This section is from the book "Modern Photography In Theory And Practice", by By Henry G. Abbott. Also available from Amazon: Modern photography in theory and practice: A hand book for the amateur.
The last process, that of trimming and mounting the print, is a simple one and yet how often do we see an otherwise beautiful photograph handicapped by poor trimming and an unappropriate mount. One of the first considerations is that the print be trimmed perfectly square. This we cannot expect to do by means of a pair of shears, using the eye only as a guide. The Perfection Trimming Board, shown in Fig. 55, is an effective method of securing square prints. It consists of a solid wooden tablet with raised edges, containing a card on which are printed diagrams of all the different sizes in general use, from 1 3/4 x 3 1/2 to 8 x 10. This diagram is covered with a stationary thick glass on which a movable glass pattern is placed. The print to be trimmed is laid in place under the glass pattern, which is held firmly against the raised edge of the board, to prevent its slipping and with a sharp knife two of the sides are trimmed. The print is then reversed and the other two sides are cut. There are also many excellent trimmers on the market in the form of bench shears and rotary cutters.
If the amateur has a large number of prints to mount, or should he be so located that he cannot reach a photo supply house readily, it may pay him to make his own mounting paste but as a rule it can be purchased so cheaply in tubes and jars and is so convenient that it will only be in emergency cases that he will want to make it. A good, all-round mounting paste can be made by boiling starch to a very thick paste and then straining it by forcing it through a fine cambric bag. The paste should be so heavy that it will not go through the cambric unless the bag is twisted, thereby forcing it. A little ground alum, dissolved in hot water and mixed with the paste, will prevent it from turning sour. The prints should be laid one on top of the other, face down, on the pasting board and the paste applied by means of a broad, flat brush. It is a mistake to use a small brush, for the print is dry on one end before the other is fairly pasted.
As to the style and color of the mounting cards, taste alone must dictate, as there are so many colors and finishes on the market and as the subjects of prints differ so materially, no hard and fast rules can be applied but by all means select mounts which have a liberal margin, for nothing looks so mean as a good sized print on a card with a skimpy margin. Our preference is for dark rather than for light mounts and for plain rather than glossy finish on the cardboard. You can make mounts which are highly artistic and different from those usually found on the market. Take a piece of Whatman's, or any other rough drawing paper, a little larger than the mount you require. Cut a piece of zinc, say a half inch larger than your usual prints, or about the size of the dry plate you are using. This zinc you can leave with a plain square corner, or you can round off the corners, as fancy dictates. Place the drawing paper on a smooth piece of board, put the zinc sheet in the center of it and apply pressure, either by putting it in a copying press, or placing a board and heavy weights on the zinc. If sufficient pressure has been applied, the result will be a smooth center in which to mount the print, with a rough border all around it. The smooth sunk surface should be at least a quarter of an inch larger all around than the print. Should you want a mount heavier than the drawing paper alone will give you, then you can paste the drawing paper upon a piece of pulp board but in this event the zinc should not be applied until after the paper is pasted in position.
There are a number of rough papers on the market in white and various tints, which are used as covers for pamphlets and any of them, when backed by a piece of straw board or pulp board and a sunk panel made in them, will make very artistic mounts. Even the common straw paper, such as used by grocers and butchers for tying up packages, if properly treated, makes a very artistic mount by backing it with board, pressing a shape into it and drawing a simple line around the shape with India ink and a ruling pen.
Don't be afraid to sacrifice a half or even two-thirds of a print in order to secure that which is of interest and the least that you show of the uninteresting the more you accentuate that which is picturesque or artistic. It would be far better to cut down a print to 4 x 4 and thus have an interesting one, than to have the same occupy the center of a 5 x 7 print and the balance of the picture consist of uninteresting foreground of grass and the sides of a like character. Do not cut and slash your print recklessly, otherwise you may cut it down too much. Go at it systematically. Take four pieces of colored cardboard or paper and lay them over your print so as to form a frame, cutting out that which you think of least interest. Now, by drawing in and extending out the four limbs of the frame, you can judge very accurately how your print will look when cut to a certain size.
When your prints are mounted, if a glace finish is desired, they should he passed through a burnisher. The burnishing roller should be kept bright and clean and should never be used cold. The prints should be burnished within a few hours after they are mounted, or while they are still slightly damp. The prints should be lightly rubbed over with a piece of flannel and white castile soap. A very small quantity of soap is all that is required, otherwise you will gum up the burnisher. Should you desire a glace finish and you cannot afford the luxury of a burnisher, you can secure it in the following manner. When your prints are all thoroughly washed, lay them out on blotting paper sheets, face up, to dry. When they are thoroughly dry dip the face of the print again in cold water and place them, face down, on a sheet of plate glass or a ferrotype plate and press them into close contact with the face of the plate by passing a squegee roller over the back of the print. An ordinary ferrotype plate will take eight 4 x 5 prints. When you have them all squegeed down, take up the surplus moisture from the backs with a sheet of blotting paper and stand the plate on edge until the prints are thoroughly dry. With most papers, the prints will have a tendency to stick to the plate and to obviate this, the ferrotype plate should first be treated by rubbing it with a piece of flannel and paraffine solution. This solution can be purchased from your dealer, or it can be made by dissolving paraffine in benzine. The paraffine should be shredded and placed in a bottle and the benzine added to it. Shake thoroughly, cork the bottle well and place it in a warm place and the paraffine will gradually be dissolved. The ferrotype plate should be rubbed with this solution before each new batch of prints is applied. A very slight film is all that is required on the plate. If your printing paper is heavy you can mount your prints without affecting this finish in the slightest, providing you are not too lavish with your mounting paste. If, however, your printing paper is thin you will have to proceed differently After you have squegeed the prints down upon the plate, paste the backs of them and squegee a piece of thin paper to the back and allow all to dry. This extra piece of paper will prevent the paste striking through the print and destroying the finish. Do not force the drying of prints which are squegeed to a ferrotype plate by placing them on the stove, or you will melt the gelatine on the face and make the print stick harder than ever. The surface of these prints sometimes has a higher finish than can be secured by means of the burnisher.
On page 58 we mentioned the scrap book and this, by the way, is a very important thing and no dark-room should be considered complete without one. In this book should be preserved the printed directions which accompany the various makes of plates, developers, papers, etc. and in it you can preserve clippings from trade papers, etc. The book should have an index and should be paged, so that when you want a certain receipt or formula, or are at a loss how to proceed, you can consult the index and find the formula or directions instantly. If you take one or more photographic journals and have a number of annuals and books on photography, you can put in a rainy Saturday afternoon to good advantage by preparing an alphabetical index which will show you at a glance just where you can find an article on a given subject, or any particular directions or formula. Index your periodicals by volume and number, or by year and number, also giving the page and it will save you a world of time and trouble when you wish to read up on any particular subject.