Revisiting Tri-X 400 After Three Decades
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I haven't used Tri-X in either form since college Photography #101 and Photography Large format 4X5 courses. I later went Agfa and Ilford and it's been pretty much Ilford ever since the demise of Agfa. After watching this video I have to say I could gladly use Tri-X if it were even close to the price of HP5+ or if it offered a big big advantage pictorially over Hp5+, but I just don't see that much difference for my type of photography. Keep up the good work Andy and don't get too fat on all those donuts.
The two graphs were very similar in the shadow area so the slight difference could be consistent with the tree shots and yet the scene with the house and trees revealed a much bigger difference. So might it be that only where the shadow area is a large portion of the scene as it was in the house and trees does the more open HP5+ shadows win
In what I'll term the kind of shot that most users might take such as the pillar and steps with some dark areas I can see why Tri-X wins with a lot of newcomers to film where highlights are more important to them
That leaves us with the point that Lachlan Young makes on Photrio, namely that Kodak and Ilford differ in what they recommend for the equivalent of Contrast Index. If you develop both to the same equivalent Contrast Index you get virtually identical results However ín the case of HP5+ Ilford gives the same time for both films in either D76 or ID11 ie. 7.5 mins while I can find nothing about "foreign " films ie. non Kodak ones in D76 so I can find no comparison but for Tri-X 400 Kodak gives 6.75 mins.
So if the 2 developers are identical in action then does this mean that 6.75 mins or 45 seconds less for HP5 gives the same Contrast Index
Would 45 seconds less for HP5+ reduce shadow detail to that of Tri-X and also improve highlight to that of Tri-X? It would seem not based on the two curves
That's a few good questions that spring to my mind for which I have no good answers
Incidentally Andrew if I had been in a darkroom for 7 hours from 4:00 am like you and then gone "shooting" in the rain I'd have pulled up my hood, sat down by that tree and been delivered home 24 hours later by the police, saying to my wife : "Good news, we found him asleep, hypothermic but otherwise well under that tree you told us about"
pentaxuser
In what I'll term the kind of shot that most users might take such as the pillar and steps with some dark areas I can see why Tri-X wins with a lot of newcomers to film where highlights are more important to them
That leaves us with the point that Lachlan Young makes on Photrio, namely that Kodak and Ilford differ in what they recommend for the equivalent of Contrast Index. If you develop both to the same equivalent Contrast Index you get virtually identical results However ín the case of HP5+ Ilford gives the same time for both films in either D76 or ID11 ie. 7.5 mins while I can find nothing about "foreign " films ie. non Kodak ones in D76 so I can find no comparison but for Tri-X 400 Kodak gives 6.75 mins.
So if the 2 developers are identical in action then does this mean that 6.75 mins or 45 seconds less for HP5 gives the same Contrast Index
Would 45 seconds less for HP5+ reduce shadow detail to that of Tri-X and also improve highlight to that of Tri-X? It would seem not based on the two curves
That's a few good questions that spring to my mind for which I have no good answers
Incidentally Andrew if I had been in a darkroom for 7 hours from 4:00 am like you and then gone "shooting" in the rain I'd have pulled up my hood, sat down by that tree and been delivered home 24 hours later by the police, saying to my wife : "Good news, we found him asleep, hypothermic but otherwise well under that tree you told us about"
pentaxuser
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Another nice bit of research indeed!
In my many and various tests - both sensiometric and just shooting and trying things - I've never found a film that hit full box speed EI with conventional development. The dark shadows of Tri-X you're experiencing are - in my experience - due to using too high an EI.
I have found two remedies for this:
- Shoot at half box speed and underdevelop about 20% from published recommendations. This works better with more dilute developer choices because the film sits in solution longer, giving the shadows more time to get there.
- Use full box speed for the EI, but semistand or EMA process the film to get full shadow speed. These days, I actually expose at about 1/3 f/stop lower speed than box to give myself a bit of protection for shadow detail. HOWEVER, I have found that doing this can blow out highlights really easily, especially with films like Tri-X.
Now when I do this, I use very highly dilute developer. These days, I am doing EMA for an hour in Pyrocat-HD diluted 1.5:1:300 with 90 sec initial agitation and 10 sec agitations at 21 and 41 minutes respectively. This helps keep the highlights in bounds and is long enough time to reach full shadow speed.
