CLEANING OIL PAINTINGS

Dominion, Volume 22, Issue 94, 15 January 1929, Page 15

CLEANING OIL PAINTINGS

There are several ways of cleaning oil paintings, and a method that would successfully clean one painting would totally ruin another which has been finished with a different kind of varnish, an English authority observes. As it is very difficult to tell what kind of varnish has been used, it is necessary to experiment on a small, unimportant corner of the picture. Hard mastic varnish can often be removed with the tips of the fingers, or a bottle cork, rubbing the varnish to a powder. For the removel of copal varnish, a mixture of spirits of wine and oil of turpentine will be required. This should be poured on a clean, soft rag, and rubbed gently over a small part of the picture. As soon as the varnish has dissolved, it should be immediately wiped away with a clean rag. If this fails to remove the dirt, use soda,' potash, or carbonate of ammonia, washing off frequently with clean water. For soft varnishes, spirits of wine of 56 strength should be used, diluted with a sixth part of rectified spirits of turps. Rub about two or three square inches of the picture until clean, then immediately rub over with rectified spirits of turps only, which will harden the colours, and prevent them coming off. When the whole picture has been cleaned, wipe over with turps, let this evaporate, and revarnish. Watch the rubber for the slightest appearance of colour, and immediately apply the turps. Use plenty of clean rubbers. Unvarnished pictures are cleaned with a damp washleather, and poivdered pumice or -whitening. To clean a picture, coated with size, isinglass, or albumen, use clean water, warmed if necessary.

Some liquids destroy within a short time corks with which they are sealed. To make such corks resistable against chemical action, place them before using into a mixture, heated to 104 Fahrenheit, consisting of 2 parts vaseline and 7 parts paraflin. The further impregnating process is also recommended Keep the corks for 2 days in a 10 per cent, solution of gelatine at a temperature of 86 degrees F. The temperature must be kept at this point during the 2 days to prevent the gelatine from congealing. Remove the corks from the solution, let them cool for a whole day to thoroughly set the gelatine, then dip them into diluted potassiumbichromate. The chrome-gelatine thus chemically formed will become absolutely 7 indissolvable by the influence of light.