"Expose for Shadows, Develop for Highlights"

[raytoei@gmail.com]

Roger,

I come across this phrase quite often, and I would like your opinion of what it means.

My understanding is that exposure controls shadow details, and development controls contrasts.

So for example, if i were to shoot with Tri-x 400, and expose at 320iso, then there are more details being captured at this 320 iso, within the constraints of the film. Conversely, if I were to "push" the film, ie. underexpose it by say 2 stops at 1600, then shadow details tend to be lost.

In the development area, an increase in development time will increase contrast.

thanks!
raytoei

 

[Roger Hicks]

You are right.

First, you need to give enough exposure to ensure detail in the darkest area in which you want detail. This does not need to be the darkest area in the picture: you can let that go black if you want. This is 'exposing for the shadows'.

The only sure way to give the required exposure, no more (which will reduce sharpness and increase grain) and no less (which will lose detail) is to meter the shadows directly. This means going up close with an ordinary meter, but with a spot meter, the narrower the angle, the further away you can be when you read.

You do NOT use the main index on the meter -- in fact, there is little or no reason for a 'mid-tone' index on a true spot meter -- but the 'shadow' index, I.R.E. 1 or similar, typically 2-1/2 to 3 stops down from the 'mid-tone'. If there is only a mid-tone index, go 3 stops down.

Next, you consider the subject brightness range (SBR). Read the brightest highlight in which you want detail. If it's 5-7 stops brighter than the darkest shadow, it's an 'average' subject and requires 'average' development. If it's under 4 stops (highlights dim compared with shadows) give 50% extra development time to increase contrast. If it's over 7 stops (highlights much brighter than shadows), give 15% less to reduce contrast. This is 'developing for the highlights'.

All of these figures are approximations. You may find that you're happier with 2-2/3. 2-1/2, 2-2/3 or even just 2 stops down, instead if 3, if there isn't enough shadow detail. You may be happier with treating 4-6 stops as 'normal' instead of 5-7. You may be happier with 30 or 40 or 60% more dev time instead of 50, or with 10 or 20% instead of 15. You may even decide to do the whole Zone bit, with more than just 'standard', +50% and -15%, though that starts getting interesting with roll film, let alone 35mm, where you have different SBRs on one film.

Alternatively, of course, you can rely on the inherent latitude of pos/neg photography, and on the fact that latitude for overexposure is a stop or two before sharpness falls too far and grain gets too big, especially with larger formats than 35mm. This is what saves a lot of people who think they are being scientific, but (for example) start off with highlight readings.

There's a lot more about this on my site.

Cheers,

R.

 

[Chriscrawfordphoto]

In itself, the phrase doesn't really tell you anything. I suspect that many of the people who say it have no clue what it really means themselves, because you'll see many of them show disdain for exposure and development methods (like the Zone system or Phil Davis's BTZS system) that bring the idea into actual practice.

I expose using a spot meter. If there's something black or heavily shaded that i want to retain detail in, I meter it and give 2 stops less exposure than the meter says. Then I point the meter at a white or highlight araa, if there is one in the scene and it should meter about 4-5 stops brighter than the exposure you set on the dark area if you want full detail retained in that white area. If it meters higher than that, you reduce developing by 25% and give one stop more exposure. The reduced developing time lowers contrast and because the reduced dev. time lowers the film's effective speed one stop, we give the extra stop exposure too. I virtually never see a time when one must increase contrast, not in the lighting conditions where I live. Much more common to need to reduce it.

 

[charjohncarter]

I don't know anything about 'push' but develop time also is very important in controlling highlights from blowing. In my case (roll film), like above, I set the shadows (or expose for the shadows)(there are a few ways to do this) and then develop my roll of film, as I have determined from previous developments; so, on average, highlight will not be blown.

 

[ChrisN]

One of the most useful articles I've read on the subject and its application to roll-film cameras: Mike Johnston's Not Much of a System System.

 

[erik]

The phrase has been around a long time. I found a reference to it in a manual from 1908, before meters were in wide use. The way they described it: look at your scene and describe the quality of the shadows, such as hard edged or diffuse, then choose an appropriate exposure time based on that. They offer some advice based on the sensitivity of the plate one is using. Then, develop the plate (this is back when develop by inspection was commonly done) until the highlights look right. How does one know what is "right"? Experience mainly.
100+ year old advice, probably not too useful today.

