الهالة الضوئية .. كتاب التصوير الضوئي

HALATION

If we follow the path of the light beam in the sensitive layer, we notice that Age through the sensitive layer first and spread to some extent in the gelatin, as we have already mentioned, and finally the beam reaches the support on which the sensitive layer is, whether it is of glass or celluloid, both of them have a shiny surface, so the rays reflect on them and then bounce back to the sensitive layer and affect another area adjacent to a point
​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​, and it becomes subject to reduction during the display process, even though it was not exposed to direct radiation. (fig. 74)

Finally, we find that the part on which the direct rays fell, which was supposed to be a single point of light, has become a light spot with a halo around it, and to prevent the occurrence of the optical state, the sensitive films and plates have been equipped with a colored layer whose function is to absorb the rays that reach the film support instead of reflecting it, and it is called Anti Halation Layer That is, the anti-halo nature. This layer is placed between the sensitive layer and the support. Or behind the pillar in some brands.
(Fig. 66) The light halo may be resisted by making the same colored support, as is the case in some 24×36 films. 3 mm. The anti-glare layer dissolves easily in the washing water, so it does not have any harmful effect on the images