Ian,
Lots of good advice here. In all my years of testing various films and developers, using a densitometer, I have only witnessed one combination that lost any significant speed vs the box speed; and that was Ilford HP5+ (8x10) tray developed in ABC Pyro. All other combinations, as others have already said, came in very close to box speed; typically, about 1/3 stop less for me and my working methods. Therefore, I wouldn't be concerned with any of it.
Thanks Alan. I have read all comments and found them interesting and I can no longer lose any sleep over this oneOriginally Posted by Alan9940
"maybe" indeed! When you make such statements, is it based on personal experience? Would you support the statements with examples? Sorry if I sound harsh, but forums, that should be an information resource, are degraded by such pseudo-information.esearing if you expose your Film at EI200 (...) but less details in highlights (maybe)
(...)
If you expose your film at EI800 (...) but more control over highlights
+1 and even more than 5 stops! see examples given by David Vestal in The Craft of Photography.Rich14 You can over-expose by an enormous degree (by as much as 5 stops) and you will still get excellent results. In fact, rating film at 1/2 or 1/4 box speed (1 or 2 stops more exposure than box speed) often results in increased quality
A related question - at least in my mind. A given film has 'printed box speed and a recommended development time at a certain temperature and a developer 'strength'[ ie 1: something].
NO PROBLEM, but what is the mechanism that makes 'Stand Development' work when the film is left in the developer for many times the duration specify by the manufacturer for a particular developer
just curiosity
regards
Tony
I'm no expert on stand development because I don't use that technique, but I do employ EMA (extreme minimal agitation) for certain film stocks. Basically, what happens is that the developer quickly exhausts itself in the dense negative areas (high values) while continuing to work in the thinner areas (shadows.) At some point, all developer activity stops. Then, an agitation cycle will start the process over again. Generally, one single agitation cycle is completed even with 'stand development.' All these development techniques can produce a different looking negative, but overall CI can reach what any normal development technique provides.
Reciprocity failure will give you more challenges than developers affecting 'box speed'. I rarely use anything except B or T for work under the redwoods. I have forgotten what 'normal' lighting conditions are!
"Landscapes exist in the material world yet soar in the realms of the spirit..." Tsung Ping, 5th Century China
Vaughn, what challenges do you find with reciprocity. When in the redwoods, what film do you use, what times do you incur and how do you process the negatives
My expose times range from a few seconds to many minutes. Generally, I meter to place the darkest shadow areas I want detail in on Zone III -- that is, I use my spot meter, read just the shadow, then add two stops of exposure to that reading. With conventional films, I will add one to two stops of exposure to correct for the film's poor response to the low level of light in the shadows. With TMax and Acros, I might just add one stop. I then read the brightest area in the scene and determine the development time based on that (and on experience).
I use the reciprocity "failure" to help increase contrast by increasing development (more exposure to get the shadows right, then let the highlights take off). I am using alt processes for print-making that have a need for high contrast negatives -- quite a bit beyond what the average user would want for contrast. So my method does not translate well for others.
Best bet would be to look up the reciprocity corrections for the film you are using - they will usually include development corrections as well. A lot will depend on the scene brightness range and your printing method. Test by going out, shooting, developing and printing!
When I first began using LF (1979), I did not know about reciprocity failure. I began by exposing at what I thought the exposure should be (using a Luna Pro), and I would take a second image with one more stop exposure. I found that the second exposure was easier to print. I ended up cutting the ASA in half as a general rule -- which got me overly dense negatives when I ventured out into the sun!
"Landscapes exist in the material world yet soar in the realms of the spirit..." Tsung Ping, 5th Century China
... but what is the mechanism that makes 'Stand Development' work when the film is left in the developer for many times the duration specify by the manufacturer for a particular developer...
While I don't have the requisite chemistry or physics background to answer Tony's question, I suspect that slowing down a chemical reaction in a particular spot enables better results than if it had proceeded there at full speed. I have noticed that printing a number of alternative processes slowly by using the open shade for the bulk of the exposure (slowing it down) took longer but also produced better results than if I had exposed it completely to the direct sun. Similarly, allowing the molecules of a diluted developer work on an area until exhausted before agitation to bring fresh developer to that point slows down overall development and may also bring about better results. (The UV present in the shade remains the same.)
Fuji's directions for developing its films offers an interesting analogy: It recommends an initial agitation of 60 seconds for the first minute and 5 seconds for each minute thereafter. Kodak, on the other hand, recommends 30 seconds for the first minute and 5 seconds each 30 seconds thereafter. The overall time of agitation remains the same but the developer is allowed to sit longer with the Fuji method.
Thomas
I found this interesting as I never think about adding more exposure above what I have determined for Zone III. I am right in thinking that although you have worked out your exposure for Zone 3, in effect, you are actually putting them on Zones 4 / 5 depending on what film you use
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