نقل طبقة الجيلاتين الحساس من الدعامة .. كتاب التحميض والطبع والتكبير

Transfer of the sensitive gelatin layer from the support:

Some negative sensitive layers are prepared in a way that facilitates their removal from the original support and transferring them to another support (Transfer materials) if the matter calls for that. To achieve this purpose easily and proficiently, the following steps are followed in their preparation:

1- Increase the hardness of the sensitive layer.

2- A soft layer of non-sensitive gelatin should be placed between it and the abutment, facilitating its removal from above the abutment.

3- The upper surface of the sensitive layer shall be treated with an adhesive, so that it can be easily attached to the second support to which it is transferred.

Anti Halation Layer: Anti Halation Layer.
When a noon ray falls on the surface of the film, it suffers from a series of light reflections on the different shiny surfaces that make up the film (Fig. 6), and what is known as the light halo occurs in it (Fig. 7).

The optical halo can be overcome by preparing a radiation-absorbing layer known as the Anti Halo Layer, sometimes called the Anti Halation Layer, and it is placed in one of the following two places:
(A) Between the bottom of the sensitive layer and the top of the support (in place of the flat, land in Figure 6).
(B) behind the buttress. Behind the flat (M and: Figure 6).
The occurrence of the optical halo may be prevented by means of a colored support that absorbs the rays that reach it, as is the case in some 35 mm films. The anti-glare layer dissolves easily in the washing water prior to the start of image display operations, so it does not have any harmful effect on that.
Factors affecting the increase in corona damage:

The extent of damage to the image as a result of the occurrence of the optical corona depends on the following factors:

1- The thickness of the sensitive layer: the distance (B in Figure 6) decreases as the thickness of the sensitive gelatin layer decreases.

2- The thickness of the pillar: the distance (k) decreases whenever the thickness of this pillar decreases. The ratio between the thickness of the sensitive layer and the thickness of the support varies greatly, as it may not exceed the ratio of 1:10 in the thin films of the support, and it may increase to the ratio of 1:200 sometimes in some sensitive glass panels.

3- The amount of light carried by the incident ray:
It is evident that the different reflections increase with the increase in the amount of light. In addition to the light ray (and TCL) reflected from the point (F), other successive reflections occur such as (CT) then (MN)...etc as the amount of light increases.

How to identify a sensitive surface in complete darkness:

We noted above that the sensitive gelatinous layer is poured onto one surface of the film support. And there is no difficulty in knowing which surface the pen is. The sensitive surface if it is wrapped with roll film, the sensitive gelatinous surface is always the inner surface if the film is wrapped.

However, it seems difficult for the beginner to know (in complete darkness) which of the two sides of the sensitive glass plate or the flat film is covered with the sensitive layer, and this matter is of great importance both in the “chassis reconstruction” process (so that the sensitive surface is facing the lens). And not upside down) or in the process of showing. (So ​​that the sensitive surface is facing upwards, so that it does not scratch from the bottom of the basin).
The makers of the sensitive boards followed a certain fixed method in packing these boards, so every four boards were wrapped together in a black cover, so that the sensitive face of each two boards met together. They are separated by a separator made of cardboard placed on the sides to prevent friction between the two surfaces (Fig. 8). If we open the cover that includes the four sensitive panels, the arrangement of the sensitive surfaces is on
next face: It appears from the foregoing that it is necessary to maintain the arrangement of these sensitive panels in their rolls in the previous manner. After we withdraw from the roll what we need of the sensitive glass panels. If the photographer did something that violated this previous arrangement, then it is possible to identify the sensitive surface by bringing the tip of the sensitive plate close to the lower lip after wetting it with a toy, not a little bit with saliva. This phenomenon is not seen in the vitreous, whether it is covered with the anti-halation layer or not. Closer to the sensitive surface

As for flat films (Sheet Films, Cut Films, or Flat Films), work has been done in making them by perforating one of the corners of the film or placing a distinctive mark in computer systems, which is general, as small, regular cuts in one of the corners (Fig. 9) so that the sensitive surface is facing the photographer. When this cut was in the upper right corner of the film. Income in the world for rooms