Visual tip-off

It is possible to use two coupled a photolamp, including them for the period of a spadework consistently, and at the moment of exhibiting - in parallel. At consecutive inclusion each lamp eats half pressure of a current and burns in half-heat, but is bright enough to make by the light of two lamps tip-off on sharpness and other operations. At such mode of burning of a photolamp serve as long, as well as usual. For switching of lamps from a consecutive food on parallel it is necessary to make the switch. For its manufacturing it is possible to use ready bipolar driven the switch applied in radio engineering. As cursors are connected by among themselves isolating crosspiece, short circuit possibility is excluded. At turn of the switch towards contacts of 1-2 lamps will be included consistently, and at turn to contacts 2-3 - in parallel. Experience with the switch has shown that service life of photolamps can be increased such way to 5-6 times in comparison with term of their service without the switch. Photolamps join in vertical position by a flask upwards or in horizontal position. Inclusion of lamps in inclined position by a flask from top to bottom reduces service life of lamps. At vertical burning кол downwards lamps very quickly fuse fight. Lamps should be applied only to that pressure for which they are intended. Tip-off on sharpness The good picture should be first of all sharp. Even the most insignificant not sharpness of the main object of shooting deprives a picture all which value. To correct such picture it is impossible. Especially the great value gets sharpness of the negatives intended for the subsequent increase. On the first way tip-off it is made by supervision over degree of sharpness of the image on matte glass of the chamber at moving of an objective or its forward lens. Accuracy tip-off in this case is defined only by visual acuity and quality of matte glass. The last should be rather small frosted (fine-grained). Coarse-grained matte glasses for this purpose are absolutely unsuitable. Accuracy degree tip-off raises at magnifier use. Quality visual tip-off that above, than is brighter the image on matte glass, therefore visual tip-off it is necessary to make at a full (maximum) aperture of a diaphragm.