How do they/you do this?

[timbo10ca]

Tim, Along with any type of regimen in processing one must consider the materials that one is using. Not all films are capable of reaching the same density scale (contrast range). Once the maximum development for a given emulsion has been reached any additional development will only serve to build uniform fog. That fog has the effect of diminishing contrast since you are adding something to the lower density ranges that was not there previously. One would think that this fog would be linear in it's effect on all densities...this is not the case because one must consider the percentage variable compared to the specific density.

Donald Miller

I use FP4, HP5 and Delta100. I rate each at half box speed, but up rate them to approach box speed as I increase development. By around about N+2 or 3, they are at box speed. I use Pyrocat HD for FP4 and HP5, HC-110 for HP5 for ziatypes (I need mega development for contrasty negs. I haven't tried silver printing one of these, but it may already have what I'm after???). I use Rodinal 1:50 for Delta100. Are any of these appropriate for what I'm after (I'd rather not add a 4th sheet film if possible)? It was mentioned that HP5 would not be good, but I'm not sure I understand why, as it has such a nice long straight curve- I thought this was what I'd be after (to have all the tones on the curve in order to expand them and not just add density to "mush")...
Is it because it doesn't expand well (I've been told it's better for bringing contrast under control vs trying to get more)?

Tim

[timbo10ca]

If you expose beyond 1 sec. then the darker areas in the image get less exposure than the lighter ones, compared to a faster exposure. Its a way of dropping out the darker tones while leaving the lighter tones somewhat unaffected, so its not an "increase in contrast" as mentioned by another poster.
Approached from the opposite perspective, keeping the shadow detail in images longer than 1 sec can be a challenge, involving big increases in exposure and changes in dev. time. Doesn't it make sense that not making those changes would result in the loss of shadow detail?
I had a project in the 90's shooting fresh picked vegetables next to a single window where I used this effect for many shots to help give emphasis to the shapes. This example is a good one as the detail and texture in the white squash is retained which wouldn't be the case if there had been increased development.
JY

John- that's gorgeous, even on a computer screen.....

[timbo10ca]

I find the effect nice if there are a lot of small areas of deep shadow that I do not mind going clear on the negative. So I will increase exposure a little (not as much as recomended) to counter the reciprocity failure, and instead of the recommended reduction in development, give more development. (a good carbon negative for me is unprintable in silver gelatin -- too much contrast).
Vaughn

Why would you increase exposure to counteract the reciprocity, if that's what you're trying to take advantage of? Am I correct in thinking that you are relying more on the increased development to bring up the mids and highs by not giving enough reciprocity compensating exposure. This "not enough" exposure then underexposes the lows, then increased development does nothing further for them because there's nothing really there? End result is expanded scale- lows are lower than would be with no reciprocity and given N dev, and mids and highs are where they would have normally been with no reciprocity and given N dev?

You say you would overdevelop rather than the "recommended reduction". Is it standard to N- develop when you are photographing a normal scene and have to use reciprocity exposure? I guess it makes sense (in light of this discussion) if you don't want to have the scene look contrasty, and look normal as if you made the image with a shutter speed faster than 1 sec. This may be why I have a couple images taken on D100 where I had reciprocity in the exposure and when developed it looked really overexposed. When I looked closer, I had blacks, so it must have been overdevelopment (I gave N for one 5 stop scene and N++ for the other flat scene). I thought I had messed up by using the formula I use for FP4 reciprocity (see below) without thinking and had overexposed...... Now I'm led to believe the same formula should apply because it has the same curve as FP4.

Right now I'm using a formula found either here or on APUG for FP4 and HP5 for reciprocity. I wasn't happy with the loose chart the company publishes and wanted something more specific. The D100 film curve looks similar, so I thought I could use the same formula. I think it's x^1.48, with x=metered time. Does anybody use this? Is it OK for all 3 films? Should I just follow the Ilford charts?

