صنع الطبعات الفوتوغرافية ١-a .. كتاب طبع وتحميض الصور الفوتوغرافية

the fourth chapter

Making photographic prints

Printing photos at home is the cheapest, as it costs almost nothing when compared to the costs of sending the film to the development laboratories. In addition, you can control your photographic work and produce it in the best way, which is not available in development laboratories due to the nature of their commercial work and the large amount of films that they print at one time.

photographic edition:

It is simply a positive image inverted from the negative (negative) printed on photosensitive paper. It is made by exposing the sensitive paper to the light of a magnifier shining on it from a negative placed in a carrier between it and the printing paper. An image formed on photosensitive paper is called a photographic print. The image formed on a photographic slide is called transparency (slide).

Zoom Edition:

This is done by Magnifier Enlarger and Magnifier is a device that enlarges a negative image

offered on demand. Thus, we can make large prints of the negatives, whatever their size. It is noticeable that the larger the size of the print that we make, the greater the clarity of the grains in it. The smaller the size of the print we make, the less clear the grains are.

Another benefit of the enlarger is controlling the content of prints by deleting part of the negative when printing, and then compensating for this part by increasing the size of the print. However, this work has its drawbacks, as we shall see later.

The magnifier allows large prints to be made of small negatives.

camera and magnifier

The magnifier can be considered an inverted camera because the camera is a tool for minimizing large sizes in nature and converting them into small sizes recorded on the negative inside. As for the magnifier, it enlarges the image of the negative that it displays to the size we want. In the following, we will review some of the optical characteristics of the camera and magnifier in order to understand the work of the magnifier well and thus achieve maximum benefit from it.

convex lens:

The convex lens is the most common lens in imaging, and if we look at it from the side, it appears to us that it is thicker in the middle than on the edges. All lenses have the property of refracting the light passing through them in varying shapes and degrees. But for a convex lens
Distinctive properties, including:

1- If we place a flat surface behind the convex lens and light rays coming from a distant object pass through it, a shape similar to the distant body will be formed on the flat surface. And we say that the image of the object has been centered by the lens on the flat surface that we call the focal plane

2- The distance between the center of the lens and the focal surface is called the focal distance. 3- If we put another convex lens at the focal point instead of the flat surface, the light passing through it will not gather to form an image, but rather it will deviate, forming a straight ray. This is the principle of the lens used in modern cameras, where a beam of straight light rays falls on a film slide forming the photographic image.

A convex lens is thicker in the center than at the edges.

In the early days of photography, a single convex lens was used in cameras. But now several lenses are used, and we call the group a short name

the lens.

The depth of field of the lens in the camera is symbolized by numbers usually engraved on the front of its cylinder. These numbers are valid only when forming well-focused images of objects at infinity. More than 30m away from the camera. The closer the subject is to the camera, the more it is

Camera A focused on a subject at infinity. When the subject got closer to Camera B, we noticed that the lens was pulled out a bit in order to secure a correct focus for it.

focal length. This means that in order to keep the image of the object on the focal surface (film slide here) the lens must be moved slightly away from the camera. This is exactly what it does automatically when you focus the image image through the viewfinder of the camera. You are in

This condition increases the focal length of the lens for objects closer to the lens than infinity. Cameras from the factory usually come equipped with what are called "Normal" lenses. And the regular lens enables you to see the same section of the scene that you can watch normally, that is, without changing its dimensions, whether in terms of distance, proximity, or in terms of its wide angle, because it can focus on subjects that are very close to the camera, and on subjects that are far from it as well. It is considered a good choice for general uses in photography. Lenses with a focal length shorter than the normal length include a larger portion of the scene than what is included in the normal lens, and for this reason it is called a wide-angle lens, and it is useful for photographing wide landscapes and photographing buildings, because it includes a large part of the scene.

Lenses with a focal length longer than the normal length magnify the image. Therefore, it will include a smaller part of the scene than what is included in the normal lens, for example, the telephoto lens, which is useful when photographing distant subjects. The foreground and background will look blurry, i.e. out of focus.

completely. The amount of objects close to a sharp object that will also appear sharp depends on the depth of field of your camera. As the intensity or weakness of the depth of field depends on the aperture of the lens and its depth of field. As a general rule, remember that the larger you get, this is not true.

Note the effect of depth of field on image sharpness. The left photo was taken with an aperture of f / 2 / between which the right photo was taken with an aperture of f / 16 and from the same place. We note that the aperture of the lens has a clear effect on the depth of field.