اظهار الالواح الزجاجية او الافلام المسطحة .. كتاب التحميض والطبع والتكبير

Third: Showing the glass panels or flat films:

The single flat film or glass plate can be shown in the usual display basin by moving the basin from one side in a periodic motion up and down (as shown in Figure 1-18) or by holding it with a special clamp and moving it in the directions shown in ( Figure 18-b) If there are more than one films, then it may not be possible to avoid the films sticking to each other during the display process in the dark, especially if the basin is not wide enough and the amount of the solution shown is large, as the films may swim in the solution and accumulate on top of each other. Here we recommend one of the following methods:

1- Making handles of celluloid (Fig. 19) to hold the films or glass panels, thus making it easier to move them in the solution that appears in the dark without sticking to each other.
2- Using an appropriate display tank as in (Fig. 20, 21).

Show feature films by automatic means:

No practical difficulties arise when showing a sensitive glass plate or a flat or small roll film (whether its size is 6 x 9 cm or 35 millimeters as those used in conventional cameras), but some practical difficulties may arise when showing long films that Their length may sometimes reach 1,000 feet, for example, which calls for the use of large display machines known as Processing Machines run by electric motors. These machines consist of several large tanks that hold the different solutions needed for the processes of displaying, stopping, fixing and washing, and in them the film moves automatically between these tanks in a vertical movement from top to bottom and then up again, and so on, and the film runs on rollers with sizes that suit the film sizes (whether 35 mm or 16 ml or 8 ml, for example) so that each process takes place in a specific period of time that depends on the speed of the machine, the number of tanks, and the degree of chemical activity of the solutions used.

And there are modern machines money. Its design allows the films to flow in tanks filled with solutions. Rather, displaying and other operations are carried out by spraying the film with a quick successive spray of these solutions. The difference between the process of displaying when the film runs inside the solutions in the tank, and displaying by rapid successive spray, can be likened to the difference between the process of bathing in the bathtub and showering under the mist of the shower. And the same is the case if the display was done by spraying, then every drop of the solution spray plays its role in showing the latent image, and this is a guarantee that the apparent solution will be at its maximum activity on a continuous basis, as it is always renewed and not exhausted.
There is another way to display medium-length wrapped films (such as 16 mm amateur film flags or films known as microfilm), in which the film is wrapped around a rotary drum (Fig. The drum is run for a specific period of time until it is shown, and then the drum is moved to other basins for washing and then fixing...etc. It is obvious that all these operations were done in a laboratory that is lit only by the safe light that is suitable for the type of film.

There is another method of display, known as Viscous development, and it is used to show feature films, and sometimes to display the optical sound track on the film. According to this method, the thickness of the display solution is increased with special materials that may be gelatin or Carboxy-methyl cellulose. The film is run in a special displaying machine where it passes through rubber cylinders to remove any excess traces of the sticky displaying solution.