contrast question

[cypilk]

when you take a picture..and in the frame, there is a part of real bright light and another part of the frame with real dark,...how do you go about taking the shot, without making the contrast too heavy?..

im saying how do you balance the shot so that neither side is too dark or too light?

 

[TheProf]

Well there are a number of things you can do.

1. meter both areas and average the two. This will work ok, better than taking a straight reading.

2. Meter your shadow and under expose by 2 stops. This is a partical Zone system technique and should give you a decent result if the diffrence between your highlight and shadow is not to great. Basically your placing your shadow in Zone 3. 5 is middle gray and that what your camera meter is set to. By putting it in zone 3 you are placing it in a Zone where it is dark but still showing shadow detail. this will also under expose your highlights so that they will not be blown out.(I think i got that right)


The true way of doing it is to mesure your hightlight and shadow and count the stops, a normal rage should be 7 if it is above say 9 then it it normal +2 you whould then meter like sterp 2 and then you would adjust your development time (assuming you doing B&W) to a Normal+2 time for your specific film/developer combination. This will give you a rage of 7.
If you want to try this and your developing yourself I would suggest getting a Zone System book that has dev times in it. I think there is an equasion for this but I dont know it off hand.

Sorry if this dosnt make sense.

 

[ksmattfish]

The true way of doing it is to mesure your hightlight and shadow and count the stops, a normal rage should be 7 if it is above say 9 then it it normal +2 you whould then meter like sterp 2 and then you would adjust your development time (assuming you doing B&W) to a Normal+2 time for your specific film/developer combination. This will give you a rage of 7.
If you want to try this and your developing yourself I would suggest getting a Zone System book that has dev times in it. I think there is an equasion for this but I dont know it off hand.

With BW film if you want full shadow detail and full highlight detail then the tonal range between highlight and shadow can't be more than 5 stops. Beyond 2 stops from middle gray in either direction you will begin to lose detail.

Color film, slide film, and digital have even less range, although I'm not up on the specifics. For digital you could take two exposures, one for the highlights and one for the shadows, and then merge them in PS. For slides you just have to get the right lighting ( or do like the digital above and scan them).

For BW film I'd measure the important highlight detail and measure the important shadow detail, and count the stops between. For 3 stops difference under expose 2 stops from middle gray and over develop +100% time. For 4 stops under expose 1 stop, and increase dev time by +50%, 5 stops no change, 6 stops over expose 1 stop and under develop -25%, 7 stops over expose 2 stops and under develop -50%. These are very general time adjustments, and really you should do film tests to determine your exact needs. Check out Henry Horenstein's book "Black and White Photography; A Basic Manual".

 

[TheProf]

Thanks for clearing up my rambilings matt Been awhile for the Z system

 

[cypilk]

For BW film I'd measure the important highlight detail and measure the important shadow detail, and count the stops between. For 3 stops difference under expose 2 stops from middle gray and over develop +100% time. For 4 stops under expose 1 stop, and increase dev time by +50%, 5 stops no change, 6 stops over expose 1 stop and under develop -25%, 7 stops over expose 2 stops and under develop -50%. These are very general time adjustments, and really you should do film tests to determine your exact needs. Check out Henry Horenstein's book "Black and White Photography; A Basic Manual".

wow..that seems very confusing.. .what does you mean when u say.. stops... like aperture stops?.. point the camera to a dark spot...and not the f/ and then point to the light spot and note the f/ and then take the difference?.. and from that... u underexpose or overexpose..and then push or pull the film?..

what's dev time?

 

[ksmattfish]

Thanks for clearing up my rambilings matt Been awhile for the Z system

Well, I was thinking about this later, and I realized that when I say 5 stops of complete detail that's refering to a final, enlarged print. The film itself probably is cabable of recording 7 zones of full detail. Some people claim they can get up to 9. But I've always been taught not to count on more than 5 zones of full detail in a BW print.