For larger formats, D-23 1+9 with 0.5g/l of sodium hydroxide added is also a good combo. But it gets so sharp that grain on 35mm can become noxious.
Your samples as processed definitely show more shadow detail in HP5+ and more contrast in Tri-X. I never did warm up to HP5, finding it grainier than I wanted in 35mm.
There may be remedies for as you outline this but that hardly seems to explain why in the shot of the trees and the house the Tri-X shadows were more pronounced that those in the HP5+ shot
In the tree shots the difference was fairly marginal between the two films tempting me into thinking that the slight difference in the two curves might explain it but that thought was largely shattered when I saw the trees with part of a building shot where the Tri-X shadows were much darker
pentaxuser
Shadows too dark is an indication of insufficient exposure for the development scheme in use. i.e., The selected EI is too high, which was sort of my first point.
In my experience, Tri-X with conventional agitation never hits full box speed with any developer I have tried: D-76, DK-50, HC-110, PMK, & Pyrocat-HD. More generally, among these developers at least, I've never seen any film hit full box speed when agitated and developed the usual way. The film simply doesn't sit in developer long enough to reach full shadow speed.
I first proved this to myself 25 years ago with a lot of densiometric testing. I've confirmed it since anecdotally by looking at- and printing negatives. The usual MQ developers as well as HC-110B seem to hit about 1/2 box speed with normal agitation schemes. PMK and Pyrocat seems to deliver a bit more speed - 1/3 to 1/2 or so - but still not full box speed.
You could attribute this to my thermometers, light meters, and so forth, except - like I said - I did some detailed densitometry back when which more or less confirmed this (for all but Pyro developers since my densitometer cannot handle color).
Thanks for your reply but my point was the difference between HP5+ and Tri-X in terms of shadow detail in one of the pictures that needs to be explained
Your remedies for improving shadow details would apply to both films given that there is a difference in Andrew's shot with his agitation then surely that difference remains when your methods are applied?
pentaxuser
Your remedies for improving shadow details would apply to both films given that there is a difference in Andrew's shot with his agitation then surely that difference remains when your methods are applied?
pentaxuser
It could be that the HP5 gets closer to box speed I don't know as I've never tested or.
With EMA or semistand, I'd expect both to hit full box speed or very close to it if the film was left in developer long enough
This might be one explanation but as far as I can discover both films achieve box speed in D76 which was Andrew's developer. None of the even small shadows on the close-up of the tree looked quite as dark in the HP5+ shot but it was marginal i.e. most viewers unless they were looking specifically at the shadow areas would not have noticed it but in the large shadow area in the trees and house shot there was a clear difference
I think we may not have got to the bottom of this yet
pentaxuser
If you want to generate a meaningful, objective comparison “at home” of two films developed in the same developer, do the following.
1. Expose the two films in the same way (preferably contacting a step tablet/wedge, but a no-flare in camera method can suffice.
2. Find the development time for each film so that the two films are developed to the same gradient (preferably approx. 0.6 +/-). This might take several tries. Compare the resulting curves.
3. Photograph a colour checker with each film and develop for the times determined in step 2. This will give you a reasonable sense of spectral sensitivity differences with a given exposing light source.
Of course, you can also repeat this for different light sources (tungsten, daylight…).
It can be tedious work, but that’s how you get the answers. Understand what a test is testing/not testing.
Yes you have convinced me of the last point quoted so I'll leave it to others Interestingly Andrew's colour checker taken by either film looked the same to me and if I recall correctly, the same to Andrew as well
pentaxuser
That's pretty close to what I've found with Tri-X as well
If Tri-X is actually slower than HP5+ by up to more than a stop (250 v 650) why does the ISO test which as far as I know uses D76 as the test developer show both as being genuine 400 speed films? Andrew used D76 as well
Have the testers made a mistake in the test or is there an alternative explanation?
Thanks
pentaxuser
Have the testers made a mistake in the test or is there an alternative explanation?
Thanks
pentaxuser
There is ASA/ISO and there is EI. They are different. By which I mean:
ISO speed has a very specific, narrow and rigorously defined test criteria.
EI does not. EI is based on your thermometer, meter, agitation style and so forth. Even densitometry doesn't entirely clear this up because there isn't anything particularly magical about defining the EI to be the conditions under which Zone I is 0.1 DU above FB+F. Why not 0.009 or 0.11 or ...
