jljohn
Well-known
I rejoined the Hassy Posse this week, and I am so far I am enjoying having an MF camera again. One of the things I am hoping to do with the Hasselblad is to make some long exposures (night images), and I am trying to understand Tri-X's reciprocity failure corrections. The info published by Kodak has both a time compensation and a development compensation. (For example, for an exposure that should be 10 seconds, Kodak says to make it 50 seconds AND reduce development 20%.) That's fine if I were using sheet film, but this is roll film. Let's say I want to shoot 3 long-exposure images in the middle of a roll. Is there a way to compensate given normal development? Thanks!
charjohncarter
Veteran
I agree that the Kodak charts are confusing. If you look at this Kodak PDF file:
http://www.kodak.com/global/en/professional/support/techPubs/f4017/f4017.pdf
you will see on page 2 they want you to change the stops or the time AND then change the development time.
On page 3 there is a much more detailed chart which gives the times on a graph curve (but no development recommendations).
Most of the people that I know (even sheet film users) don't really bother with the development changes. But I may be wrong, so I would experiment. I have found for TRIX the chart is pretty good. I have a little more trouble with the TMAX charts, but I am working on it.
http://www.kodak.com/global/en/professional/support/techPubs/f4017/f4017.pdf
you will see on page 2 they want you to change the stops or the time AND then change the development time.
On page 3 there is a much more detailed chart which gives the times on a graph curve (but no development recommendations).
Most of the people that I know (even sheet film users) don't really bother with the development changes. But I may be wrong, so I would experiment. I have found for TRIX the chart is pretty good. I have a little more trouble with the TMAX charts, but I am working on it.
Tim Gray
Well-known
TMAX 400 should give you better reciprocity behavior. I would think that a lot of people don't bother with the development changes - that's probably more to taste anyway. But I don't think you can really compensate for it.
It is suggested because as you get into really low light settings with long exposures, the shadows suffer from more reciprocity failure than the midtones and highlights do. So they end up even *more* underexposed than the midtones do. This drives the contrast up. Reducing development helps keep that in check.
Here some APUG links discussing reciprocity calculations. They might be informative or they might just be confusing
http://www.apug.org/forums/forum37/11566-reciprocity-misbehavior.html
http://www.apug.org/forums/forum48/41465-tmax-reciprocity-calculation-tmax-400-a.html
It is suggested because as you get into really low light settings with long exposures, the shadows suffer from more reciprocity failure than the midtones and highlights do. So they end up even *more* underexposed than the midtones do. This drives the contrast up. Reducing development helps keep that in check.
Here some APUG links discussing reciprocity calculations. They might be informative or they might just be confusing
http://www.apug.org/forums/forum37/11566-reciprocity-misbehavior.html
http://www.apug.org/forums/forum48/41465-tmax-reciprocity-calculation-tmax-400-a.html
Ljós
Well-known
ACROS as alternative
ACROS as alternative
I apologize for going off on a tangent here, but if you plan on doing a lot of night exposures, it can be worth your while to check out Fuji Acros 100. There is no reciprocity effect until 120 seconds of exposure!
This means that Acros, though nominally slower, can be effectively "faster" at nightime than some 400 speed films. Image quality is top notch.
Just something to consider.
Greetings!
Ljós
ACROS as alternative
I apologize for going off on a tangent here, but if you plan on doing a lot of night exposures, it can be worth your while to check out Fuji Acros 100. There is no reciprocity effect until 120 seconds of exposure!
This means that Acros, though nominally slower, can be effectively "faster" at nightime than some 400 speed films. Image quality is top notch.
Just something to consider.
Greetings!
Ljós
charjohncarter
Veteran
That's right, even TMax100 passes TriX pretty quickly.
charjohncarter
Veteran
I just went though my notes on TriX and one source gives a metered time of 8 seconds at new time of 20 seconds while the Kodak source gives a metered time of 8 seconds at a new time of 34 seconds. Also, my first source gives a metered time of 1 minute a new time of 5 minutes. And the Kodak 1 minute time becomes at little over nine. Now the Kodak times also recommend the development reduction. But still almost a stop difference at 8 seconds metered and almost a stop difference at 1 minute metered seems to be a lot.
My notes also showed significant differences with Tmax100 and Tmax400 times. I haven't done this much lately and TMY has become TMY-2 (TriX has probably changed too), but I did do a minute (25 seconds metered) exposure with Tmax100 (at 50) last week, my source was off it should have been closer to 40 seconds which is still slower than Barnbaum's and Don Kirby's. So, If I ever get the time I'll do my own testing.
My notes also showed significant differences with Tmax100 and Tmax400 times. I haven't done this much lately and TMY has become TMY-2 (TriX has probably changed too), but I did do a minute (25 seconds metered) exposure with Tmax100 (at 50) last week, my source was off it should have been closer to 40 seconds which is still slower than Barnbaum's and Don Kirby's. So, If I ever get the time I'll do my own testing.
charjohncarter
Veteran
I know this is on the interest level of a smelt in the California delta stopping water to the breadbasket of our country (US), but I did do some minor testing and this is the one that came out the best for me (go straight to the bottom for the chart, even the author tells you to do that):
http://www.phototechmag.com/index.php/archive/reciprocity
http://www.phototechmag.com/index.php/archive/reciprocity
jljohn
Well-known
Thank you all for the help on this. charjohncarter--thanks so much for Howard's article. I hadn't seen that, but he is meticulous, and I am looking forward to trying his chart times.
