seems to be a very common thing - as @vonBaloney mentions above...

Haha, yeah I forgot to tie it in what I meant to say was box speed was suck it and see but the guy in the video was pushing but still processing at box. I have seen a few references to film having an actual speed (discovered through use) that differs from box. Thinking about it, maybe they are suggesting we shoot and process at what has been discovered to be the true optimum. I don't know about you Mike, but I am still in the "OH MY GOD, TOO MANY VARIABLES!!!" Phase of my film journey! The rabbit hole goes down a looooooong way


But then, the cameras are beautiful.....

[BigMackCam]

I don't know about you Mike, but I am still in the "OH MY GOD, TOO MANY VARIABLES!!!" Phase of my film journey! The rabbit hole goes down a looooooong way

Yes, I'm definitely in that phase I get a bit frustrated at times with how little I know regarding film, and how slowly I'm learning... but then, I look back and see I didn't buy my Agfa Isola II until September last year... then spent a few weeks putting together - and learning to use - my film digitising setup. I didn't shoot and develop my first film until mid-to-late November... and I've only just this morning finished shooting my second - the 35mm roll I started just before Christmas (my infamous "Angry Turkish Barber" shoot ). I'm still at the "information overload" stage, but with the help of members here and a lot of reading, I definitely know a good deal more than I did last September, and I'm more confident about developing my second film (of course, saying so will be the kiss of death - watch me screw it up now )...

But then, the cameras are beautiful.....

Aren't they just? The design, materials and finish are to die for. Even the little Olympus Trip 35 that I was shooting this morning just looks and feels like real quality. So solid... all metal... a pleasure to shoot

[Cerebum]

Yes, I'm definitely in that phase I get a bit frustrated at times with how little I know regarding film, and how slowly I'm learning... but then, I look back and see I didn't buy my Agfa Isola II until September last year... then spent a few weeks putting together - and learning to use - my film digitising setup. I didn't shoot and develop my first film until mid-to-late November... and I've only just this morning finished shooting my second - the 35mm roll I started just before Christmas (my infamous "Angry Turkish Barber" shoot ). I'm still at the "information overload" stage, but with the help of members here and a lot of reading, I definitely know a good deal more than I did last September, and I'm more confident about developing my second film (of course, saying so will be the kiss of death - watch me screw it up now )...



Aren't they just? The design, materials and finish are to die for. Even the little Olympus Trip 35 that I was shooting this morning just looks and feels like real quality. So solid... all metal... a pleasure to shoot

My first film in 40 years was some Foma in a loaned 30s Leica iii back in June. Since then I have fished out a Spotmatic, bought for the Takumars, light sealed and re-skinned it and that works beautifully. I bought an MX that has an intermittent fault and is off for a cla this week. When it works though it gives you such a great feeling when you use it. I have a couple of camera and lens repair projects for this year, all basic stuff but, like the spotty, it is so satisfying when it works. Films wise, I have shot quite a few in six months, my favourites being some Rollei rpx 400 and some doublefilm bubblegum. I have done zero processing and scanning but home processing and scanning are the only way I will be able to continue with film, it is just too expensive otherwise, so threads like this and all the others you have started will be invaluable. I can't wait for the voigtlander Vitomatic ii to arrive, that looks superbly engineered. As for restoring film cameras, you should try it it is very satisfying. I consulted my personal oracle re the original question here but he is in Keswick so doing more important stuff, in the meanwhile, get a load of this beauty! I still can't believe it was just £25