http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-626998-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_9799ffcda2dbb45041a5ab0fd08dd5fe |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/G03C5-305 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/G03C5-305 |
| filingDate | 1947-03-14-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1949-07-25-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-626998-A |
| titleOfInvention | Improvements in photographic developers |
| abstract | 626,998. Photographic developers. KODAK, Ltd. March 14, 1947, No. 7198. Convention date, March 14, 1946. [Class 98 (ii)] A photographic developer comprises a strong inorganic base such as caustic soda, a developing agent such as pyrogallic acid, hydroquinone, monomethyl p-aminophenol or glycin, and a mixture or addition compound of cyclohexanone or a substituted cyclohexanone such as p-methyl cyclohexanone with a soluble sulphite or bisulphite. The cyclohexanone bisulphite compounds are believed to undergo a partial hydrolysis in solution, yielding a supply of sulphite ions to replace those oxidised by the atmosphere and so permit production of a strongly alkaline developer such as one of pH over 12, but which has a low sulphite ion concentration and is suitable for maximum contrast or tanning development and yet is not readily darkened by oxidation. To form the mixture or addition compounds sodium or potassium sulphite or metabisulphites may be used and to reduce further the sulphite ion concentration an excess of cyclohexanone is desirable. The description enumerates the superiority of developers made according to the invention over similar developers which incorporate acetaldehyde-, acetone-, methyl ethyl ketone-, and ethylacetoacetatebisulphite compounds as regards prevention of atmospheric darkening, and specifies a developer which gives as much contrast as one containing 1 gram of sodium sulphite per litre, but which oxidises as slowly as one containing 5 grams of sulphite per litre. The use of formaldehyde bisulphite compounds in developers is also mentioned. |
| priorityDate | 1946-03-14-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 42.