The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

Home | About | Photography | Contact






Negatives, Stripping of
Neomonoscope
and storage a trouble. Many use the grooved negative boxes, but while these are convenient their bulk is a great objection. A good plan is to use paper negative bags, on which can be written the subject, date, and duration of exposure, aperture of diaphragm, mode of development, and any other remarks which may be considered necessary. The negatives in the bags can then be packed close together in boxes not grooved, and they will take up about one-fourth of the room of grooved boxes. An index can be kept of them, and a list pasted inside the lid of each box for further reference. Film negatives are best kept in stiff-leaved albums, the corners being pushed into suitable slots.
Negatives, Stripping of. One of the most potent agents for removing the film from a glass plate is extremely weak hydro-fluoric acid - half a fluid drachm of the strong acid to a pint of water being sufficient. In this bath the gelatine film will soon float off the glass plate, and the film, after rinsing in water, may be received and dried on a waxed glass plate, a sheet of ebonite, or a slab of celluloid, from which it will readily separate when dry. It is, however, more convenient to purchase the more manageable fluoride of potassium or sodium, and to dissolve a dram of either in a pint of water, then to acidify by a few drops of hydrochloric acid or sulphuric acid. During the above operation the film becomes enlarged ; and if the separated film is allowed to soak for some time in water it may be readily enlarged to twice the original area, or nearly i^ linear. If, on the other hand, the film is immersed in methylated spirit, imme-diately it floats off it will be scarcely, if at all, larger than when on the original glass. Assuming the stripped film to have been floated off the original glass, and to be on the waxed glass, celluloid, or ebonite, a thick sheet of soaked gelatine may be squeegeed down upon it ; and the edges of the latter being clamped down, the whole is allowed to dry, when the negative film, strengthened by the extra thickness of gelatine, may be stripped off, and used as a reversed negative for collotype or other photo-mechanical process.
Neomonoscope. An apparatus somewhat similar to the Ale-thoscope (q.v.) and other devices of a similar kind.
472