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Controlled exposure .. How to process images .. Book of photography

How to process images
Controlled exposure

The different exposure times specified during the experiments should lead to a good quality of the enlargement. However, some negatives require special treatment during the exposure to show this or that area of ​​the image that would otherwise be too light or too dense. For other images, you may want to interpret the image by giving it a stronger or lighter intended contrast than usual, or you may want to achieve a decorative frame.

We can vary the exposure of the image locally by covering some areas during a portion of the full exposure time. By intercepting the light beam coming from the enlarger for a specific time on a specific area using your hand or a piece of opaque cardboard, you open up this area. Conversely, you can increase the local density by extending - that is - the exposure time on the area you choose. This means that we can - optionally - give the desired value to each of the important parts that make up an image. This special process is called the makeup process: This makeup requires good experience in the art of magnification, it is a method that you must master completely if you want to get magnified images with high qualities.

Apart from this makeup process, there are other manual treatments and methods that you can do and practice during magnification: for example, softening the image by placing it under the lens or pulling the image with light or dark values. You can also expose the image through any transparent element that contains geometric or irregular subjects.

- Oily or decorative frames:
The background or bottom of the decorative frame can be white or black with a slight modification in the method. To get a white bottom, cut out a geometric shape from a piece of cardboard with dimensions slightly smaller than the dimensions of the image. Hold this piece and place it in the light beam that the magnifier transmits during the entire exposure period. As for a dark-colored frame, on the contrary, you hold the middle section of the cutout and place it in the light beam during a second exposure in order to protect the useful area of ​​the image.

For a decorative frame with a white bottom, use a cardboard screen.

For a black decorative frame, use a double exposure using a cardboard screen.

Here is a picture with a white border.

A decorative frame with a black bottom.

- Makeup during zooming:

If we use a veil with clear edges to block an area of ​​the image, we will find on this image the boundaries of the sections on which makeup was applied. To reduce this, move slowly but without stopping the eyebrow, which should be smaller than the section on which makeup is to be applied. Some photographers use their hand as a veil, but in many cases, let you have makeup tools made of cardboard to help you do more precise work.

To lighten an important area of ​​the image, move your hand slowly during a period of full exposure time.

To lighten a small area, use a small cardboard veil fixed to an iron wire and the veil has the shape of the area you want to block the light from.

To increase the density of an area, expose it again while blocking the areas that were sufficiently exposed to light with your hands.

If the area to be shaded is small and specific, pass a piece of cardboard with a small hole perforated over the area that needs makeup.

- Weak and strong contrast: All negatives must be printed on suitable paper, the contrast values ​​can be known from the numbers recorded on the cardboard cover of the paper, 0, 1 and 2 are papers for soft printing and enlargement, 3 is normal, 4 and 5 are hard and very hard. Sometimes, to give a decisive effect, an unnatural contrast can be chosen. A soft image gives us reasonable tonal gradations (above), a hard contrast image with clear whites and dense blacks (to the right), (above right) the natural image used for comparison. Certainly some negatives are more adapted than others to this adjustment, the normal contrast adjustment.