A sky may be added to a transparency more simply, viz., by printing the cloud negative on a second plate, which afterwards takes the position and place of the usual cover The direction of the light in the cloud negative must be chosen with regard to the fact that the picture is reversed. This method allows an excessively dense sky to be corrected if neces sary, by reduction, and simplifies the register marking of the two pictures. A sky may also be transferred to a positive transparency with out any difficulty by the aid of a stripping posi tive paper.
519. General Hints. The glass of the frame or printer should be carefully cleaned on both sides, and the felt pads brushed before work is begun. The back of the negative should also be cleaned, if necessary.
Carefully place the negative correctly in the frame, with the gelatine side away from the glass support. Fix the mask, if any, in position. and then the sensitive paper or plate, the sensi tive side in contact with the negative, avoiding all contact of the fingers with the surface ; keep the whole in position by pressure with the hand while the first part of the hinged back is fixed in place.
To avoid errors in the number of prints to be made when using print-out papers, and if no counter is available, as many marks as there are prints required should be chalked on the frame and one rubbed out after each print is made. For prints on development papers it is
simpler to count out the required number of sheets of sensitive paper and place them in a separate box at the beginning.
In exceptional cases, where it is necessary to make a print from the reverse side of a film negative,' or even from a glass negative, parallel light or light from a point source at a great distance from the frame should only be used. If the printing is done in daylight, the frame should be placed at the bottom of a kind of long chim ney made of a wooden framework covered with cardboard or paper, blackened on the inside, or lined with black material, the whole being turned towards the sky. When printing by artificial light, the source of light should be as small as possible, and the frame placed as far from it as is convenient without prolonging the exposure excessively. If an enlarging or projection apparatus which is fitted with a condenser is available, an almost vatallel beam of light can be obtained by suitably adjusting the light-source. Printing can then be carried out nearer the lamp and with considerably shorter exposures.