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.
Three-Color Transparencies and Lantern Slides 445
Concentrated solutions flatten the pictures though they act quickly ; whilst very dilute solutions give more brilliant pictures though they take a long time. Weak borax solution may be used instead of ammonia to reduce the color.
Ducos du Hauron9 also recommended gelatino-bromide films for making the positives, using for his colors, for the blue :
Indigo carmin 60 g.
Water 1000 ccs.
For the red :
Nacarat red, anilin 30 g.
Water 1000 ccs.
For the yellow a saturated solution of picric acid.
R. Krayn10 in order to obtain extreme sharpness, made one of the constituent images on a stripping plate, and after completion of the dyeing, stripped the film and sandwiched it between the other two pictures, which were on glass plates. The stripping plate was obtained by fixing an ordinary silver emulsion stripping plate and dichromating. This plate with its image was cemented with gelatin in register with one of the other pictures and the two allowed to dry, though how this was to happen with glass on both sides is not quite clear. When dry the glass was stripped. A. and L. Lumiere11 used the following dyes for staining: For the red :
Erythrosin J, 3 per cent sol 25 ccs.
Water 1000 ccs.
For the blue :
Diamin blue pure FF, 3 per cent sol 417 ccs.
Glue solution, 15 per cent sol. to 1000 ccs.
For the yellow :
Chrysophenin G 4 g.
Alcohol 167 ccs.
Water to 1000 ccs.
Dissolve the yellow dye at 70° C. and add the alcohol.
E. Sanger-Shepherd12 described the method, which he had introduced commercially, in which celluloid, coated with gelatin containing silver bromide, was exposed through the back, after sensitizing with dichromate, and stained as usual. He suggested the use of a blue cyanotype-toned lantern slide for the blue impression, as this acted as a cover glass; the three films were cemented together with Canada balsam.
C. Wolf-Czapek,13 E. Godde,14 L. Desmarres15 all recommended the use of Eastman roll film, sensitized with dichromate and printed through the back with subsequent dyeing. Desmarres used a 1 per cent solution of dianil yellow ; and fuchsin 0.4 and eosin 0.4 per cent for the red, and the same strength of methylen blue and methyl green for the blue.
E. T. Butler16 preferred to use dyes that would not be decomposed by dichromate. and stain up before exposure, claiming that this enabled the