I finally got out yesterday and ran 2 rolls of Tri-X 120 through the Hasselblad, shooting details inside an old stone fort in the Boston Harbor Islands. Most exposures metered at around f/16 for 5 seconds, so I used the Kodak chart and bracketed generously. It will be interesting to see the results, especially in light of Howard Bond's research. I'll be back out there in about 2 weeks, so I will try again with his chart and see how it goes.
Regarding Acros: I actually used it a little for 35mm, and I liked it, but I hated the corkscrew curl that I just couldn't get rid of and made it darn near impossible to scan without 3 hands, and I really wanted to pick one film that I could use in most any condition across all formats and that wasn't likely to go away in the near future. Frankly, I just don't trust Fuji not to yank Acros from the market just as I really get used to it. So, I have settled on the classic--tri-x in D-76 1:1 in 35mm, 120, and eventually 4x5. I plan to shot this combo until I feel like I have mastered it and will try something else only when I have a technical need for something different. It is far to easy to be mediocre in my use of an excellent film and then complain that the film is the problem. So, I am going to accept Tri-X with its limitations (like its rather poor reciprocity failure) and use it until my negatives look like Salgado's.
I finally got out yesterday and ran 2 rolls of Tri-X 120 through the Hasselblad, shooting details inside an old stone fort in the Boston Harbor Islands. Most exposures metered at around f/16 for 5 seconds, so I used the Kodak chart and bracketed generously. It will be interesting to see the results, especially in light of Howard Bond's research. I'll be back out there in about 2 weeks, so I will try again with his chart and see how it goes.
Regarding Acros: I actually used it a little for 35mm, and I liked it, but I hated the corkscrew curl that I just couldn't get rid of and made it darn near impossible to scan without 3 hands, and I really wanted to pick one film that I could use in most any condition across all formats and that wasn't likely to go away in the near future. Frankly, I just don't trust Fuji not to yank Acros from the market just as I really get used to it. So, I have settled on the classic--tri-x in D-76 1:1 in 35mm, 120, and eventually 4x5. I plan to shot this combo until I feel like I have mastered it and will try something else only when I have a technical need for something different. It is far to easy to be mediocre in my use of an excellent film and then complain that the film is the problem. So, I am going to accept Tri-X with its limitations (like its rather poor reciprocity failure) and use it until my negatives look like Salgado's.
jan normandale
Film is the other way
Jeremy, I'm only addressing the TriX here we could go on for hours about other films and I'd join in but you asked a specific question so here goes.
Shoot the TriX and use a note pad to keep track of your exposure times and f stops. Then develop just one way only using only one developer, one dilution and one time with the identical agitations. It all sounds obvious and it is. When you begin to scan the negs you'll tell very quickly what you like or do not like.
Like you I have little short term comprehension of the arcane instructions for exposure, reciprocity curves and different developing processes. FWIW I seldom expose for more than 45 seconds and most often less. I usually shoot three exposures of 15, 30 and 45 seconds when unsure. More often I'll shoot night work at 10, 20 and 30 seconds for 400 ISO film.
Here's a link to both colour/C41 and BW... in the end it's about the image so how you arrive there is highly subjective and also interesting fun.
http://www.flickr.com/photos/jann/sets/72157594299276565/
Shoot the TriX and use a note pad to keep track of your exposure times and f stops. Then develop just one way only using only one developer, one dilution and one time with the identical agitations. It all sounds obvious and it is. When you begin to scan the negs you'll tell very quickly what you like or do not like.
Like you I have little short term comprehension of the arcane instructions for exposure, reciprocity curves and different developing processes. FWIW I seldom expose for more than 45 seconds and most often less. I usually shoot three exposures of 15, 30 and 45 seconds when unsure. More often I'll shoot night work at 10, 20 and 30 seconds for 400 ISO film.
Here's a link to both colour/C41 and BW... in the end it's about the image so how you arrive there is highly subjective and also interesting fun.
http://www.flickr.com/photos/jann/sets/72157594299276565/
charjohncarter
Veteran
Thank you all for the help on this. charjohncarter--thanks so much for Howard's article. I hadn't seen that, but he is meticulous, and I am looking forward to trying his chart times.
I finally got out yesterday and ran 2 rolls of Tri-X 120 through the Hasselblad, shooting details inside an old stone fort in the Boston Harbor Islands. Most exposures metered at around f/16 for 5 seconds, so I used the Kodak chart and bracketed generously. It will be interesting to see the results, especially in light of Howard Bond's research. I'll be back out there in about 2 weeks, so I will try again with his chart and see how it goes.
Regarding Acros: I actually used it a little for 35mm, and I liked it, but I hated the corkscrew curl that I just couldn't get rid of and made it darn near impossible to scan without 3 hands, and I really wanted to pick one film that I could use in most any condition across all formats and that wasn't likely to go away in the near future. Frankly, I just don't trust Fuji not to yank Acros from the market just as I really get used to it. So, I have settled on the classic--tri-x in D-76 1:1 in 35mm, 120, and eventually 4x5. I plan to shot this combo until I feel like I have mastered it and will try something else only when I have a technical need for something different. It is far to easy to be mediocre in my use of an excellent film and then complain that the film is the problem. So, I am going to accept Tri-X with its limitations (like its rather poor reciprocity failure) and use it until my negatives look like Salgado's.
I have to a little more on Howard Bond's chart, TriX works for me, while the Kodak and whoever came up with one on the back of my meter are too long. Be sure to let us know what your tests show and I'll see what the next roll shows.
Jan, is right don't mess with variables. Just do it the same every time.