This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Shadows Remaining Weak After Intensifying. If your negative is badly under-timed it is impossible to produce any detail in the shadows by intensification. The best way is to simply bleach the negative with mercury. Do not place in the clearing bath (sulphite of soda), but after staining all you can, wash thoroughly and set up to dry. The stain, if not cleared up, will slow the printing and give you all the detail it is possible to obtain from such a negative, and more solid prints will result.
Negative Intensifying In Streaks. If the plate is placed in the intensifying solution, and allowed to remain there without agitating, the intensification is apt to be streaky. Remedy: Always rock the tray both when intensifying and clearing.
Small Opaque Spots Irregular In Shape And Size. Opaque spots are generally caused by undissolved particles of bichloride of mercury coming in contact with the surface of the negative. Remedy: Always use the decanted clear solution.
Intensifier Will Not Work After Using A Few Times. If the intensifying solution refuses to work, it is because the mercury by constant use has become weak. Remedy: Strengthen by adding a trifle of fresh stock solution of bichloride of mercury, or if it still refuses to act, then the life of the mercury has become entirely exhausted, and you should make up a new bath.
Intensifying Solution Becomes Milky. This is caused by some of the sulphite clearing solution getting into the bichloride of mercury solution. Remedy: Discard this solution. Make up a new one, and be careful to never allow the sulphite solution to come in contact with the mercury. If you place your fingers in the clearing bath (sulphite of soda), wash them thoroughly before placing in the intensifying solution.
Appearance Of Old Negatives Which Have Not Been Properly Fixed And Washed. If the negative is very old, and it contains hypo, there will appear a vapor-like scum on the surface. It is then best to assume that it has not been properly fixed or washed, and if such a negative is to be strengthened, intensify with intensifying solution which contains hyposulphite of soda.
Removing Varnish. By carefully following the instructions given in the lesson, you should have no trouble in removing varnish. If the turpentine will not remove the varnish, try soaking the plate in alcohol. If when the plate has been soaked in wood alcohol, you find after rubbing with absorbent cotton that there still remains varnish, soak longer, use fresh alcohol, then wash for twenty minutes in running water, and you will find that all the varnish has been removed.
Bichloride of Mercury
... 30 grs.
. .. 30 grs.
... 6 ozs.
Add one ounce of the above solution to 4 ounces of water; in other words, enough water to cover the plate being intensified.
When thoroughly bleached in this solution the negative may be blackened in the usual way, by placing in the sodium sulphite bath, testing about 40 hydrometer test.
Monckhoven's Silver Intensifier.
Bromide of Potassium
Bichloride of Mercury
Cyanide of Potassium...........
..... 60 grs.
Nitrate of Silver
The silver and cyanide are dissolved in separate lots of water (3 ozs. of water for each), and the former added to the latter until a permanent precipitate is produced. The mixture is allowed to stand in the sun for 15 minutes, and after filtering forms Solution B.
Place the negative in Solution A until it becomes white; then rinse and transfer it to Solution B to blacken. If the intensification has been carried too far, it may be reduced by treatment with a weak solution of hyposulphite of soda.