This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Another Method Of Blocking The Negative. By the following method not only is the negative blocked, but the blocking is also vignetted. First take a piece of printing-out paper the size of the negative and make a proof print from it. Next, take a piece of opaque paper the same size as the proof, place them together, and with a pair of shears, cut along the sky line of the proof, through the proof and the opaque paper at the same time. It is not necessary that you follow exactly every tree or piece of shrubbery, but if buildings are in the view follow the lines closely. For distant objects there is no need to be so particular. Save both masks. The sky portion of the proof you fasten to the negative with paper stickers attached to the edge of the print and negative. This mask will absolutely protect the sky from printing.
1158. In order to avoid a sharp line take the opaque paper mask, paste it to a card a trifle larger than the mask, with the cut-out edges overhanging the edge of the card. Place this card on the outside of the printing frame, overlapping the inner mask about one-quarter inch; then place the sensitized paper on the negative and print in the usual way, printing until the foreground is fully printed. The mask on the outside of the negative will have the effect of breaking the line of the inner mask, thus giving a slight vignette to the inner mask, preventing a sharp line. After the foreground is printed, place the print in the printing frame containing the cloud negative, fastening the proof of the foreground mask over the negative. On the outside of the frame attach the opaque mask, arranged in a similar manner to the first vignette, and again place the negative out to print. The outside vignette will again assist in overcoming the sharp line which would be visible if the cutout mask were used alone.
Blocking With Gamboge. Where printing is done on printing-out paper, with the image visible when printed, the use of gamboge for blocking out the image on the print for second printing may be employed.
1160. While gamboge can be applied to landscape work, it is more useful for portraiture, especially for reproductions in which it is desired to copy a picture, cutting out the old background and printing in one more suitable. This is done by double printing, though instead of using a paper mask for the first printing, an opaque or water color mask is employed directly upon the negative. The same opaque used for blocking out vignettes, formula for which has been previously given, is suitable for this purpose. For the second printing apply the opaque to the print. The best opaque for this purpose, however, is gamboge, as it will not stain the print as other opaques may.
1161. If you were to make an outdoor portrait with a brick wall for a background and it was desired to do away with the brick wall, it would simply be necessary to paint a line carefully around the figure, using opaque for the purpose. After this line has been drawn the color may be applied quickly to the remainder of the background. If the negative is large the greater part of the ground may be covered with opaque paper instead of paint. The paper mask can be pasted to the edges of the glass side of the negative, while the finer details of the outline are painted on the film side. After the figure is blocked out place the negative on the sheet of printing paper and print to the desired depth. Then remove from the frame and with a thick solution of gamboge, proceed and paint over the surface of the print, covering only the figure or the printed portions. Exercise care that you do not work too closely to the edge, because to overlap would leave a line. Better not block far enough than too far, as if not blocked enough, those portions unblocked would only print darker, and, as usually a dark background negative is used for second printing, the margin will show but little. However, if you block over the outline a white line is left, which will have to be spotted out in the finished print.
1162. After the gamboge becomes dry, which will require but a few moments, place the print upon some selected landscape negative suitable to the picture, and print the background to the same depth you have printed the figure. The gamboge, if properly applied, will prevent the figure from printing, and when both portions are printed to exactly the same depth they should show no trace of the double printing. When the printing is completed, the coloring matter used to protect the figure is washed off, and you will then have a print of the portrait, to which has been added a suitable background. Washing, toning and subsequent operations are then carried on in the usual way.
1163. Should there be slight flaws or imperfections in the outlining of either the print or the negative, with a little touching out on the finished print, with spotting color, they can be removed.
1164. In selecting a background for figures be careful that the lighting of the combined negatives is from the same direction. For example, if the portrait was lighted from the right and the background surrounding it showed light coming from the left, a false result would be produced.