11. MOUNTING PICTURES

Mounting, as differentiated from matting, means the adhering of a picture to a backing. It is extensively used whenever the operation will not destroy any of the intrinsic value of the pic­ture. For example, all prints which have a plate mark showing or those which are hand-printed such as wood-cuts or engravings would lose in value if they were mounted. However, water-colors or sketches and paintings on paper as well as drawings can be mounted and will be the better for it because they will not buckle after framing. If an artist is framing his own pictures, he can use his discretion whether or not a picture should be mounted. If the framing is being done for another person, however, it is advisable to obtain permission before proceeding and particularly if the picture is a valuable original.Mounting is also used for reproductions of all kinds, maps and pictures on perishable paper which are to be preserved. A spe­cial board with a very smooth surface is manufactured for mounting, but any good cardboard, beaver board or pressed wood can be used.

Photographs and some other pictures are usually mounted on board before framing rather than with window mats. The mounting board forms the mat or background. Special care must be used in this case so that none of the adhesive is squeezed from under the picture on to the mat. In addition, the picture must be placed in the exact position on the mounting board. To eliminate the latter problem, mount the picture on a considerably larger board and trim it down later.As a matter of fact, it is better to mount all pictures on boards larger than the finished size, even those to be matted.

Oil paintings on canvas may sometimes need mounting on a piece of fresh canvas and then re-stretching. If the canvas is fragile, but the layer of paint is in good condition, this is an admirable way to preserve it from damage. Dents or tears in canvases are automatically removed in this way.

There are many adhesives (also called "moun-tants") and many ways of mounting. All of them are more or less satisfactory, but it is wise to select that method which gives the least warping when dry. Whatever method is employed for mounting, extreme care should always be used to avoid getting any of the adhesive on the face of the picture. Warping is caused by the gradual shrinking while drying of the paper or fabric which has been moistened. The more the moisture content is reduced while mounting, the less warping will be encountered. Adhesives

The familiar rubber cement, as is well known, will adhere paper to board smoothly and with a minimum of effort. However, because of its tendency to dry out in a relatively short time, it will lose its holding power. It may also discolor the picture mounted with it through chemical action. Its use must be completely avoided except for the temporary mounting of charts and pictures of no real value.

Good quality library paste will be found useful for certain types of mounting work, especially small pic­tures. It must be spread very smoothly and the work must be put under sufficient pressure until dry.

Mounting which appears to give the smoothest adherence is called wet mounting. Different adhesives can be used for this method, but the principle is that the picture to be mounted is dampened enough to lose its stiffness and its tendency to curl. It will stretch in size when wet, but while drying under pressure it will shrink and all air bubbles, wrinkles, etc., are re­moved. Wet-mounting usually requires the use of a process called counter-mounting, that is, the adhering of a sheet of paper to the back of the board before it is put under pressure or otherwise dried. The paper used for counter-mounting, drying at the same time as the picture, tends to neutralize the pull or warping of the board. The mounting of large reproductions is usually accomplished by this method. Warping can be reduced to a minimum, but never completely elim­inated by counter-mounting.

Another method of mounting, used chiefly for photographs, is called dry-mounting. It involves the use of a very thin sheet of dry mounting tissue placed between the picture and the board. Heat is then applied and the picture is permanently mounted.

The newest, and what appears to be the best method of mounting large pictures (paper) on board employs a synthetic latex compound. A coat of the compound is given the mounting support, the picture is carefully laid upon it and then rolled down from the center outward to press out all air bubbles. After pressure of medium weight for an hour or so, the mounting is finished. Warping is very slight and the mounted work does not acquire that "stiff as a board" quality but retains a certain flexibility. This factor helps greatly in reducing the frame-twisting tendency —which wet mounting has.

Mounting canvases which have been removed from their stretchers requires a rather different tech­nique. Before coating the back of the canvas with hot glue or synthetic resin glue, it is first roughened with sandpaper. It is then laid carefully on a piece of fresh, unsized linen which has been ironed smooth. The canvas is adhered by rolling and is placed under heavy, even pressure long enough to insure thorough drying. Tears or holes should be covered with waxed paper to prevent the pressing boards from sticking if any glue is forced through.

