I

As a precaution against a disaster first copy the old print in the same size. Soak the faded photograph for several hours in clean water and, after separating print from mount, immerse the former in nitric acid, highly dilute (1 per cent), for a few minutes. Then the print is kept in a mercury intensifier (mercuric chloride, 0.5 ounce; common salt, 0.5 ounce; hot water, 16 ounces, used cold), until bleached as much as possible. After half an hour's rinsing, a very weak ammonia solution will restore the photograph, with increased vigor, the upper tones being much improved, though the shadows will show some tendency to clog. The net result will be a decided improvement in appearance; but, at this stage, any similarly restored photographs should be recopied if their importance warrants it, as mercury intensifier results are not permanent. It may be suggested that merely rephotographing and printing in platinotype will probably answer.

II

Carefully remove the picture from its mount, and put it in a solution of the following composition:

By weight Hydrochloric acid. ... 2 parts

Sodium chloride..... 8 parts

Potassium bichromate 8 parts Distilled water.......250 parts

The fluid bleaches the picture, but photographs that have been toned with gold do not quite vanish. Rinse with plenty of water, and develop again with very dilute alkaline developer.