Tri-X 400 @ 200... Why?

[film_guy]

Isn't rating the film at 320 instead of box speed plus the +1/3 to +1/2 in exposure going to help, instead of just +1/3 to +1/2 at box speed for any 400 film?

 

[reub2000]

Exposure is exposure. It doesn't matter how you arrived at your particular aperture and shutter combination.

 

[Roger Hicks]

Roger: I'm not sure what you mean by "over-exposure". Do you mean more exposure than "box speed", i.e., one's personal EI rating, or over-exposure from one's tested EI? The reason I ask is that, like many others, I shoot Tri-X @ 200/250, which I arrived at through the standard "Zone I threshold" test. My development times are then based on the time/temp/agitation sequence to get a Zone VIII exposure to print to Zone VIII at the same print exposure time/conditions that give a Zone I print from the Zone I test exposure. Of course, I also check to make sure Zone III exposures are correct.

When I do this, I find grain, especially, is somewhat better than at box speed ... due to reduced time I suspect.

Basically, more exposure = more grain and less sharpness. Under-expose, and you'll get even finer grain and even better sharpness with a test target, but the tonality and shadow detail go to hell.

Underdevelopment = less grain and more sharpness, too, so if you under-develop you'll get some of the lost grain & sharpness back.

The sort of Zone testing you describe is ideal for establishing a personal EI, and should be undertaiken by anyone with the inclination and stomach for it, but has little or nothing to do with 'true film speed' in the sense of results that are replicable by others using different equipment, or indeed with toe speed which is the basis of definition of ISO speeds.

Sorry, it's just one of those things that drives me up the wall when people say "The real speed is ISO...", because it almost never is. The real speed is almost invariably the ISO speed in the manufacturer's stated developer (and can rise or fall in other developers). The EI that many people are happiest with is commonly 1/3 to 2/3 stops lower than the true ISO -- as I said myself, I'm one of 'em -- but this is in no sense a 'true' speed.

Afterthought: reflecting on this, I realized that the 'Sorry' could be misread: it's often one of those things people say when they mean 'I'm not sorry at all...' What I meant was, "I apologize for appearing testy on the subject, but..."

Cheers,

R.

 

[Roger Hicks]

If I get something for free, I don't complain about some ads. Anyway, Roger has a lot of other good stuff on his site. Good to get a chance and reminder to look at the rest.

Dear Ralph,

Thanks for the support and kind words. The thing is, I genuinely don't see how to link directly, because all it says at the top in the address bar when I log on to the site is 'www.rogerandfrances.com'.

Also, as you say, it's free: I seldom mention paid modules, and if someone doesn't want to go to the comparatively modest effort of going through the home page, etc., to get to the free information, they don't have to. It's not as if the free information is any harder to get to than the paid. (In fact it's easier -- you don't have to pay).

Cheers,

R.

 

[thefizz]

I tested 120 TriX as per Fred Picker and got an EI of 500. Does that mean my TriX is grainier than those who got 200/250 (considering we use same dev)even though I tested correctly.

Peter

 

[pgomena]

Not necessarily, Peter. Much depends on metering and developer.

In my earlier post in this thread, I said I found EI200 gave me better shadow detail with Tri-X and D-76 or HC-110. This was for incident metering in "average" daylight conditions based on the sunlit exposure, not shadow.

When I tested the same film using PMK Pyro and BZTS methods, I got EI500. This is using an incident exposure based on an exposure set at 1 stop below the average shadow reading. Didn't seem to affect grain much in 35mm compared with the other methods and developer.

Some developers are noted for producing less shadow detail than others at box speed. Some developers produce better film speed, shadow contrast and detail plus contrast control when used semi-stand. There are a lot of variables at work here.

I used Fred Picker's methods for years, and attended one of his workshops in 1980. What impressed me most about his methods was how well he had Tri-X and HC-110 tuned in for his personal use. He also had the original Zone VI Brilliant paper manufactured to match Tri-X tonality beautifully. He matched the response of the Zone VI meter to Tri-X as well. His EI for Tri-X sheet film was 160. Mine tested out to be the same. Probably more coincidence than hard fact. His pictures looked much better than mine, though . . .

Don't make too much of the numbers. Test the materials and see how it works for you in your darkroom.

Peter Gomena

P.S. -- One of Ted Orland's Photographic Truths is that "No two meters will ever read the same." No one uses them in exactly the same way either.

 

[dslater]

Sorry, it's just one of those things that drives me up the wall when people say "The real speed is ISO...", because it almost never is. The real speed is almost invariably the ISO speed in the manufacturer's stated developer (and can rise or fall in other developers). The EI that many people are happiest with is commonly 1/3 to 2/3 stops lower than the true ISO -- as I said myself, I'm one of 'em -- but this is in no sense a 'true' speed.

R.

The problem with the manufacturer's ISO rating is that it is arrived at with an unrealistically high contrast. In general if you follow the manufacturers recommendations for exposure and development, what you end up with is a negative that is under-exposed and over-developed.