Valuable pictures and those on thin paper should only be mounted on illustration board or other white stock of high quality. Impurities in cheap pulp board may strike out through and discolor the mounted work. All mounting board should be smooth and com­paratively free from  imperfections. Pictures to be framed under glass need not be mounted on very heavy board, since the pressure of the backing board in the frame will hold them flat against the glass. Those to be framed without glass require heavy board or what is referred to as 2- or 3-ply mounting board. Pressed wood, beaver board and other process boards can be used to good purpose, particularly for extra large pictures.

The use of wheat or wall-paper paste for mounting has largely been superseded by newer adhesives on the market. Wheat paste is economical, easy to mix and use but it has the bad fault of attracting attack by mold or vermin.

If mounting is to be a regular part of one's framing work, certain basic equipment is needed. The most important item is a heavy hand roller such as those used for rolling down linoleum. It can be either of the single or double roller type, the latter perhaps being a bit easier to handle and giving greater pressure while rolling.

A table high and large enough to lay out the mounting board and the picture to be mounted at the same time is also necessary. It should have a smooth clean surface. To prevent the adhesive being accidentally spilled on the surface, cover the table with paper while mounting.

Push-pins will be very useful to have on hand for mounting. They are to be used for pinning down the picture so that it will remain flat while moistening or applying adhesive.

A press or an area large enough to lay the mounted work down evenly should be available. Extra boards or sheets of plywood should always be at hand to place over the work before weights are added.

Brushes and suitable receptacles for glues, etc., are all that remain to be added to the equipment.

Note: Before putting any mounted picture under pressure, make absolutely sure that the surface of the picture is free from adhesive. Wipe up excess paste around the edges also.

Rubber Cement Method

Lay the picture to be mounted on the mounting board and mark its outline. Next, place the picture face down on newspaper and using a stiff brush, coat its back evenly with the cement. Brush the area marked on the mounting board evenly. Allow both surfaces to dry completely and holding the picture by the corners, allow it to drop on the board. Press down with the roller and remove any excess cement by rub­bing with the fingers until it is loosened. Library Paste Method

Mark the position roughly on the mounting board and lay the picture face down on newspaper. Place push-pins in each corner and give the back of the pic­ture a smooth coat of paste. Lifting it by the corners, carefully place it on the mounting board immediately. Cover with clean paper and roll down, then lift the covering paper off, wipe up excess paste with a damp cloth and place under medium pressure until dry. Wheat or WaJl-Paper Paste Method

First prepare a thin solution of ordinary wall-paper, paste or use a mixture of casein paste according to the directions on the container.

Mark the position of the picture on the mounting board and lay the picture face down, securing the cor­ners with push-pins to prevent curling. With a very wet cloth or sponge moisten the back of the picture until it is limp and lies quite flat.

Using a wide bristle brush, spread a smooth, thin coat of paste on the board and also the back of the picture. Make sure there are no bristles from the brush, lumps of paste or other foreign matter on either pasted surface because they will show as bumps very distinctly after the work has dried.

Remove the pins, and lifting the paper carefully by two corners, lead it into place starting with the free end. Before rolling it down make sure that it is in position and reasonably smooth. Then, working from the center toward each edge, roll it down firmly, wip­ing up excess paste squeezed out by the roller. Do not be alarmed if bubbles persist or if it does not appear to stick properly in places. They will disappear as the picture shrinks while drying.

Turn the picture face down on a clean surface and cut a piece of wrapping or backing paper larger than the board. Brush a generous coat of paste on the mounting board covering it completely and then wet the paper thoroughly with a cloth or sponge. It is not necessary to apply paste to the paper. Lay it down on the board, and lifting one end, smooth it from the center outwards as before. Use a large, clean cloth or a regular, wide wall-paper hanger's brush. Do not attempt to smooth too large a surface at once and try to make it as even as possible. Turn the picture over again and trim off the excess counter-mounting paper with a razor blade.

Place the mounted work under heavy pressure, using either a press or several sheets of cardboard and heavy weights. It should not be removed until about 24 hours later.

