How to get contrast?

[zdav]

Here's another how-to question for you guys.

How can you control the level of contrast in an image?
Is there anything you can do to control this at the time you take the picture? I understand that the level of contrast is mainly the result of the available light that shines on the scene.

What else influences the amount of contrast? Exposure? Type of film? Iso? Or is this mainly influenced during the developement process?

thanks,

Staf

I don't know if this makes a difference but I'm mainly interested in b/w photography

 

[Juan Valdenebro]

Do you want more or less?

For the same scene, different kinds of light, or ND filters, or different films or digital camera settings, then development, printing, toning...

Cheers,

Juan

 

[zdav]

hi Juan,

I would like to have more contrast. To reduce the level of variables: I'm just an amateur shooting film, so no digital camera, extra studio lights. I have my films developed / scanned in a shop.

tnx,

Staf

 

[Pickett Wilson]

Different film has different contrast characteristics. You can use fill-flash to lower contrast ratios when shooting people close up. And black and white paper is available in various contrast levels - or you can use variable contrast paper and control the contrast range with filters in the enlarger. And contrast can be controlled by varying film development times.

Contrast can be modified to one degree or another at every stage in the photography process.

 

[Roger Hicks]

More development = more contrast (and more effective film speed)
Less development = less contrast (and reduced effective film speed, thoiugh not as reduced as you might expect).

Slow films build contrast faster with more development; fast films build contrast slower.

The concept of gamma (density vs. exposure) is essential here: see http://www.rogerandfrances.com/subscription/ps neg density.html

Cheers,

R.

 

[hans voralberg]

Roger you mean fast film build contrast slower right?

 

[Juan Valdenebro]

If you just print after scans, treat contrast digitally.


If you need more contrast on negatives for real printing, allow less light in, and develop for longer times with D76 or ID11, or Rodinal. And use higher contrast filters when enlarging on multigrade paper.


For slide film there's less margin, just pushing a bit: not as much as with B&W...


If you find your scans or prints flat, I guess you shot on soft light, maybe overcast or in the shadows... Look for strong direct light producing rough shadows... Then you won't need to develop for much time, and you'd better expose for a good amount of light reaching the film.


Then, place textured subjects with light coming from the sides, not from the front...


Cheers,


Juan

 

[HMFriedman]

Use slower films at higher ISO ratings to reduce shadow detail, and have your film developed for longer periods of time, with more agitation. You should probably be developing your own film, to get what you really want.

Be careful with this; in my experience, printing high contrast negatives is a bear. But then, I like my mid-tones.

 

[Roger Hicks]

Roger you mean fast film build contrast slower right?

Sorry; yes; amended.

Thanks,

R.

 

[Steve M.]

Different films will give different amounts of contrast. But no matter what film you use the key is to get correct exposure. Bracket some shots to see at which setting your best shots are at. Are you shooting B&W? Using a yellow filter will bump up your contrast nicely and improve your skies.

 

[zdav]

Thanks for the replies so far, very helpfull. I guess I have some reading / experimenting to do to fully understand but you guys definitely got me started.

 

[Roger Hicks]

Consider getting a copy of "The Negative" which is part of Ansel Adams' three part series on photography.

Study the Zone System and you will understand contrast and the relationship between exposure and development.

As Roger said: Less exposure and compensating overdevelopment will increase contrast while more exposure and compensating underdevelopment will decrease contrast.

There are other methods, after the fact, such as using a contrastier paper or bumping a slider in post production software such as PhotoShop.

(On the Zone System): yes, but be aware that some people find the books unnecessarily hard to read. The Zone System is a subset of sensitometry, and there may be other books that some people find more congenial, such as Dunn and Wakefield's Exposure Meters and Practical Exposure Control. Hard to find, but a lot more readable as far as I am concerned.

In other words, if you get on with the Zone System, great. If you don't, ignore it without a backward glance and don't think you're being stupid, ignorant, etc., or that the subject is too difficult to understand. It isn't.

Cheers,

Roger

 

[Roger Hicks]

Experimenting is essential in this process of contrast control.

The essence of the Zone System is to moderate exposure and development to ideally achieve a negative to print on #2 paper. As such if there is a need to further moderate contrast there are grades above and below that may be selected.

Filters can also be used to increase contrast in a scene by selectively filtering certain colors to alter their ratio to others in the image. As such the use of yellow, orange or red filters, progressively, will reduce the amount of blue in the area of the sky thus increasing the contrast with white clouds or green mountains.

I have always believed that to really understand the photographic process one should shoot and develop their own film, and then print it. Nothing illustrates these concepts quite like seeing them work in your own hands.
.

I could not agree more, especially with the highlighted part.

The OP may also find this useful, from http://www.rogerandfrances.com/subscription/ps neg density.html

. . . 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.

Actually, I'd add that anything after 1, and possibly 1 itself, can be ascertained by personal experience, as you suggest. The concepts in the list are dealt with earlier in the module: ISO(R), in particular, is a measure of paper contrast, ranging from around 40 (grade 5) to 180 or more (grade 00). Using ISO(R) frees you from having to compare different manufacturers' grades, where the same contrast may be called grade 2 by one and grade 3 by another.

Cheers,

R.