 

[Thomas Bertilsson]

I rate Tri-X at 200 if I want the shadow detail, but it also has another benefit that I haven't seen mentioned yet - less dust problems. When you have to print through dense negatives, I have found that dust doesn't affect the print as much as with a normal to thin negative.
Other times I like a really contrasty look with deep, fat, rich blacks even without detail, and then I shoot Tri-X at 400 or even 800 and develop longer. I love the flexibility the film gives me. When I give less exposure I usually employ developers like Diafine to make up for some of it. Normal developer for me is Pyrocat-HD which looks nice at 200 and 400 exposure index.

- Thom

 

[Roger Hicks]

The problem with the manufacturer's ISO rating is that it is arrived at with an unrealistically high contrast. In general if you follow the manufacturers recommendations for exposure and development, what you end up with is a negative that is under-exposed and over-developed.

In a word: no. It may not suit you and your subjects and equipment. It certainly didn't suit the Japanese representatives on the ISO standards committee, who lobbied for a drop equivalent to a C.I. of around 0.56. The current standard equates to about 0.615.

When the matter was discussed at the committee -- one of my friends was on it at the time -- they accepted that this was because Japan is a long way south of Rochester NY (and even further south of the original Rochester) and this affects 'typical' subject brightness ranges.

There are also certain assumptions in the ISO standard about flare levels (among other things) which may not suit your equipment. They suit a lot of mine. I could equally well say that any contrast less than the current standard would be unrealistically low.

Furthermore, thanks to the ingenious way that the ISO contrast criterion is constructed -- the Delta X criterion, as described in Stephen Benskin's brilliant paper of that name -- development time makes less difference to ISO speed than might be expected, except in the case of gross underdevelopment.

Whether or not you, or I, or the Japanese members, accept the ISO standard, at least it's a standard, not a personal EI, and anyone who talks of 'true speed' being lower is either failing to define 'true speed' at all or is using a personal definition unrelated to a standard true speed.

Finally, as an Ilford representative once said to me, "Why would we tell people to use the wrong film speeds and development times? Because we want to stop them getting the best possible results from our films? Or perhaps out of sheer spite?"

Cheers,

R.

 

[RalphLambrecht]

In a word: no. It may not suit you and your subjects and equipment. It certainly didn't suit the Japanese representatives on the ISO standards committee, who lobbied for a drop equivalent to a C.I. of around 0.56. The current standard equates to about 0.615.

When the matter was discussed at the committee -- one of my friends was on it at the time -- they accepted that this was because Japan is a long way south of Rochester NY (and even further south of the original Rochester) and this affects 'typical' subject brightness ranges.

There are also certain assumptions in the ISO standard about flare levels (among other things) which may not suit your equipment. They suit a lot of mine. I could equally well say that any contrast less than the current standard would be unrealistically low.

Furthermore, thanks to the ingenious way that the ISO contrast criterion is constructed -- the Delta X criterion, as described in Stephen Benskin's brilliant paper of that name -- development time makes less difference to ISO speed than might be expected, except in the case of gross underdevelopment.

Whether or not you, or I, or the Japanese members, accept the ISO standard, at least it's a standard, not a personal EI, and anyone who talks of 'true speed' being lower is either failing to define 'true speed' at all or is using a personal definition unrelated to a standard true speed.

Finally, as an Ilford representative once said to me, "Why would we tell people to use the wrong film speeds and development times? Because we want to stop them getting the best possible results from our films? Or perhaps out of sheer spite?"

Cheers,

R.

I like the standard, because it allows us to compare. However, my needs, equipment and subject matter must be much closer to this Japanese fellow's, because 0.57 (1.2 negative density range divided by 2.1 subject brightness range or 7 zones) is what I'm shooting for (and I don't use a condensor enlarger either). IMHO, 0.615 is just too high for pictorial pphotography.

In any event, what I don't quite understand is, that Ilford claims not to use the ISO sttandard procedure to arrive at their film speeds but call it ISO on their film boxes. How does that work?

 

[Ole]

http://www.rogerandfrances.com/photoschool/ps iso speeds.html

Cheers

Just FYI: I right-clicked on the link, and selected "Copy link address". Then I pasted that in here.

 

[Roger Hicks]

Just FYI: I right-clicked on the link, and selected "Copy link address". Then I pasted that in here.

Ah... the mysteries of right clicks. Maybe I won't learn after all...

But thanks anyway.

Cheers,

R.

 

[Roger Hicks]

I like the standard, because it allows us to compare. However, my needs, equipment and subject matter must be much closer to this Japanese fellow's, because 0.57 (1.2 negative density range divided by 2.1 subject brightness range or 7 zones) is what I'm shooting for (and I don't use a condensor enlarger either). IMHO, 0.615 is just too high for pictorial photography.

In any event, what I don't quite understand is, that Ilford claims not to use the ISO standard procedure to arrive at their film speeds but call it ISO on their film boxes. How does that work?

Dear Ralph,

As you say, the most important thing is that it allows realistic comparisons -- and often, if you like film A at -2/3 you'll like B at -2/3 too.

