A diazotype material for use in making copies of X-ray films which comprises a support carrying a light-sensitive layer containing at least one diazonium compound, a coupler and a non-light-sensitive ultra-violet absorber, the ultra-violet absorber being effective in screening out radiation in the range of 3,400 to 4,000 A, being transparent to all radiation at or above 4,300 A and being present in an amount such as to give a background absorbance of at least 0.9 at 4,000 A.
This invention relates to a recording material containing diazo compounds, in particular a microfilm, comprising a film base which is at least partially pervious to visible radiation, a light-sensitive layer and, on the reverse side of the film base, a filter layer which absorbs light in the long-wave ultraviolet spectral range and in the short-wave visible spectral range, wherein the filter layer is composed of a polymer which is insoluble or has been rendered insoluble by cross-linking, and of at least one yellow to orange-colored dye which is compatible with the constituents of the polymer and absorbs light in the range between about 360 nm and about 500 nm. The invention also relates to a process for the manufacture of a recording material.
A method of manufacturing a luminescent screen of a colour television tube in which the regions, for example dots, of the various phosphors are separated by a light-absorbing material. The light-absorbing material is provided by means of a photo-sensitive binder which is exposed to radiation through the support. The parts of the support where the phosphors are provided afterwards are first provided with a filtering layer for radiation which hardens the said binder. A layer of the photo-sensitive binder is then provided over the support which is partly covered with a filtering layer and exposed through the support. The phosphors are then provided.
The present invention relates to a two-component diazotype material comprising a support and one or several light-sensitive layers, each of which contains at least one light-sensitive diazonium salt, a coupler component and an acid stabilizer, and at least one of the layers contains a compound which absorbs light in the ultraviolet spectral region. The light-absorbing compound is present in the form of a dye salt of at least one benzothiazole which is converted into its leuco base under the action of an alkaline medium. It thus partially or completely loses its absorptivity toward radiation in the long-wave ultraviolet and short-wave visible spectral regions. The light-absorbing compound comprises a benzothiazole, in particular according to the general formula: ##STR1## wherein R.sub.1 denotes hydrogen, alkyl or aralkyl, R.sub.2 denotes hydrogen or an optionally substituted alkyl, aralkyl, aryl, pyridylalkyl, carbalkyl, carboxyalkyl, carboxyaryl, carbamoyl, or sulfamoyl radical, or R.sub.1 and R.sub.2 denote members of a heterocyclic radical, and R.sub.3 denotes hydrogen or alkyl.
Photographic element designed to prevent duplication by contact copying with actinic light, formed from a synthetic organic polymer having a nitrogen gas permeability suitable for use as a vehicle in a vesicular film, and a light sensitive diazotype composition dispersed therein in which the diazotype composition includes a light decomposable diazonium salt and a coupler for forming a dye with said diazonium salt. Upon image-wise exposure and development, the light-struck areas are vesiculated and an azo dye is formed in the nonlight-struck areas. The image formed from the vesicules relative to the azo dye provide sufficient contrast for viewing by projected light but insufficient contrast for contact copying with UV light.
The exposure latitude of positive-acting, color pre-press proofing photosensitive articles can be improved by positioning an optical filter between the separation half-tone positive and the photosensitive article.