 

[charjohncarter]

The phrase has been around a long time. I found a reference to it in a manual from 1908, before meters were in wide use. The way they described it: look at your scene and describe the quality of the shadows, such as hard edged or diffuse, then choose an appropriate exposure time based on that. They offer some advice based on the sensitivity of the plate one is using. Then, develop the plate (this is back when develop by inspection was commonly done) until the highlights look right. How does one know what is "right"? Experience mainly.
100+ year old advice, probably not too useful today.

Well, at least they were developing in real time for the highlights. I still do the same with roll film but I have to shoot a whole roll and develop. Then I wait for it to dry and process one way or the other. And finally I see if I did it right. By that time, I have forgotten what I exposed for and what ISO (EI) I used, or was my metering right, and if I developed exactly the same as the last try. Notes are great but somehow I have to guess at them too. Thank goodness, film is forgiving, and we still have experts to guide us.

 

[gns]

I think it is easier to get if you first understand what a characteristic (D log E) curve shows. Compare curves of the same film/developer, but with the exposure and development time altered and you get a good visual that makes this very clear.

Cheers,
Gary

 

[charjohncarter]

Some say: put your Zone III on the curve so it is on the upslope of the curve, but that is at box speed; generally. Others reduce their box speed which puts Zone III on the upslope of the curve: which is Zone IV for the first group. But what, I think it boils down to is pick which way you want to meter and do it. And then develop to your highlight taste. Roll film (multiple scene variance) will always be difficult but we have to live with it.

 

[DNG]

I don't know all the science stuff, as some of you do. And it is interesting to read.

I use 1/3 stop overexposure on my meter, and I use a semi-spot meter, and meter for the shadow/mid area... I find an area that contains these values and just use it. Then I develop for the box speed. I use Xtol, I find if I use "Stock" (full strength), I get more contrast, if I want a little less contrast, I use Xtol 1:1. I use the Masters Developers table as my base. I get my temp to 20c/21c and just use the time listed. I agitate every 60c for 15s. And the highlights are always great, and I get great shadow detail also.

Sample from my last roll of Acros 100 @ 64 Xtol 1:1

 

[charjohncarter]

I don't know all the science stuff, as some of you do. And it is interesting to read.

I use 1/3 stop overexposure on my meter, and I use a semi-spot meter, and meter for the shadow/mid area... I find an area that contains these values and just use it. Then I develop for the box speed. I use Xtol, I find if use "Stock" (full strength)

With roll film that is as good as anything. Weston just used to guess. And that was with LF.

 

[gns]

The concept is based on the fact that changing development time has a greater effect on the highlight than it does on the shadows. Longer dev. pushes the highlights up but has little to no effect on the shadows. Likewise, shorter dev. pulls down the highlights without altering the shadows much. Exposure will change the shadows. This what comparing the D log E curves will show you.

So, you set exposure correctly for the shadow areas and then determine dev. time depending on the contrast of the scene.

The zone system is just a sophisticated system for applying this. Many people (like me) use some much simpler approach. If the scene is very contrasty (say, fifth avenue in a strong afternoon sunlight), you want to make sure you give plenty of exposure to get detail in those dark shadows, then cut down the development time to prevent the highlights from getting out of control. Hence a well known street photographers formula is to rate their tr-x at 200 (or even 100) and cut back 30% or more on the development.

Cheers,
Gary

 

[af_]

One of the most useful articles I've read on the subject and its application to roll-film cameras: Mike Johnston's Not Much of a System System.

Thanks for that link, Chris, I have enjoyed reading that.

The main message is:
"Johnston's Not Much of a System System, depends from the following principle: Firstly, get the picture. That is, it's worth it to pay attention mainly to what you're shooting and end up with a decent print of a great shot, as opposed to paying attention to your meters and measurements and end up with a perfect print of a dreadfully boring shot of nothing."

 

[Vics]

Roger, thanks for that very concise and clear explanation! I'm bookmarking this one for future reference. I'll be sure to check your site, too. Thanks also, to the OP for asking this important question.

 

[Juan Valdenebro]

You're right. The phrase is a bit zone system related (all previous to Adams B&W too) and basically talks about giving film enough light for placing the darkest detailed values you need, on zones II-III and and then placing -based upon appropriate development time- your desired detailed highlights on zones VII-VIII (depending on your preferences and how much detail you need), but you need to know well your different development times for the same film to really work the way the phrase describes... For example, you can't do different contrast scenes on the same roll unless you cut it...