Incidentally, what about the flare factor reducing the subject brightness range to a lower image brightness range? Trivial with LF and a flare factor approaching unity; another matter with a 35mm SLR and a zoom where a (perfectly possible) flare factor of 2 reduces an SBR of 2.1 to an IBR of 1.8 -- another example of equipment and assumptions. Take 1.2 and divide by 1.8 and you get 0.67. I believe that 0.615 is probably the best compromise.

The story about Ilford film speeds is comparatively simple; at least, as I was told it a very few years ago. The ISO speeds on the box are, indeed, ISO speeds, in (I think, normally) ID-11. Except Delta 3200, obviously.

But because their different developers give different true ISOs, they quote dev times for EIs. Thus FP4 at 125 (true ISO maybe 100) in Perceptol is developed to above ISO contrast and FP4 at 125 in DD-X (true ISO close 200) is developed to below ISO contrast.

They admit that this is not perfect, but argue that most people can handle it better than multiple ISO speeds. Those who understand multiple ISO speeds can make informed guesses at the likely times for a given contrast.

This is also why they stopped giving separate dev times for G-bar 0.56 and 0.70. Most buyers just didn't understand it. Buyers may be more knowledgeable nowadays, but I doubt that Ilford can spare the manpower to draw all the necessary curves, etc.

Cheers,

R.

 

[Earl Dunbar]

Sorry, it's just one of those things that drives me up the wall when people say "The real speed is ISO...", because it almost never is.

Well, I don't think I uttered the "true speed" phrase, but were I to say that, I'd simply mean FOR ME ... my equipment, my processing, my preferences, etc.

The universe, indeed, does revolve around me.

 

[Richard Jepsen]

David Vestal's book, The Art of B&W Enlarging, convinced me to expose 135 Tri-X at 200 developed in D-76. With my setup tonality improved with a slight loss of sharpness. My negatives finally printed well on Ilford's MG IV as the negative density better fit the paper curve. Tri-X souped in Rodinal will have less shadow detail (about 1/3 stop) vs D-76.

 

[Roger Hicks]

Well, I don't think I uttered the "true speed" phrase, but were I to say that, I'd simply mean FOR ME ... my equipment, my processing, my preferences, etc.

The universe, indeed, does revolve around me.

Dear Earl,

I don't think you did either, which is why I made my clumsy attempt to apologize; an apology which I reiterate wholeheartedly. It's just that I had to start with a reply to someone...

Cheers,

R.

 

[gainer]

I do not care for a speed criterion based on a constant minimum density, though I can understand how it could be atractive to one who does not have an easel photometer. If one allows the film curve to be based on a percentage reduction of slope as it was years ago, there will be negligible speed difference between C. I.'s 0.56 and 0.66.

My question is not why shoot TX400 at 200, but how? I have said it before as have others, I think including Roger, that each of the posters to this thread might measure the same scene and either get different results or use different ISO values to get the same exposure. Yet I have not, or at least cannot remember when I did, see anyone state exactly their measuring system that allows telling me that I should use such-and-such a film speed without knowing my system, or how I can give proper advice without knowing the other person's system.

I'm not really being contentuous, just excercising my right to be in my 79th year on my name saint's feast day.

 

[Roger Hicks]

I'm not really being contentuous, just excercising my right to be in my 79th year on my name saint's feast day.

Dear Patrick,

Google Stephen Benskin and Delta X -- he explains how the current fixed density criterion is closer to the fractional gradient than seems reasonable.

You are quite right that fractional gradient is much superior, but Delta X works very well.

Cheers,

R.

 

[Earl Dunbar]

Roger: Understood.

 

[silvercloud2323]

Better shadow detail and smaller grain

Does this imply also that if you rate it for example at 800 ,you would get bigger grain ??

 

[Moose22]

Does this imply also that if you rate it for example at 800 ,you would get bigger grain ??

Thread more than 15 years old.

Not sure the dude you're asking questions of is even here.

 

[MattKing]

Sanders (Rolleiflexible) has dropped in a few times recently.
It would be great if he would post some more photos.

 

[Rolleiflexible]

Matt! More pictures? You will be pleased to know I am dabbling in the dark arts of Kallitypes these days. Here’s a platinum toned Kallitype in the tray this evening, of a 2010 image I shot onto Tri-X @ 200ei. (I contact-printed from a digital negative — I hope the APUG gods don’t smite me for my transgression.)

best regards,

Sanders
www.Flickr.com/sandersnyc
www.Instagram.com/sandersnyc

 

[Rolleiflexible]

I overexposed Tri-X (overexposed in the sense of putting an extra stop of light on the film over the box speed) because Tri-X is forgiving of too much light — you will not kill detail in your highlights. But err toward underexposure, and you lose all detail in the shadows. Metering is a bit of an art. An extra stop of light on the film gives you some protection against blowing your shot.

Or you could just throw away your light meter and dunk your Tri-X in Diafine and stop worrying about stops.

Sanders

 

[Rolleiflexible]

(OT: I miss Roger.)