TRICKS OF THE TRADE

Otago Daily Times, Issue 22964, 20 August 1936, Page 17

TRICKS OF THE TRADE

In giving you these hints I wish to make myself perfectly clear by saying I refer to photographs, engravings, etchings, and the like, but not to oil paintings (says an exchange). The latter is a job that really cannot be undertaken by the average housewife, who may do more harm than good A good oil painting needs the deft hand of the expert—and a real expert at that! Most other pictures are in a different category, and come within the scope of the average housewife to clean —and renovate. First of all, photographs. Before cleaning any photograph, first determine how it is finished. If it is finished with a collodion surface coating it can be wiped with a lag dipped in cold water. The marks will then disappear quickly. But if the picture be coated with gelatine, a very little pure alcohol should be used: that is. the face of the print should be gently rubbed with a soft cloth, lightly dampened with the spirit. To find out which of the two coatings has been used, the photograph should be lightly dampened at one corner. If it docs not feel sticky to the touch the surface has been coated with collodion. Some housewives clean engravings the wrong way and then wonder why the result is unsatisfactory.When I am cleaning an engraving, I fasten the picture on (o a strong, smooth piece of board, then cover it with a mixture of lemon juice and fine powdered salt. Next, I clean it quickly with a little boiling water, then dry in the air. Whatever you do. do not attempt the drying near a fire or in the sun. If you do it will result in the Dicture "yellowing." When an engraving is marked bv grease, a soaking in pure benzine will usually get it out. Any ordinary stain is removable by dipping the paper in a solution of freshly-prepared chloride of lime, after first soaking it in a weak acid solution. Mere dirt, such as smoke, may often be removed by soaking it in a soda solution. But this requires care, and the housewife will be well advised to resort to a light rubbing with breadcrumbs in order to remove the defectWhere a picture develops brown spots, commonly known in the trade as " fox" marks, the defect is mostly due to damp penetrating the back. Providing the mark is only slight it can usually be removed by touching the SDot with sDirit of wine, and when drv it should be touched again with a weak solution of oxalic acid. Spots on old engravings can also be removed, as a rule, bv applying a weak solution of ammonia.

Where a print is in such a condition that it reciuires washing, it is best to leave that to an exnert. who will then devise the best bath, and thus avoid damaging the picture. Manv a valuable picture has lost its lovely sky and bold outline simplv by being subjected to too much wet and drastic chemical dirt-removing agents. is an art. too. in drying a print after it has been immersed in such baths.

Tiie heat must be gradual—and uniform —otherwise you cause the paper to " cockle " and wrinkle, and entirely spoil the appearance of the picture. The only safe way is to dry it between two sheets of white blotting paper, and press with a warm iron. But hei-e, again, the heat of the iron must be such that it suits the print in each case, otherwise you obtain a yellowness and a gradual bleaching of the colour in the print as time goes on. Papers in pictures vary so widely, and so do the materials such as the inks and colours, that it is difficult to lay down a reliable formula for the housewife's guide. But if she is in doubt, she will find most art dealers ready to offer suggestions—even though they are not undertaking the job.