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Deconfusion request -B&W film exposure latitude
How much exposure latitude can I get with B&W films? Worst and best please? Thanks, Cheers, Alan -- e-meil: there's no such thing as a FreeLunch. |
#2
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Deconfusion request -B&W film exposure latitude
"Alan Browne" wrote in message
... How much exposure latitude can I get with B&W films? Worst and best please? It depends on how you develop it. By underdeveloping, you lower the effective speed and increase the exposure latitude. By overdeveloping, you do the opposite. That's for conventional black-and-white films. If you need extreme exposure latitude, I suggest a C-41 (color process) black-and-white film such as Kodak Black & White Plus 400 or T400CN. The latitude is something like 1 stop under, 5 stops over. Others will have more exact answers. |
#3
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Deconfusion request -B&W film exposure latitude
It depends a lot on the film. The Kodak TMax films are extraordinary, and
sometimes hard to print as a result. The old Verichrome Pan was designed for non-adjustable cameras and also gave remarkable results over a wide range of exposure. Modern films, like FP4+, are not quite so wide. You can get a good idea from looking at the film's characteristic curve. Determine the exposure range (log E) for which you get a useful change in density. Most outdoor scenes require about seven stops (delta log E of 2.15) to capture a good likeness of the image. Any extra available from the film is the true "latitude". Note however that many scenes require a much shorter exposure range, so the latitude can be greater (if you adjust the print contrast). "Alan Browne" wrote in message ... How much exposure latitude can I get with B&W films? Worst and best please? Thanks, Cheers, Alan -- e-meil: there's no such thing as a FreeLunch. |
#4
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Deconfusion request -B&W film exposure latitude
Hi Norman,
Could you answer the following: For a film like TMax (or any other if you prefer) what is the latitude range in stops. Assume metering for 18% grey and the film is exposed as rated. I'm not interested (at this point) in what can be printed, I'm interested in what can be recorded. Thanks, Alan. Norman Worth wrote: It depends a lot on the film. The Kodak TMax films are extraordinary, and sometimes hard to print as a result. The old Verichrome Pan was designed for non-adjustable cameras and also gave remarkable results over a wide range of exposure. Modern films, like FP4+, are not quite so wide. You can get a good idea from looking at the film's characteristic curve. Determine the exposure range (log E) for which you get a useful change in density. Most outdoor scenes require about seven stops (delta log E of 2.15) to capture a good likeness of the image. Any extra available from the film is the true "latitude". Note however that many scenes require a much shorter exposure range, so the latitude can be greater (if you adjust the print contrast). "Alan Browne" wrote in message ... How much exposure latitude can I get with B&W films? Worst and best please? Thanks, Cheers, Alan -- e-meil: there's no such thing as a FreeLunch. -- e-meil: there's no such thing as a FreeLunch. |
#5
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Deconfusion request -B&W film exposure latitude
Okay, my confusion remains. How many stops can I get onto the film. For example if I meter for a specific exposure and the scene has detail going 6 stops above and 6 stops below, how much will I actually record? Is this a question of 'range' rather than latitude? Cheers, Alan. Norman Worth wrote: It depends a lot on the film. The Kodak TMax films are extraordinary, and sometimes hard to print as a result. The old Verichrome Pan was designed for non-adjustable cameras and also gave remarkable results over a wide range of exposure. Modern films, like FP4+, are not quite so wide. You can get a good idea from looking at the film's characteristic curve. Determine the exposure range (log E) for which you get a useful change in density. Most outdoor scenes require about seven stops (delta log E of 2.15) to capture a good likeness of the image. Any extra available from the film is the true "latitude". Note however that many scenes require a much shorter exposure range, so the latitude can be greater (if you adjust the print contrast). "Alan Browne" wrote in message ... How much exposure latitude can I get with B&W films? Worst and best please? Thanks, Cheers, Alan -- e-meil: there's no such thing as a FreeLunch. -- e-meil: there's no such thing as a FreeLunch. |
#6
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Deconfusion request -B&W film exposure latitude
Alan Browne wrote:
