Manual processing is done in a dark room with safelight illumination.Safelight refers to the light with a particular wavelight which does not affect the radiographic film.The illuminator is situated neat the site of handling the wet film.Exposure of film for longer than normal time in the safelighting conditions can adversely affect the image.Safelighting can be provided by red,brown or olive-green lighting.Safe illumination is usually provided by an ordinary bulb of not more than 25 watts with a coloured filter placed in front of the bulb to achieve the required hue.Safelighting can be direct or indirect.
In direct safelighting,the lamp has a circular filter 14 cm in diameter and fixed either to the ceiling or to the wall above the working bench.The safelight should be kept atleast 4 feet above the place where the film is handled.
In indirect safelighting the lighting is provided by a safelight which is directed towardsthe ceiling from where it is reflected back to the room.