Meeting 11

One print due at the beginning of class. Critique of work.

Pushing and pulling film
Handouts are here.

Pushing is the term usually used to identify film that has been purposefully underexposed and then developed longer. Film developed longer will have significantly denser highlights when compared to a normally developed roll or sheet. Shadow density will increase a small amount, but not nearly as much as the highlights. Because the density range of the negative increases, contrast in the print will be greater. Pushing is often done to sacrifice shadow detail for a faster shutter speed in critical situations where print quality is secondary to capturing fleeting content.

Pulling film has the reverse effect. Film that has been exposed more and developed less than normal will have more shadow density (shadow detail), and reduced highlight density when compared to normally exposed and processed film. Contrast is lowered. Pulled film use on contrasty days helps tame excessively deep shadows combined with very bright highlights that otherwise threaten to print as bald white.

It is important to separate the effect of exposure and of development when thinking about pushed or pulled film. Increased exposure is NOT the same as increased development, although both will produce denser negatives. The old adage "Expose for the shadow, develop for the highlights" is a good statement to help explain the differences. Experienced photographers know that shadows must be exposed well enough to print with open detail, and they also know that development should be tailored to produce highlights that print with acceptable tone.

Increased exposure will increase negative density in both shadows and in highlights.

Increased development will produce denser highlights in the negative, but has only a small effect on shadows.

Below is a "ring-around" that shows combinations of underexposed, normally exposed, and overexposed film combined with underdevelopment, normal development, and overdevelopment. Note that terms like "over exposed" suggest it has deviated from proper exposure, but the scene brightness range may actually require more exposure to capture important  shadow information.

These Tri-X negatives are mounted in slide mounts and were photographed together on a light table. Markings on the slide mounts indicate what combination of exposure and development was used. The "normal"  negative is in the middle. A notation of "-3" indicates the film received three stop less light than the exposure meter suggested. For developing time, you can see notations of "200%" or "x2" which mean the film was developed twice as long as normal.

I don't recall what ISO setting I used for the "Normal" Tri-X exposure, but I would assume I used ISO 200 like I've done for over 25 years.

Notice how exposure is the most significant determining factor for density in the very deep shadows, and developing time changes affect mostly the highlights.

Here are some scans of prints showing the difference between prints made with pushed and pulled film:

Note the difference in how grass is rendered, and the shadow detail in dark areas (tree trunk and shaded side of jeans) between the two examples. There is a pure black in each print, but you will go deeper into the shadows for it in the print made from pulled film.

An important conclusion you can draw from this is:

If you underexpose your negative, increasing your film developing time will NOT put significant shadow detail back into the deep shadows.

Another important conclusion:

If you push film (underexpose and overdevelop) to obtain higher contrast, you CANNOT reduce the contrast enough to match that of a normally made negative. The shadows will often look weak and gray if you try.

By comparison, you can pull film, and later add contrast when printing to get close to the contrast of pushed film.

It's easy to add contrast to a picture, but you might not be able to reduce contrast and still make an acceptable print. This is true in digital capture just as it is with traditional methods.

What the Zone System is
Handout

View camera discussion

Bradford Washington's Mountain Photographs portfolio.