We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
230 History of Three-Color Photography
The shreds should be collected on a sheet of well-washed linen, an old handkerchief is excellent, and some distilled water poured over them about five times, when they will be washed enough. The ends of the cloth should then be gathered together and twisted round and round so as to squeeze out as much water as possible. The emulsion shreds should then be added to about 400 ccs. of alcohol, or this quantity may be poured gradually over the shreds in a funnel, while still in the cloth, the shreds being well stirred to bring them as much as possible into contact with the alcohol; the idea being to free them from as much water as possible. This alcohol may be used two or three times, and finally as much as possible pressed out. The damp emulsion should be collected, placed in a flask and 250 ccs. absolute alcohol added, then well shaken for 5 minutes and allowed to stand for 24 hours. After that time 150 ccs. of the liquid should be run off, 150 ccs. of absolute alcohol added, in which 0.5 g. of narcotin has been dissolved, then 250 ccs. ether added, and the mixture allowed to stand 3 days with occasional shaking. The emulsion should be filtered through a pad of absorbent cotton, that has been well wetted with absolute alcohol. It is necessary to use a filter pump for this, otherwise the filtration is too slow and the loss of solvents considerable. Finally should be added 500 ccs. alcohol-ether, and the emulsion is ready for use.
Chloro-Bromide Emulsion. — Prepare 700 ccs. of plain collodion, as advised above, and add the following :
Silver nitrate 50 g.
Ammonia 50 ccs.
Shake well till a perfectly clear solution is obtained, then add :
Alcohol, 95 per cent 100 ccs.
If any silver crystallizes out, add a few drops of water. To this must be added the chloro-bromide solution, as follows :
Ammonium bromide 27 g.
Distilled water 40 ccs.
Heat gently till dissolved and add :
Alcohol 100 ccs.
Then add :
Lithium chloride, 10 per cent sol 15 ccs.
This chloride solution is made by dissolving 10 g. lithium chloride in 10 ccs. distilled water and adding 90 ccs. alcohol. The chloro-bromide solution should be gently warmed before adding to the collodion, and the addition should be made in small lots with constant agitation. Allow the emulsion to stand from 2 to 4 hours, and place a drop or two on a sheet of glass and examine by transmitted light ; it should appear a fine orangered color. The emulsion is then precipitated and washed as described above for the bromide, and the shreds finally dissolved in :
Alcohol 350 ccs.
Ether 350 ccs.