Black and white paper with variable gradation
AssigneeAgfa-Gevaert
InventorsManfred Peters, Thomas Kaluschke, Hans Ohlschlager, Bruno Mucke
Life of this patent
Estimating the term…
Abstract
A black & white paper with variable gradation containing a silver chloride-bromide emulsion, which is divided into at least three portions, one of which is sensitised with a blue sensitiser and two further portions are sensitised both with differing quantities of blue sensitiser and with differing quantities of a green sensitiser, wherein the blue sensitiser is of the formula (I) and the green sensitiser is of the formula (II) ##STR1## in which R.sub.1 to R.sub.8, X.sup.(-) and m have the meaning stated in the specification, is distinguished by an extended gradation range.
Claims4
Black & white paper with variable gradation which comprises a silver chloride-bromide emulsion which is divided into at least three portions, one portion is sensitized with a blue sensitizer and two further portions are sensitized both with differing quantities of blue sensitizer and with differing quantities of a green sensitizer, wherein the blue sensitizer is of the formula (I) and the green sensitizer is of the formula (II)
- in which
- R.sub.1 means alkyl, alkenyl, aryl or aralkyl,
- R.sub.2 and R.sub.3 mutually independently mean hydrogen, alkyl, alkenyl or aryl or together mean the remaining members of a 5 to 7 member ring which can further contain a further hetero atom,
- R.sub.4 means hydrogen, halogen, alkyl, alkoxy or aryl,
- R.sub.5 and R.sub.6 mutually independently mean alkyl, carboxyalkyl or sulpho-alkyl,
- R.sub.7 means alkyl, hydroxyalkyl or acyloxyalkyl,
- R.sub.8 means halogen, CN or CF.sub.3,
- R.sub.9 means hydrogen, halogen or CF.sub.3
- X.sup.(-) means an anion and
- m means 0 or 1, wherein m means 0 if at least one of residues R.sub.5 and R.sub.6 means sulphoalkyl.
Dependencies are inferred from the claim text.