The chemicals used are such that, unless employed by experienced hands, they may cause irreparable damage. Practically all good print shops can arrange to have this work done satisfactorily. No print, regardless of condition, should ever be discarded without first consulting a reputable print expert about its value and the possibilities of restoration.
A print with an evenly mellowed surface, even though much duller than it was originally, is in collectible condition. Any attempts to brighten its colors would be useless and would add nothing to its value. Valuable prints are fastened to cardboard by using hinges, similar to those used in mounting stamps. On large folios, three or four hinges are necessary on the small ones, two or preferably three. These hinges can be made of any kind of gummed cloth tape, but it is better to use a glue that will not stick too tight and tear the print if they need to be removed. One inch or more wide for small folios, and two or more inches wide for large folios are the best sizes for the hinges. The outside ones should be flush with the edges of the print. This prevents torn corners. Hinges are, of course, fastened to the back of prints,
The cardboard on which the print is mounted is two inches or more larger in each dimension than the print itself. It is a good idea also to cover the print with a piece of transparent paper similar to cellophane. This paper is glued to the cardboard all around its edges and allows the print to be seen and handled without danger of injury, and keeps out dust and air.
There are some print cabinets that have drop fronts and the prints are filed in upright position. For prints kept in such a cabinet, the method of mounting just outlined is almost mandatory. Desirable cabinets can sometimes be acquired at auction sales of store fixtures. I have even seen some made of old pine feed boxes. These, when cleaned and finished, fitted very well with other antique furnishings. Old spool boxes, such as were used in country stores, are suited to small folio prints.
Surface dust and grime can be removed from prints quite easily by anyone. It is accomplished by going over the print with what is known as a "kneaded" eraser. The strokes should be light, and care should be exercised so that none of the descriptive lettering or coloring is removed. I have heard of such practices as covering a print with cornstarch and putting it in strong sunlight, but the eraser method is conceded to be the best and safest way to clean off surface grime. A very dirty margin can be whitened by rubbing lightly with powdered pumice, but this should never be done to any part except the blank margins.
Aside from these suggestions, there is little that the collector can do to correct damages that have occurred through the years. However, there is much that can be done to prevent further deterioration. Stains and foxing, if not too pronounced, can sometimes be removed or rendered less prominent by careful use of a bleaching compound. Such "washing" should be done very cautiously, for it can damage colors and even rot the paper. Ordinary laundry solutions such as javel water or clorox will do this cleaning, but they should be well diluted, and an inexperienced collector should not attempt such cleaning on a print of value. Have the work done by a professional who knows when to stop, rather than run the risk of ruining the print by overdoing the washing.
Slight tears on the margins of prints can be repaired by backing them with other paper. For this, it is best to use photographic mounting tissue and to cut the patches as small as possible. Do not use library paste, as it wrinkles the paper when it dries.
With a print on which the margins have been trimmed for framing or other reason, the only thing to do is to have it carefully matted by a good picture framer. If the margins have been only partially removed and the title is still attached, such damage is not too great, but is always to be regretted.
Prints that are to be hung on the wall require a different mounting than those kept in file cabinets. Most of the damages already mentioned are the result of improper framing, which allowed dust and air to reach the print. Valuable prints that are to be hung on the wall should be as nearly dust-proof and air-proof as possible. The best method is to make an airtight unit of glass, print and backboard.
A strong piece of cardboard, preferably not wood-pulp paper, is laid flat. On this is placed the print, then the mat, if one is to be used, and finally the glass. The edges are fastened together and sealed by using passe partout binding or similar tape. This complete unit is placed in the frame. Another backboard of cardboard is added, and then over this is placed the customary wood backing. The latter can be omitted if heavy enough cardboard is used for the second piece of backing. After the backboard is tacked in, a piece of strong manila paper is glued to the frame but not the backboard. About every five years the glued paper and tape should be examined to see if they need replacing. This method of framing gives almost perfect protection for any print.
Margins of prints should not be cut to fit a frame. Have the frame made the exact size of the print including the margins. The only time margins are trimmed is when they are badly dog-eared. Even then, it would be better to repair the margins by using transparent tape and filling in the holes with bits of old paper from a worthless print. It is the usual practice to have the width of the margin at sides and top the same. The bottom, which has the descriptive printing, is somewhat wider. This printing should not be covered by the frame or mat, if one is used.
The ideal way to keep unframed prints is in a cabinet with drawers large enough to allow any size of print to lie flat. For complete protection from air, dust and handling, these prints are mounted in hinged folders of heavy cardboard. Sometimes the tops of the folders are cut out like a mat to show the print. In other cases, the print is mounted on heavy cardboard and a piece of strong manila paper glued on to make a cover. Even the least valuable of prints should not be filed away without some sort of protection between each print, such as a sheet of tissue paper placed over the face of each one.
Prints should never be kept rolled. When one is acquired in this condition, the best way to take out the curl is to place it face down on a table, weight it with books, heavy boards or a slab of marble and leave it for several days. In doing this, work cautiously, since sometimes the paper is brittle and will crack if not handled gently.