I don't like the phrase, by the way, but lots of photographers and teachers do... It can be confusing IMO... Not all scenes have shadows and highlights, to begin with... And shadows and highlights can also be pure black and pure white on print on some photographs and it's not a problem, except for theory fanatics... I prefer to say "expose film for the light it really needs, and develop depending on the scene's contrast." It's not too simple either, because the real (not box) ISO can be great for some scenes, but on a real dark gray, flat day, exposing ISO400 film at 800 instead of 250, for a longer development, produces better tonal separation for dull scenes... And on direct harsh sunlight, metering at 125 for a short development is the way to get rich and clean shadows if the case is we need them... The subject plays a decisive role too, because different subjects are emphasized or thank different final levels of contrast or shadows/highlights detail... All this, related to the quality of light and not to its quantity, is a lot more important than simply metering to "expose for the shadows".

Cheers,

Juan

 

[dyao]

But what happens when you have a bunch of differently lit scenes on the same roll?

 

[Juan Valdenebro]

Some of them will receive better (more appropriate) development than others... Some will be fine and some a bit/too soft or contrasty...

Cheers,

Juan

 

[Chriscrawfordphoto]

But what happens when you have a bunch of differently lit scenes on the same roll?

That's why you own more than one camera body if you shoot 35mm. Some medium format SLRs have a really neat system of interchangeable film backs that can be changed in mid-roll. So, you carry two backs, one for normal developing and one for N-1 (lower contrast developing).

Seriously, when I shoot 35, I shoot the whole roll in the same light and I have extra bodies. For my Olympus SLR system, I have 3 identical OM-4T bodies. One is loaded with my low-light film, Tmax 3200, and the others are loaded with Tri-X (one for normal, one for N-1 developing). For my Leicas I keep normal Tri-X in one bod and the other body I load with either 3200 or N-1 Tri-X as needed. I need a third body...but Leicas cost too much!

 

[gns]

But what happens when you have a bunch of differently lit scenes on the same roll?

Well, obviously you can't get optimal results for all frames.
There will always be some compromise. But knowledge of this stuff will only help you make the best choice.

I think most people shooting 35mm or roll film will shoot enough film (whole rolls) in a given situation that it isn't normally a problem.

Cheers,
Gary

 

[Roger Hicks]

It's not so much advice as a statement of the obvious, once you understand what it means, so it's as valid now as it was when in was first formulated in the 19th century (it goes back well before 1908).

Bear in mind that in those days, most people developed glass plates by inspection. There were however meters in surprisingly widespread use as early as the 1890s: there's a review, and a copy of the instruction book, of a Watkins Bee meter here: http://www.rogerandfrances.com/subscription/w bee.html

Yes, the terms 'shadows' and 'highlights' are confusing until you realize that they are shorthand for 'the darkest area in which you want texture and detail' and 'the lightest area in which you want texture and detail'.

Small decreases in development time (10-20%) have surprisingly little effect on toe speed, because of the way it is defined. For much more on density and the D/lof E curve, see http://www.rogerandfrances.com/subscription/ps neg density.html, which includes the following:

Armed with all this information, it is therefore possible to match just about any subject to just about any paper grade, provided you know the following:

1 Subject brightness range (easily determined with a spot meter)

2 Flare factor for camera and lens

3 Development time for a standard gamma in a given developer

4 Time-gamma curve for the film and developer in use, obtainable by experiment or from the manufacturers

5 ISO(R) of the paper, obtainable from the manufacturer

6 Flare factor for the enlarger and its lens

7 Any personal adjustments you need to make to compensate for your own equipment or working techniques.

In practice, headings 2, 6 and 7 mean that rather than wasting hours on formal experiments it is generally better to rely on trial and error, which eventually becomes consolidated under the heading 'experience', rather than trying to quantify everything.

This is yet another reason why we do not use the Zone System (a free module gives the rest of the reasons). With one camera, one lens and one enlarger it is tedious enough. Add further equipment, and to do it properly, you need to carry out separate tests for each enlarger, camera or lens. In practice, hardly anyone ever does, and they still get good results even when using wildly disparate equipment. This strongly suggests to us that they are deluding themselves about the degree of precision that is either attainable or necessary.

Even so, knowing what happens at each stage and what it means is extremely useful, especially if you want to avoid simplistic or reductionist theories.

Ignore any references to paid or free modules: it's all free now.

Cheers,

R.