Patent GB-549184-A (GB)
Title: Improvements in or relating to photographic printing apparatus
IPC: G03B27/28
Filed: 1941-10-13
Abstract: 549,184. Photographic contact or projection printing apparatus. KODAK, Ltd. Oct. 13, 1941, No. 13177. Convention date, Nov. 28, 1940. [Classes 98 (i) and 98 (ii)] Marginal masking means for contact or projection-printing apparatus comprises a support provided with paper-locating means having two perpendicular edges adapted to receive a corner of a sheet of printing paper, a pair of marginal masks parallel to said edges and each adjustable on the support transversely to its own length, a margin scale connected to each mask so as to move therewith relatively to an index mark fixed in relation to the paper-locating means, and a second pair of marginal masks parallel to the first pair, and independently adjustable transversely to their length with the aid of additional scales carried by the first pair so as to complete a rectangular mask of desired size. The invention is shown as applied to a contact printing box 10 containing a printing lamp 11 and safelight 12, and provided with a clear window 14 upon which negative and printing paper may be clamped by a hinged platen 16 of the known hinged-section type having an arched handle 25 with a thumb piece 27 adapted to engage latching means 30 on the box, and an arm 32 adapted to close the printing-light switch 33 on closing the platen. Around the window 14 is a skirt 15 which, together with the interior of the box, is painted white to provide uniform illumination of the window. A plate 35 slidable to and from the top 13 of the box on posts 24 is supported on bow springs 37 and is adjustable by a screw 36 to clamp the negative in position on the window 14. Two perpendicularly intersecting edges 38, 39 on this plate serve to locate the corner of the printing paper, and the plate is so mounted with respect to the window that the paper, when so located, is masked by the window to any desired extent along the two edges adjacent to the corner. Formed in the top wall 13 of the box are two slots 401, 40 respectively parallel to the edges 38, 39 of the plate 35, and closed below by strips of translucent safelight material. Slidable in these slots are margin scales 471, 47 co-operating with index marks 511, 51 fixed on the wall 13. These scales are attached to operating members 431, 43 also slidable in the slots 401, 40, and each carrying a metal masking strip 451, 45 extending across the window 14 parallel to two edges thereof. Adjustment of the members 43<SP>1</SP>, 43 in accordance with the indications of the margin scales 47<SP>1</SP>, 47 sets the masking strips 451, 45 to give the desired margin on the two edges of the paper engaging the plate 35. To the scales 471, 47, are secured respectively scales 551, 55 also slidable in the slots 40<SP>1</SP>, 40 ; and co-operating with scales 551, 55 are pointers 591, 59 on operating members 44<SP>1</SP>, 44, similar to the members 43<SP>1</SP>, 43, which are slidable in their respective slots 401, 40, and respectively carry masking strips 451, 45 parallel to the first mentioned pair and adapted to mask the remaining two edges of the printing paper. The first pair of masking strips having been set, the second pair is adjusted in accordance with the indications of the pointers 59<SP>1</SP>, 59 on the scales 55<SP>1</SP>, 55 to complete the mask setting. To permit the apparatus to be used readily for printing narrow strip films, e.g. 35 mm. films F, the distance between the adjusting screw 36 and the left-hand post 24 is made equal to the width of the film, and film-guiding grooves are provided on the screw and post; while similar film guiding grooves are provided also on the masking-strip operating members 43, 44. When the masking means is used with projection-printing apparatus, the masking strip 451 rests above the plate 35 instead of below it as in the apparatus shown, and the printing paper rests below the masking strips instead of above them.