The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 14, 1989
Filed:
Sep. 18, 1987
Richard J Brent, Handforth, GB;
Brian F Moss, Chelford, GB;
Ciba-Geigy AG, , CH;
Abstract
There is described a method of determining the contrast grade of the paper to be used to print a black and white photographic negative which comprises placing a photocell in the darkest significant area of a projected negative image and noting an indication of the light received or calibrating the photocell so when the photocell receives light of the same level it will indicate this, then placing the photocell in the lightest significant area of the projected image of the negative and reducing the light reaching the photocell using graduated steps until the light reaching the photocell is of the same level as the light which reached the photocell when it was placed in the darkest significant area of the projected negative image and noting the step employed to achieve this equivalence and selecting the contrast grade of the paper which is indicated by the step which achieved equivalence. The method can be performed using an enlarger or by use of a modified light exposure meter.