لمحة عن فيلم الأسود والأبيض .. كتاب طبع وتحميض الصور الفوتوغرافية

Chapter one

A glimpse of the black and white movie

The process of developing black and white film illustrates the main points in laboratory work in general. It is noted that the successive processes to obtain the final edition, which is the fruit of our tireless work, are closely related, and they include:

1 - The eye

2- The camera

- the film

4- Acidification

e - of course

Camera: It is a machine designed to control the amount of light that falls on the film slide inside it. This is what turns the film into a fixed record of the light falling on it through the lens. Based on this description, the standard camera must contain the characteristics

next :

1- There should be an accurate optical illusion on the film. 2- To show you an accurate optical illusion that is identical to the imagination that will be recorded on the film slide. 3- To adjust the amount of light falling on the film through the lens. The task of the camera is to find an accurate light image that is achieved by the lens and its focal length. The viewfinder in the camera displays an image identical to the image that will be recorded on the camera Film, and the viewfinder system and the way it works differ according to the viewing system used in the camera. In general, this system does not deviate from one of the following systems: 1- Viewfinder system: Two lenses are used in this system, one for film and the other for the eye. There is a major defect in this system that is summarized by the existence of a small difference sometimes between what the eye sees through its lens and what the film sees through its lens, due to the difference

The location of the two lenses.

1- In the viewfinder system, a beam is directed from the subject to the eye, and another to the lens, and from there to the film slide.

2- The Twin-lens reflex system. Two lenses are also used in this system, one to direct light to a film slide and the other to display the image on a glass display screen. In this case, the eye sees a slightly larger image through the monitor screen. However, the previous problem still exists, which is summarized by the inaccuracy of the displayed image when the subject to be photographed is close to the camera. As the viewing lens is separated from the film lens. A new problem arises in this viewing system, which is seen by the eye on the glass screen turned right to left. In other words, what the eye sees to the right of the display screen is actually to your left, and vice versa. Although the picture is

2- In the double reflex lens system, a beam is directed to the vision lens, then it is reflected by the mirror towards the display screen, and another beam is directed through the exposure lens to the film slide.
This viewing system is widely popular due to the clarity of the images it displays and the clarity of the captured, as it is intended for cameras with a 120 mm film structure. picture

3 - The Single Lens Reflex System This system is based on the use of a special mirror or prism to direct part of the same image that the film sees to the eye so that it can see it through the viewfinder window. The right and left remain the same here, and the eye sees the same as what the film sees without any difference. For this reason, many photography enthusiasts consider this viewing system ideal, and it remains more expensive than the previous two systems.

- In the single lens reflex system, part of the ray seen by the film is directed to the eye by means of a mirror and a pentagonal prism.