kully said:
Thanks for starting this thread Pau. And to you Allan for undertaking your test later on today.
I would like to again applaud Pau's enthusiasm for experimentation. I fear that I'm going to seem more argumentative than I am. In a denotative sense, I am arguing. But connotatively, that is a negative thing. I am debating the topic with him and have now come to a conclusion. It's the opposite of his, but I am just debating the topic based on what I know. I am not Bill Troop or anything. I know that.
Allan,
I don't understand all of these zones, but I know what I get with what my VCII and what my eye tells me to meter off and I've learned to work with that to get negatives I can print (or scan).
If I set it [VCII] at 3200 and get 1/4@f/4 and then compensate by setting 1/15@f/4 instead and carrying on like this for a roll and then checking the roll after Pau's dev' method - is that OK?
First, sorry that I am using some much zone terminology. It's the only real way for me to do it without writing even longer posts, but I should have apologized that I was going to dip this thread into zonie-land.
You're doing a pretty good method, yes. What you're doing, logically, is "okay, my meter says that 1/4 f4 is middle grey. I'm willing to just bank on the shadows being 2 stops darker so I'll decrease exposure by 2 stops." That's fine. It's true that shadows may be even darker, but it's still a good method to use.
I just realized that we don't even know if Pau adjusted from his incident readings. If not, then he's overexposing his shadows by 2 stops as it is, even if it's a normal contrast scene. So now we're down to...EI 800 from his results. Hm.
And yes, evaluating by negatives is always fine. Sometimes you'll get one that isn't what you wanted and you can see it right away. But you live with the ones you miss, and cherish the ones you get, right? FWIW, I am not a big test guy. I have done a few (I did a big Delta 100 in 3 different developers test a while back, which I can repost if people are interested), but I generally do as you do, except I do spot meter the shadows specifically. But the whole roll isn't at the same contrast level, usually, so I end up with a few frames that are over developed, a few that are under, etc. So it goes.
Apologies for my stupidity but I'm utterly confused by this sentence
Please don't apologize. If I don't confuse at least 1 person per thread with what I write then I must have taken some magic "suddenly write good" potion. I am often too verbose. My fault.
"You can set your ISO dial to 1000000000000 if you wanted to and get great looking negatives, but that doesn't mean that's your EI."
Film - all film - needs a certain amount of light to get any kind of reaction at all with the silver and the developer. Certain films need more than others. And those films in certain developers need even more or less than others. This is the foundation of how some developers increase speed while others decrease it. Rodinal, used normally, requires more light to have hit the silver to even begin to react and build density than, say, Microphen. Since those low density areas are shadows, and shadows are how we define film speed, we say Rodinal is a speed-decreasing developer, and that Microphen is a speed-increasing one.
I'm going to get a bit deeper her before I get into the basic example. My apologies. There are common references to film "curves." These curves, known as H&D curves, have "toes" and "shoulders." If you were to draw a graph of density vs. exposure, it would not be a straight line. In other words, if you give it amount of light X and it yields density Y (and density means detail for the most part), giving it 2X doesn't necessarily mean 2Y. This actually only applies at the toe, at the bottom, and the shoulder, at the top. The curve is like a really lazy S. So there is a flat area where as you increase exposure from 0 to whatever (still in a very low range of light) there is almost _no_ change in density. The film will still be blank in that area. But then suddenly you hit this threshold, and the curve becomes linear. 3x>3y, 4x>4y, etc. Then all of a sudden at the top as you give it more and more it flat lines again. That's the shoulder. That makes sense - you can't give more than 100% silver to an area
🙂.
Okay. So that's why shooting TXT at 12800 has to be done carefully, since at that speed, at night, you're shadows are _so_ dark that the chance of you getting out of the toe is really low. BTW, just past the toe would be detailed shadows, or Zone III. Roughly.
So, the practical example. Let's say I have my camera set at ISO 12800 (I think that's the highest any of my SLR's go to). I can go outside, in open shade (ie - even light), in the middle of the day, and take a shot. Now, it'll be like f22 and 1/4000, but I did it. And the negative will look good, because there was a lot of light there. And it was an evenly lit scene so the shadows weren't crazy dark. So I got EI 12800, right?
Well, maybe. Actually, almost certainly no. This is like when people do noise tests with digital SLRS in the middle of the day. Look, no noise! Well, when there is a lot of light around then of course the noise is low. The problem is when you shoot in situations that, even with proper exposure, it's still at least really dim. There isn't a lot of light around in general to hit the sensor. Then what does the noise look like? In the case of film, if it's overall dim, and now you're shooting at 1/15th at f2, are you out of the toe? What if that was your incident meter and now you go to 1/4 at f2? It's about the quality of light, even though they are equivalent exposures.
Really low contrast, even light, lots of light bouncing around - you can get great results with your ISO dial cranked all over the place. But if there is even just normal contrast and it's dark to begin with, and you want shadow...well, it's hard to get out of the toe. Oh, and at night, spot metering will tell you that it's not a normal contrast scene. Detailed shadows will be...5 stops darker than your meter reading. Something like that.
Does that make sense? I had trouble writing it so perhaps I just made it worse
🙂.
I know I like HP5+ at 1600 in DDX, I've tried it at 3200 as well but I don't like it.
What you're probably finding there is just the contrast issue with pushing. You've decreased overall exposure to the film, which means the shadows vanish into the toe (I'm having fun using the word "toe" as a region). You then overdevelop (which is the 2nd part that makes up "pushing" film - it's both underexposure and overdevelopment, not just 1 or the other) to bring your midtones up into a usuable area, but then your highlights go up, too, and they blow out. Voila, super high contrast. Not always a good look.
But you'll note something - you've lost those shadows, right? If speed is based on shadows...then clearly HP5 in DDX is not a 1600 or 3200 speed film. Maybe at 1600 the negatives look acceptable to you - that's great! I mean it. If you're happy, that's what matters. But from a film speed perspective is it _not_ a 1600 speed film just because you are happy with the results.
dang, I write a lot. sorry.
allan