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The Barnet Book of Photography A Collection of Practical Articles

When all is ready for exposure


[Illustration:

Fig. 2.]

Supposing that some arrangement of this sort is devised, we must unpack some bromide paper and put it in its box and then put a negative of "average" density in an ordinary printing frame. On the film side of the negative we must now place a sheet of bromide paper with its sensitive side in contact, replace the back of the frame and it is ready for exposure. Before exposing it, _make sure that both boxes are shut_ or their contents will be ruined the moment the white light is turned up.

Upon reference to the instructions that accompany each packet of bromide paper, you will observe a certain number of seconds' exposure is advised at a certain distance from the light; in the case of the Barnet extra rapid paper the time is given as about four seconds at a distance of eighteen inches.

When all is ready for exposure, place the printing frame upright opposite the lantern at the mark indicating eighteen inches (see fig. 2), note the time on the seconds hand of the clock and throw the lever over for white light for four seconds and then reverse it. Remove the paper and if many are likely to be required from that negative, it would be well to develop the first print in order to judge as to the accuracy of the exposure. If over or under-exposed, the time must be reduced or lengthened as required. When the best time and distance has been ascertained for a certain negative,

mark it with a narrow strip of paper bearing full particulars for future guidance, such as: "4 sec., 18 in., No. 5 Bray;" in this way absolute correctness of future exposures is assured. Of course, if gas is not obtainable, magnesium ribbon may be used instead. In this case the negative would be marked "1 inch (or more) ribbon, 3 ft. distant," as the case may be.

_Using Masks and Discs._--Prints are sometimes required with an oval (or square) centre and white margins: this is effected by interposing a black mask of the desired size and shape (obtainable from all dealers) between the negative and the sensitive paper. The black paper prevents the passage of light and leaves white margins to the print. If grey margins are required, a disc (to fit the mask) is attached to a sheet of glass the same size as the negative and arranged so that registration is easily effected; the print is first made with a mask and is then placed in contact with the disc and plain glass (the negative being removed from the frame), and again exposed for a second to the light. If a black border is required the exposure of the margin must be extended three or four seconds.

_Vignetting._--To vignette bromide prints, the printing frame must be covered with a piece of cardboard in which a small hole (about 1-1/2 inches by 1 inch for a cabinet head and bust) is pierced. The hole _must_ be covered with a sheet of white tissue paper which will diffuse the light and cause it to travel without harsh lines beneath the opening, and make the print with perfectly gradated edges. It is sometimes an advantage to move the negative while printing vignettes; but it is not absolutely essential if the hole in the cardboard is not too large and if the card is removed some little distance from the negative. If the card is too close to the negative, the gradation will be abrupt and the vignette will not look well.


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