The great drawback to this method is the amount of time consumed in counter-mounting and drying. It is partially offset, however, by the excellent work turned out. All wrinkles and buckles are erased while drying and it is practically foolproof because it dries so slowly the picture can be shifted or moved while mounting if necessary. Dry-Mounting Method

Mounting with dry-mounting tissue gives superb results. It is quick, clean and foolproof but unfor­tunately requires a large press with thermostatically controlled heat to make the tissue adhere properly. Because of the necessity of a press (which are only made in limited sizes), it is impractical for the framer to attempt using it. An occasional small picture or photograph may be mounted by this method using an electric iron, but considerable experimentation is necessary to discover the correct temperature. Too much heat will melt the tissue and too little will keep it from sticking. Caution must also be taken not to damage delicate colors with the heat. Unless a press can be purchased and much mounting of photographs is done, it had better be avoided altogether. Synthetic Latex

Compound Method

Mounting with these compounds is actually mount­ing with rubber cement, but with this difference: the mounting is done while the latex is in a fluid state and contact with air causes it to change chemically and practically weld the picture to the board. After this change takes place, no ordinary solvent of any kind including lacquer thinner will affect it. Once mounted, the picture can never be removed. While the compound is in its milky-white state it can be diluted with water.

Mark the position of the picture on the board and brush an even coat of the adhesive on, keeping the strokes straight across the board first one way and then crossing them. Work rather quickly with plenty of latex because the board may absorb some.

As soon as the board has been covered satisfactorily, lay the picture down carefully and lightly. Do not attempt to shift it once it has touched the adhesive nor try to smooth it down by hand. Starting at the center, roll it down firmly toward each edge. Then roll the entire picture, first in one direction and then across, using heavy pressure. Avoid getting any of the adhesive on the roller or the face of the picture.

Place the picture under medium pressure for an hour or so and the mounting is then complete.

If any bubbles occur which seem impossible to re­move with the roller, place the picture under heavy pressure for two hours or more. Wrinkles where the picture may have been kinked or folded can be re­moved while mounting by placing a piece of clean paper over them and rubbing or "ironing" them down with a bone paper folder, a very smooth knife handle or similar implement.

A word of caution: Do not attempt to mount thin papers with this method.

The brush should be washed out immediately with soap and warm water or it can never be used again. Mounting Canvases

Remove the canvas from its stretcher carefully and place it face down on a clean surface, smoothing out the edges which have been bent. Secure the corners with push-pins and roughen the back slightly with No. ½sandpaper.

Stretch a piece of pure, unsized linen (which should be larger all around than the canvas to be mounted) on another smooth surface, using push­pins around the edges.

Moisten the back of the canvas with a damp cloth and coat it with thin, hot glue. Lift immediately and lay it down carefully on the linen. Place a sheet of clean paper over the face of the canvas and roll it down from the center outwards using heavy pressure.

Lay waxed paper on several sheets of cardboard if you are not using a press and place the mounted can­vas back down. Now place more waxed paper on the face of the picture, add more cardboard, and then weights. It will be dry enough for re-stretching in four to six hours. Finishing Mounted Pictures

Sprayed lacquer is of course the most efficient and desirable method to use for coating mounted work, but because spraying equipment is not usually owned by the average home craftsman, it will not be con­sidered in this section.

Brushing lacquer is very difficult to handle and should be avoided completely. Its quick drying prop­erties make a smooth finish virtually impossible except for very small pictures.

Occasionally, mounted pictures such as good-sized photographic enlargements, reproductions of original works, maps and so forth, are framed without glass. It is therefore necessary to protect them from soiling by giving them a coat of varnish and/or wax.

In place of lacquer, mastic picture varnish will be found most suitable. Because of the varying rates of absorption of printed and painted surfaces, it is advisible to size the surface to be finished with a glue size. LePage's glue, diluted with water to a very thin, watery consistency will serve well.

Always use a good varnish brush and flow the size or varnish on in order to reduce brush marks to a minimum. Sizing and varnishing should only be done in a dust-free room of even and not too low tempera­ture.

Photographs need not be varnished but can be pro­tected by waxing with paste wax and then polishing.

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