Intensification 
Tue Mercury INTENSIFIER.—This is probably the most 
generally used of all intensifiers. The silver image is treated 
with mercuric chloride or bromide until bleached, then 
washed, and blackened by various reagents. The mercuric 
halide solution is sensitive to light and should be kept in the 
dark. It is extremely poisonous when taken internally, but 
the absorption by the skin, even in the case of cuts and abra- 
sions, is practically harmless. Make up the following mer- 
cury solution: 
Mercuric chloride 20 g 154 gr. 
Salt 20 g 154 er. 
or Ammonium chloride 20 g 154 er. 
or Hydrochloric acid 3 ccm 23 min. 
or Potassium bromide 20 g 154 er. 
Water 1000 ccm 16 oz. 
The purpose of these additions is to increase the solubility 
of the mercury salt, and the bromide gives greater increase 
of density than the others. The plate to be intensified should 
be perfectly free from hypo, and if dry, soaked in water for 
10 minutes, and then immersed in the mercury solution until 
the image seen from the back is white; on no account should 
the action be stopped before this point is reached. It should 
then be well washed in water acidulated with hydrochloric 
acid, 1: 300; about 5 minutes soaking in six successive baths 
may be used; then, after washing in running water for 10 
minutes, it may be blackened. The acid bath removes the 
mercury salt, which is tenaciously held by the gelatine, and 
might otherwise give rise to stains. This acid treatment may 
be avoided by the use of the following bleach: 
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