Expose for shadows, develop for higlights
Well, this will sound really stupid from my side, but...
I never understood what that rule means. Yes I know that is one of oldest and firmest rules, but I never used it on purpose. So I would really love if someone explain it to me practically.
I belive exposing for shadows means that I measure light in shadows to get details in shadows (or not to have details if I don't want), but what developing for higlights means? For example if I use Ilford ID11 and FP4, at Ilford recommended 8:30 minutes developing time, how practically to use mentioned rule, how and why to change developing time?, les say for portrait, and let say that I use two lights one with f22 and other with f16 and time 1/125 (shooting condition only as example, not real condition, I am interesting in learning how practically to using the rule, not for one time shooting advice asking). Some guidance, please.
The basis of this principle derives from two facts--
1. If you don't use enough exposure to get the shadow detail on film, no amount of chemical manipulation will get that information back.
2. As you increase development time or temperature, highlight density increases much more quickly than shadow density. So much so that for practical purposes, you can consider the shadow density to remain almost constant, whatever the development time. This also means that you can't really increase film speed by increasing development time, as is commonly believed.
This means that you should test your film and developer to see how much exposure you need to record sufficient shadow density in any given situation, and you can test the effect of development time to determine how much development you need to produce detail in the highlights for your printing process in any given lighting situation.
There are a number of ways to determine the amount of contrast in any given scene. I prefer the Zone system described in Ansel Adams' _The Negative_, which uses spot metering. Some prefer to use incident metering, as described in _Beyond the Zone System_, and there are other approaches as well.
This is mainly aimed at photographers using natural light.
The situation you are describing is a studio situation. In the studio, I don't use the Zone System to determine development time, because it is possible to control the contrast of the scene directly by controlling the light, so I use an incident meter with a diffusion dome, control the light ratio by controlling the output and position of the lights, and always develop for "normal" contrast.
I had problems with this too (despite having it explained to me by a lot of very patient people) until I read John Blakemore's darkroom workshop book.
The destination is important, but so is the journey
Exposure is the key to recording sufficient detail in the shadows and film development provides the contrast control and density of the highlights. I will break down the saying " expose for the shadows and develop for the shadows" as follows:
To understand the logic of what I am about to describe you must understand how all meters work. They are calibrated to 18% mid grey, therefore whatever you take a meter reading from will be rendered as mid grey in the print unless you make the necessary adjustment to the exposure you use. Because shadows are generally darker than mid grey it is necessary to adjust the reading given by the camera. Some photographers place all landscape shadows on Zone III which is TWO stops less than mid grey but some, including me, place landscape shadows on Zone IV which is ONE stop less than mid grey. The choice is yours, I would suggest that you try both and use what suits your taste.
In order to record shadow detail you need to accurately meter the darkest shadow and adjust the metered reading down by ONE or TWO stops. For example, if the meter reads 1/60th @ f11 you would expose at either 1/125th or 1/250th both at f11 to expose correctly to record detail in the shadows.
The next step is to determine the range of contrast in the subject you are photographing, for this will determine how you will develop the film. My rule is that if the contrast range is below 3 stops I will underexpose the film by one stop, after I have adjusted for the shadow exposure as described above, and increase film development by 25% which equals ONE stop or even by twice 25% which equals TWO stops.
If the range of contrast is 3 to 5 stops I will develop the film normally. If the range of contrast is greater than 5 stops I will increase exposure and reduce development but opposite to the description given for a low range of contrast.
More development means higher contrast and less development means lower contrast.
To calculate increased or reduced development the following will help:
Assume that normal development is 10 minutes. To increase by ONE stop calculate 25% of 10 minutes which is 2.5 minutes therefore the adjusted devleopment time will be 12 mins 30 seconds. To increase by TWO stops the calculation must be done in two steps. First calculate the increase for ONE stop as above and then calculate for TWO stops by starting with 12 mins 30 secs as the development time, 25% is 3 mins 15 seconds therefore the development time for an increase of TWO stops will be 15mins 45 secs. To calculate reduced development you would deduct 2mins 30 secs from 10 mins giving a time of 7 mins 30 secs for ONE stop. 25% of 7 mins 30 secs is approx 1 min 45 secs therefore the development time for a TWO stop reduction in development would be 5 mins 45 secs.
I hope this helps and is not too complicated to understand, if you need further explanation please PM me and I'll be happy to help further.
Originally Posted by Les McLean
I recently got Les' book "creative black+white photography" and he has excellent examples of what he describes here, Not to mention a very large amount of other awesome information.
"The negative is the equivalent of the composer's score, and the print the performance." ~Ansel Adams
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Thank you all for fast and detailed informations.
Les, if I remember correctly, I belive you wrote same (or simillar) explanation like this in Practical Photography magazine few years ago, and I remembered it only when read it again now. And I understood it even then. Of course I know how meter works, and I know that if, for example, I use spot meter metering shadows, I must compensate (use faster shutter speed) for getting correct exposure. What I didn't understand was part of developing. But, I do understand now practical using of mentioned rule, and now go to practice.
Well as I use roll film (120 and 35mm), not single shhet films, I belive this will be more difficult to do, but I will try fo figure out how.
And, Les, don't be afraid, if I ever need it, I will be so selfish to use your generous offer
Yep, I'll very happily recommend that book too!
Originally Posted by panchromatic
Worth the price purely for the case studies. The other ton-and-a-half of indispensable information comes as a bonus...
The destination is important, but so is the journey
The book is a must have and as you can see, Les is an excellent teacher.
And that is also thing which I never understood.
Originally Posted by David A. Goldfarb
I know that I can use for example ISO100 film as ISO200 and then change developing time acording to change of film speed (in fact using slower film as faster film). Or to use ISO100 as for example ISO50 film. That I know, and I did that.
For example in box of EFKE ISO100 film is written that under tungsten light obtained speed is ISO50, and under flash lights obtained speed is ISO100. Is that means that under tungsten lights I must to use that film as ISO50 film (set my meter for using ISO50 film)?
But I never understood what means using ISO100 film as ISO100 and "changing its speed" with development? I read about it, but I don't understand concept of using film at its native speed, and obtaining different speed with developing. What is reason for that
Is using ISO100 film as ISO200, and changing developing time acording to that, same as using ISO100 film as ISO100 and increase its speed with developing (even if you David said it is wrong thinking that is possibile, me too don't see logic in that).
Thanks and regards.
Have you done film speed tests with your preferred film/developer/camera(meter) combo? That's the first place to start. Get everything calibrated and then start changing stuff.
Originally Posted by haris
Somewhere on these forums (Im at work and dont have it bookmarked) is a pair of articles that explains this to the nth degree.