| BY GEORGE L. RUFFIN GEORGE L. RUFFIN (1834-1885) the first Negro judge to be appointed in Massachusetts, graduated in Law from Harvard, 1869. He served in the legislature of Massachusetts two terms, and in the Boston Council two terms. ... Read more of Crispus Attucks at Martin Luther King.ca | InformationalPrivacy |
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| Home - Chromatography - Color Value - Aesthetics - Photography | |
Most Viewed- The Aniline Process- The Primuline Or Diazotype Process - The Cuprotype Burnett's Process - A Poitevin's Process 1870 - The Cyanofer Pellet's Process - The Cyanotype Or Blue Process - The Uranotype - Graphotypy - Dr Tl Phipson's Process 1861 - Choice Of Paper Sizing Least Viewed- Causes Of Failures- Preparation Of Red Yellow Or Blue Tissues - Tracing Process On Metal - X's Process 1865 Secrets Of The Uranotype - Houdoy's Process 1858 - Godefroy's Process 1858 - How To Make A Negative Drawing - Printing On Wood Canvas Opal And Transparencies - Guarbassi's Process 1867 - Cj Burnett's Process 1857 |
Guarbassi's Process 1867The paper is floated in the dark for four or five minutes on a saturated solution of bichromate of potash. When dry, it is printed a little longer than for silver prints and afterwards floated, face upwards, on a water bath until all the unaltered bichromate is dissolved. It is then immersed in the following solution, which improve by use and tones the pictures to a reddish color: Saturated solution 4 parts nitrate of mercury, as free from acid as possible Saturated solution 1 part bichromate of potash Distilled water 28 parts This solution should be prepared, filtered and allowed to stand for some time before use. The print is left in the bath until it has assumed an intense red color, the whites remaining perfectly pure. It is then washed and put in another bath to obtain a brownish tint. This bath is thus composed: Conc. aqueous ammonia 2 parts Distilled water 100 parts The print must be immersed at once, and when, in a short time, it has assumed the proper color, it should be washed immediately. The picture is toned in a very diluted solution of chloride of gold, 1:7,000, in which the color passes from a light brown to a deep black or a violet black tone, when it is washed in two changes of water. Next: A Poitevin's Process 1870 Previous: L Liesegang's Process 1865
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