Okay, my confusion remains. How many stops can I get onto the film. For example if I meter for a specific exposure and the scene has detail going 6 stops above and 6 stops below, how much will I actually record? Is this a question of 'range' rather than latitude? Cheers, Alan. Norman Worth wrote: It depends a lot on the film. The Kodak TMax films are extraordinary, and sometimes hard to print as a result. The old Verichrome Pan was designed for non-adjustable cameras and also gave remarkable results over a wide range of exposure. Modern films, like FP4+, are not quite so wide. You can get a good idea from looking at the film's characteristic curve. Determine the exposure range (log E) for which you get a useful change in density. Most outdoor scenes require about seven stops (delta log E of 2.15) to capture a good likeness of the image. Any extra available from the film is the true "latitude". Note however that many scenes require a much shorter exposure range, so the latitude can be greater (if you adjust the print contrast). "Alan Browne" wrote in message ... How much exposure latitude can I get with B&W films? Worst and best please? Thanks, Cheers, Alan Alan, It's a function of not only the film and exposure but the processing. From my casual reading of it over the years, the best you can get is about ten stops, and I think a typical range is more like 7 stops. It has everything to do with your particular combination of film, exposure, and chemistry. For the extremes you want you'll need to pull the film, maybe overexpose two stops and underdevelop two stops, processing for longer than normal with a more dilute developer. --- David Meiland Friday Harbor, WA http://davidmeiland.com/ **Check the reply address before sending mail |
#7
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Deconfusion request -B&W film exposure latitude
Okay, my confusion remains.
How many stops can I get onto the film. For example if I meter for a specific exposure and the scene has detail going 6 stops above and 6 stops below, how much will I actually record? Is this a question of 'range' rather than latitude? Cheers, Alan. Unless you are metering an illuminated light source (or reflection from an illuminated light source) the maximum metered range of a scene is about 10 stops total (usually at high altitude or desert areas), and 7-8 stops is more likely to be observed in areas of normal humidity. For scenes that are not in bright sunshine, the range is obviously less. How much you can fit on film depends on development time (which determines negative contrast). The less the development time, the greater range of scene reflectance that will fit on the film. |
#8
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Deconfusion request -B&W film exposure latitude
"Alan Browne" wrote in message . .. Okay, my confusion remains. How many stops can I get onto the film. For example if I meter for a specific exposure and the scene has detail going 6 stops above and 6 stops below, how much will I actually record? Is this a question of 'range' rather than latitude? Yes, and you can read it off the film's characteristic curve. That's why they give those curves in the data sheet. Each unit (from 2.0 to 3.0 for instance) is a factor-of-10 brightness range. It depends on development. You get more range if you underdevelop. |
#9
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Deconfusion request -B&W film exposure latitude
Here's a worked-out example using data from:
http://www.kodak.com/global/en/profe...16/f4016.jhtml T-Max 100 film ("new" variety, 100TMX), developed in D-76 in a small tank for 6 minutes at 68 F, has a plotted range from -2.0 to nearly +1.0 and is not topping out at the right-hand end. I estimate its usable range is probably 3.5 log exposure units, with a maximum density of about 2.2 (which you should be able to scan or print). 3.5 log exposure units = a factor of 10^(3.5):1 = 3000:1, roughly = 12 stops, roughly. You can develop the film even less and get an even wider range. When the film is underdeveloped this much, you should set your meter at 50 or 25 rather than 100. Experimentation will be in order. |
#10
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Deconfusion request -B&W film exposure latitude
Michael A. Covington wrote: Here's a worked-out example using data from: http://www.kodak.com/global/en/profe...16/f4016.jhtml T-Max 100 film ("new" variety, 100TMX), developed in D-76 in a small tank for 6 minutes at 68 F, has a plotted range from -2.0 to nearly +1.0 and is not topping out at the right-hand end. I estimate its usable range is probably 3.5 log exposure units, with a maximum density of about 2.2 (which you should be able to scan or print). 3.5 log exposure units = a factor of 10^(3.5):1 = 3000:1, roughly = 12 stops, roughly. You can develop the film even less and get an even wider range. When the film is underdeveloped this much, you should set your meter at 50 or 25 rather than 100. Experimentation will be in order. Thanks Michael. Alan -- e-meil: there's no such thing as a FreeLunch. |
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