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Creating images in the lab .. How to process images .. Photography book

How to process images
Creating images in the lab

- Low prominence:
When a negative and a transparent positive of the same dimensions are placed and represent the same subject in the magnifier with a slight neutralization between them, we get a false prominence also called. Low prominence Parlanev (in which the subjects appear separated from the background). This effect is easy to observe in large-sized clichés, for example 9 x 12 cm - and the degree of neutrality required depends on the size. The negative and the positive must have approximately the same density and contrast. This can be done from different subjects, either subjects representing large uniform areas or, on the contrary, very detailed subjects. In the latter case, it is sometimes difficult to recognize small details.

- Isoheli:
This technique involves converting the intermediate gradations of a normal negative into a set of areas, each of which has a monochromatic density. Usually, you get three or four values, starting from white to black. We achieve this by achieving a certain number. From the positive images we choose its color degree. Two of them are required for an isohybrid with three values ​​and three images are required for four color degrees.

The negative with intermediate tones is drawn onto sheets of film (light) which are then processed in the appearance of (light), obtaining a transparent positive with great contrast. The density of the positive images depends on the exposure given to each of them. The subject is then represented by shadows of different densities on each positive. The positive image that you have chosen for high lights is exposed for a longer period of time, which turns the shadows and half-tones into an opaque mass: only the high lights remain transparent. The positive image with half-tones is then exposed so that the shadows and half-tones of the darkest colors become black on the film. The half-tones and the high lights are transparent. Finally, the positive image that you have chosen for shadows, exposed for a shorter period than the previous images, is opaque only in the shadows. Each of these positive images will be drawn in succession onto negative film with intermediate tones. The first positive film print should give a light gray density. When a prior experiment allows this density to be obtained, the other two positive images are successively drawn on the same film with exactly the same exposure time. The result is a negative image containing four values ​​of color tones including white. The greatest difficulty lies in recognizing during successive exposures the three positive images on the same film: a recognition and focusing device must be provided and, on the other hand, all the magnifier calibrations must be constant throughout the entire duration of the operations.

- Sabatier effect (quasi-solarization):
To obtain this effect, a printed and partially developed negative image must be re-exposed to white light. Then the development process is continued according to the manufacturer's usual data. The result is a partial or complete reversal of some of the image densities, i.e. a mixture of negative and positive on the same film.

To obtain this effect, prior experiments are required by research. But here are some instructions for starting: Stop the development in two-thirds of its full duration and expose the film (at normal speed) for twenty seconds under a 25-watt lamp. This is only the basis for a first experiment and you will undoubtedly have to modify it to achieve the desired effect because. This is due to factors that cannot be controlled and if you want a complete inversion of the values ​​of the negative image less clearly stop the development before that time. Complete inversion of the values ​​of the negative image requires intensive exposure: in practice this inversion is very difficult to achieve.

The same method can be applied to positive images and according to the same principles. Stop the development after half the normal time and expose the images to white light for ten seconds and then complete the development.

- Exaggeration of details:
The effect of the low-relief engraving method transformed this very ordinary image into an image with a beautiful repulsion. This treatment is suitable for all images that contain very visible lines. The effect of the semi-relief depends above all on the importance of the lateral neutralization between the negative and the positive image. For this example, I directly drew the negative by contact on the gradation medium film and this gave me a positive image with the same contrast but lighter than the negative. Then I superimposed the negative and the positive image, this process is called a sandwich with a slight neutralization, and then drew the image on it.

- Giving a certain atmosphere:

You can modify the atmosphere of your photo in the news. The landscape on the opposite page was taken on a gray day, so the conditions did not suit the characteristics of the subject. I started by sticking a piece of transparent tape on the sun visor in the lens, which lightened the middle part of the photo. The rest of the transformation was done in the lab. Towards the end of the exposure of the enlarged image, I turned on the metabolism: This led to the light partially flipping in the values ​​of the photo. Then I continued the exposure by wiping the appearance with a piece of cotton on the photo in order to give these dark values ​​distributed irregularly, especially in the sky.

- Flattening the values:
Isoheli is a method that allows you to transform a normal photo with intermediate gradations into, for example: a photo with a few gradations. Black. Dark gray, light gray and white, as in this photo. The main negative is printed on three pieces of high-contrast film called light: the first piece is underexposed, the second piece is exposed normally, and the third piece is overexposed. Then these three wave films are drawn with similar exposure and thus on a single piece of film with intermediate gradations the images must be well and completely overlaid and then this mother negative is drawn in the normal way.

- Removing intermediate tones:
This method allows a normal image to be transformed into an image with very clear lines. The growth of contrast hides all the intermediate values ​​that exist between black and white. I enlarged the negative image on paper and exposed it in a high contrast detector. It was not enough contrast. I photographed the image again and pulled out the negative image that I obtained.