http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-532383-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_2b8b744d430e252fa21c14c2b8dee176 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/G11B11-00 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/G11B11-00 |
| filingDate | 1939-06-19-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1941-01-23-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-532383-A |
| titleOfInvention | Improvements in the methods of copying sound films and films for use therein |
| abstract | 532,383. Photographic sound-record films. PHILIPS LAMPS, Ltd. June 19, 1939, No. 17893. Convention date, June 21, 1938; Drawings to Specification. [Class 98 (ii)] The so-called "lens effect" which is observed i n a positive photographic copy made from a negative printed on a silver emulsion layer from a mechanically-produced sound-record film, i.e. striations in the transparent sound track due to irregular refraction of the light traversing the cut track, is avoided by either choosing for making the negative an emulsion layer of such a character, or developing a normal emulsion layer used for the negative in such a way, that the characteristic curve in the region of the blackening usually required for such records exhibits a gamma which is either a minimum or decreases with increasing exposure, and that the difference between the minimum blackening due to the "lens effect" and the bright parts is at least 0.8. The positive is printed from this negative on ordinary positive stock and developed normally. The original may be a track cut according to the variable-depth-variable-width method by a V-shaped chisel through a black coating into a gelatin layer on the film. The Specification gives and discusses several characteristic curves of sensitive material suitable for the firstmentioned method of making the negative. In one, the straight part is interrupted in the region of the usual blackening by a horizontal or nearly horizontal portion ; in another, the curve rises to a maximum in the said region and thereafter descends ; while in a third, the curve, after rising steeply at first, becomes horizontal or much less steep in the said region. The material may comprise two sensitive emulsions in super-imposed layers and of different response to a definite kind of light, the top layer may be a panchromatic or a silver bromide emulsion, and the under layer a non-panchromatic or a paper silver chloride emulsion. The layers may have the same or different gammas. Alternatively, such emulsions may be mixed in a single layer. As a further alternative, a very thin emulsion layer, less than 6 Á thick, on an antihalation substratum may be used. Development is normal in all these cases. The second-mentioned method of making the negative may be carried out by abruptly interrupting the development of the normal emulsion layer so that it is blackened only to a limited depth, using a slowed developer containing a high percentage of alcohol, glycerine, or acetone, e.g. 10 per cent., or 20 per cent. of sodium sulphite. |
| priorityDate | 1938-06-21-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 28.