 

[ksmattfish]

For BW film I'd measure the important highlight detail and measure the important shadow detail, and count the stops between. For 3 stops difference under expose 2 stops from middle gray and over develop +100% time. For 4 stops under expose 1 stop, and increase dev time by +50%, 5 stops no change, 6 stops over expose 1 stop and under develop -25%, 7 stops over expose 2 stops and under develop -50%. These are very general time adjustments, and really you should do film tests to determine your exact needs. Check out Henry Horenstein's book "Black and White Photography; A Basic Manual".

wow..that seems very confusing.. .what does you mean when u say.. stops... like aperture stops?.. point the camera to a dark spot...and not the f/ and then point to the light spot and note the f/ and then take the difference?.. and from that... u underexpose or overexpose..and then push or pull the film?..

what's dev time?

It's confusing because you are unfamiliar with the terms I am using. Pick up the book I recommended; I saw it yesterday in a used book store for $3.

A stop is a doubling or halfing of the amount of light.

Going from f/4 to f/5.6 is reducing exposure 1 stop. Going from f/8 to f/4 is increasing exposure 2 stops (f/8 to f/5.6 to f/4). Going from 1/60th sec to 1/125th sec is reducing exposure 1 stop. Going from 1/250th to 1/30th is increasing exposure by 3 stops (1/250 to 1/125 to 1/60 to 1/30). ISO 100 film is 2 stops slower than ISO 400 film. ISO 800 is 4 stops faster than ISO 50 film ( 50 to 100 to 200 to 400 to 800). Aperture, shutter, and film speed are your main controls, and if you understand that they are measured in stops (doubling or halfing the amount of light), then you can see how they can be used together to get different results even in the same lighting situations.

When I am metering a scene, I use a spot meter to measure the correct exposure for the shadows with important detail I want to make sure I get. Then I measure the highlights with important detail I want to get. Then I am counting the stops between these. If you don't have a spot meter (your in camera meter can be used much like a spot meter, even if it doesn't have that specific function), then get close to where you are metering, or meter an area that has the same lighting.

So on a sunny day if I measure a gray card in the sun it says proper exposure is f/16 @ 1/125th @ ISO 100. Then I measure the grass in the shadow of a tree and it says f/4 @ 1/125th @ ISO 100. Then I measure the edge of a cloud and it says f/45 @ 1/125th @ ISO 100. Remember, the meter is giving you the exposure to expose these and come up with middle gray, but we don't want middle gray, we want dark shadows and bright clouds. So I count the difference between f/4 and f/45: 4 - 5.6 - 8 - 11 - 16 - 22 - 32 - 45. There are 7 stops difference. It's a very contrasty day.

My BW paper will not handle 7 stops with full detail. I have to contract the tonal range down to 5 stops. So I overexpose the film 2 stops (f/8 @ 1/125th @ ISO 100), and then I decrease development time (the time the film should spend in the developer) by half (decreasing dev time reduces contrast, increasing dev time increases contrast). Of course, if I am using roll film, then I need the entire roll to be shot in lighting conditions that require a 50% decrease in development time.

On an overcast day I get a general reading of f/5.6 @ 1/125th @ ISO 100. My shadow reading is f/4 @ 1/125th @ ISO 100, and my highlight reading is f/11 @ 1/125th @ ISO 100. Count the stops between f/4 and f/11 and you get 3 stops: 4 - 5.6 - 8 - 11. A low contrast lighting situation, so this time I want to expand my tonal range of full detail to 5 stops. To do this I will underexpose by 2 stops ( f/11 @ 1/125th @ ISO 100), and increase development time by 100% (or double it).

There are tones of light and dark beyond the 5 stops I am dealing with, but they will not have 100% detail; it begins to get lost in the light and dark. As long as I make sure that the important stuff is covered, then i can sort of let the other tones fall into place.

Now, keep in mind that with neg film (print film) it is much easier to get into trouble underexposing than overexposing. If you underexpose too much, and lose the shadow detail, it's gone forever. If you block out highlight detail with overexposure, most of the time it can still be burned in on the print.

Also my recommendations for altering the development time are just very general approximations, and must be individually determined for different films, equipment, chemistry, and even photographers. For instance T-grain films (Tmax and Delta) respond much more quickly to changes in development times, so they shouldn't be changed as much.

I know it seems complicated, because I can still remember when I felt that way, but now here I am rattling this stuff off the top of my head as i type. Just try to grasp one concept at a time (what is a stop, and how do aperture, shutter, film speed, etc... work together is a good place to start), and before you know it it'll seem old hat. It rally is much simpler than it seems, it just may need time to sink in. Good luck!