It was mentioned that on Delta, I could get one stop of added contrast (zone scale expansion) for a 30 sec exposure and 2 zones for a 2 minute exposure. Is this pretty standard with this film, or is it quite highly dependant on developing technique (and need careful testing like everthing else with film/developing)? If it's pretty standard, would I expect similar additional zones with my other 2 films for these added times?


Tim

[mandoman7]

John- that's gorgeous, even on a computer screen.....

So you see through my BS... don't let anyone else know, OK?
Thanks, though. I felt pretty lucky when I saw that one come up in the darkroom.

[willwilson]

Why would you increase exposure to counteract the reciprocity, if that's what you're trying to take advantage of?

This should read: "Why would you increase exposure to counteract the reciprocity failure, if that's what you're trying to take advantage of?" reciprocity failure gets shortened to reciprocity often.

Vaughn means, if your meter reads 4s @ f16 and your film actually requires 8s @ f16 then he might under-compensate for the reciprocity failure of his film and give an exposure of 6s @ f16.

This is a good quick read on the subject, only slightly boring. http://en.wikipedia.org/wiki/Reciprocity_(photography)

You say you would overdevelop rather than the "recommended reduction". Is it standard to N- develop when you are photographing a normal scene and have to use reciprocity exposure?

Yes, a reduction in development is standard for long exposures to reduce contrast and bring the level of contrast on the negative back closer to normal. But we want more contrast so you have to crank up the juice.

Now I'm led to believe the same formula should apply because it has the same curve as FP4.

No. See this thread. http://www.largeformatphotography.in...ad.php?t=53298

and this link. Although you should always do your own testing. http://www.willwilson.com/articles/0...ciprocity2.pdf

Should I just follow the Ilford charts?

No. see above.

It was mentioned that on Delta, I could get one stop of added contrast (zone scale expansion) for a 30 sec exposure and 2 zones for a 2 minute exposure. Is this pretty standard with this film, or is it quite highly dependant on developing technique (and need careful testing like everthing else with film/developing)? If it's pretty standard, would I expect similar additional zones with my other 2 films for these added times?

I think I said that...I don't have any numbers or facts to back that up btw. It's just experience with that film.

No, it's not standard between films, but all films behave in similar ways within limits. You need to test.

[timbo10ca]

Thanks Wil- I appreciate that some fine tuning will be necessary, but for a normally lit scene, if I'm using Rodinal 1:50 at 68F for D100, should I be using Lenny's or your (Howards?) table as a starting point?

As I have nothing else for FP4 or HP5 to go on, and the HP5 is inaccurate according to Howard, should I be using his HP5 numbers? Will these be an OK starting point for both Pyrocat HD and HC-110? What should I do about FP4 in Pyrocat HD? I can only assume the table is inaccurate for it as well, but it seems that Lenny is pretty loose with his time additions so I wonder how specific I have to be. Again, I understand that these tables are for normally lit scenes and I have to rely on estimations and experience when I get into low light scenes with bright spots in them and adjust how I'm exposing and developing based on what I'm trying to achieve.

For this type of photo I'm after, what would be the best film/dev combination I currently am using?

I just want to get things straight in my mind over what I need to do:
1) get accurate tables for these 3 films for normally lit scenes
2) establish for (each film) the time period that give additional stops of contrast. For D100 I can at least start with your observations. Hopefully I can find other peoples' for FP4 and HP5 as a starting point.
3)) find development (minus) times for these higher contrast exposures to make them "normal". Or can I use my established N-1, N-2 times for non- reciprocity developing? (please say yes!!!)
4) find dev times (plus) times to add even more contrast (again, hopefully I can use my pre-established times for non-reciprocity exposures). Same thing if I want to compress more than normal using N- developments.

Tim

[Jehu]

I must plead guilty to just scanning over this thread without reading every post. Some are quite long. Anyway...

Some of those shots look like they've been Solarized. Has that been covered in any of the posts that I read too quickly?

After reading Tim's original post, it seems like that may be the answer to his question.

Either way, it's a technique that always deserves some discussion. I haven't tried it yet but I plan on it as soon as I get my darkroom finished.