The point is that "real world" speed is hard to completely standardize on because of each photographer's own variables.
That said, using 0.1 DU above FB+F as a baseline and agitating for 5 seconds every 30 seconds, using a decent thermometer, and a meter in decent calibration state, I have found pretty much all films to have an EI around 1/2 box ISO for all non-Pyro developers. I have not, however, actually measured HP-5+ and thus have no particular insight.
When I saw Andrew doing this interesting test at EI 400, I immediately thought, "The Tri-X is going to have poor shadow detail." It would seem that was, indeed, the case.
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No, the films are the same speed, confirmed in my tests. But that speed is about 1/2 ISO speed. There is no such thing as "box speed".
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The ISO criteria do not specify a required developer. It is up to the manufacturer. This change to the standard was made in 1993.
Ilford sometimes indicates which developer was used in their speed testing but they seem to be removing that detail over time. For example last I checked the tech sheet for FP4+ indicates ID-11 (D-76) was used for ISO speed determination.
Specifying which developer was used is not quite as big a deal as one might assume. In reality the speed differences between most general purpose developers are extremely small.
Both Tri-X 400 and HP5+ are ISO 400 and these are both reputable companies. I have tested Tri-X 400 in D-76 and guess what... ISO 400 criteria were met. Not much of a surprise. Maybe Ilford found the speed of HP5+ to be slightly higher than 400 but chose a conservative rating of 400. I don’t know, but that would have to have been a very small margin.
As for the EI people choose, people doing typical “personal EI” tests usually end up with an EI roughly 1 stop slower than the ISO speed, which is not really revealing anything because they are usually using a Zone System-style speed criterion, which by definition is 2/3 stop slower than the ISO speed.
There used to be an "official" ASA developer, which I believe to be close to the Adox MQ Borax developer, very similar to D-76. When the T-Max films came out, they were packaged with "EI" on the package, because they do not reach full speed with D-76, I believe.
And that's kind a central point here. What you call "my EI" has a lot to do with what you see as proper shadow detail.
Independent of all that, though, I will say that most of the stuff I see shot a box speed has thin shadows at least if its agitated normally and for recommended time. That extra stop that is built into "0.1 DU over FB+B" saves a fair bit of bad negatives.
Up until the standard was revised the specified developer was (1l):
Metol 0.5g
Sodium sulfite (anh.) 40g
HQ 1g
Sodium carbonate (anh.) 1.5g
Sodium bicarbonate 1.0g
KBr 0.2g
pH 9.4 +/-0.2
The story goes that the earlier T-Max films did not reach film emulsion speed in this developer. It wasn’t an issue with D-76. Apparently D-76 was the release developer for the T-Max films.
The difference between the ISO criteria and the Zone System is not the 0.1 above B+F. That density is part of the ISO criteria. The difference is where that exposure is relative to the metered exposure. The ISO measurement is essentially a special case of Delta-X which is a method for estimating the fractional gradient speed, and the fractional gradient was a relationship between the gradient at the shadow exposure and the overall gradient, with this relationship having been based on print judgement speeds. I’m skipping a lot, but that’s basically the lineage of the ISO speed determination. The important thing is that ISO speeds are rooted in print quality, and that ultimately what counts is contrast in the shadows rather than just a fixed density.
Perhaps the simplest approach to reconciling Zone System and current ISO speeds is that in 1960 the ~1 stop safety factor was removed from black and white negative film speeds, which is why the speed ratings doubled. Prior to that the “box” and Zone System speeds would have been pretty much the same.
MattKing
Moderator
Exactly - the ISO standard reflects print quality considerations more than classic Zone System or other speed related determinations reflect print quality considerations.
A Zone System approach will generally give you more detail in the shadows, at the expense of highlight rendition.
And in most cases, people respond more to the highlight rendition in a print than they do to what can be found in the shadows.
Unless they are in the relative small subset of people who are Zone System devotees, who seem to gravitate more to the dark.
If you are unsure if someone is a Zone System devotee, it is often a good indicator if they have a beard and wear wide brimmed hats ......
.
If you are unsure if someone is a Zone System devotee, it is often a good indicator if they have a beard and wear wide brimmed hats ......
What about the ability to play the piano as well ?
pentaxuser
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