US2992592A

US2992592A - Masking frame for making enlargements

Info

Publication number: US2992592A
Application number: US685830A
Authority: US
Inventors: Westendorp Hans
Original assignee: Agfa AG
Current assignee: Agfa Gevaert NV
Priority date: 1956-10-18
Filing date: 1957-09-24
Publication date: 1961-07-18
Anticipated expiration: 1978-07-18

Description

July 18, 1961 H. WESTENDORP 2,992,592

MASKING FRAME FOR MAKING ENLARGEMENTS Filed Sept. 24, 195'? .INVENTORS.

HANS WES TENDORP ATTORNEY? United States Patent 2,992,592 MASKING FRAME FOR MAKING ENLARGEMENTS Hans Westendorp, Opladen, Germany, assignor to Agfa Aktlengesellschaft, Leverkusen, Germany, a corporation of Germany Filed Sept. 24, 1957, Ser. No. 685,830 Claims priority, application Germany Oct. 18, 1956 Claims. (Cl. 88-24) This invention relates to a masking frame for making enlargements, the frame having adjustably movable enlargement masking strips and an adjustable angular abutment bearing an angle-shaped masking member which maintains its position, for the purpose of producing white margins of uniform width on prints made on any desired paper sizes. The novel feature of the invention is that the movable enlargement masking strips are provided with stop bars which are fixedly, resiliently or ad justably arranged on the strips. The stop bars cause photographic paper laid in the frame to be aligned in the direction towards the middle of the picture upon moving the masking strips and to be shifted towards the angle stop until the fixed enlargement angle frame borne by the fixed angle stop and the movable masking strips cover the margins of the paper sheet to a constant width on all sides, so that subsequent trimming of the edges of the picture is unnecessary.

To allow occasional checking of the position of the sheet of photographic paper positioned in the masking frame, the stop bars can be provided with incisions and the masking strips can be provided with closable apertures at the places above the incisions.

One embodiment of the invention is shown diagrammatically in the drawing, FIG. 1 being a cross-sectional view of the enlarging masking frame and FIG. 2 a plan view thereof. In the figures, 1 represents an adjustable precision angle stop, 2 is an enlargement angle mask borne by the angle stop, 3 is a paper supporting plate and 4 and 5 are movable masking strips. These masking strips 4 and 5 are provided with stop bars 6 which are arranged on the underside of the strips at a distance of 3 mm. from the edges of the strips. To allow the abutment of the paper to be checked, the stop bars 6 are formed with incisions 7, above which are disposed apertures 8 in the masking strips 4 and 5. These apertures can be closed against incidence of light during the exposure by means of spring-loaded flaps 9. Rotatable knobs 10 are provided for moving and adjusting the masking strips 4 and 5. When the adjustable paper angle stop 1 is adjusted to a margin width of 3 mm., it must be spaced exactly 3 mm. from the inside edge of the enlargement angle mask 2. If series production giving such accuracy consistently is not possible, provision must be made for subsequent adjustment of the stop member 1.

In the embodiment proposed here, when the masking frame is closed, the angle mask 2 must leave a space of the order of size of a sheet of photographic paper of the thickness of card between the base plate 3 and the mask 2 so that the paper to be exposed can be aligned by the stops and displaced against the stop angle member 1, to ensure margins of uniform width on all sides are obtained.

The working procedure is as follows: The paper stop 1 is adjusted to a margin width of 3 mm. The paper to be exposed is pushed against the angle stops in the usual Way and the masking frame is closed.

Using the rotatable knobs 10, the masking strips are moved a few millimetres outwards and then inwards.

The stops 6 of the masking strips 4 and 5 abut against 7 the outside edges of the paper and push this tightly against the angle stop 1, so that it is simultaneously aligned.

"ice

If the masks 5 are displaced a few millimetres towards the middle of the picture during the closing operation, for example by resilient bell crank levers, the movable masks 4 and 5 have only to be adjusted according to a scale index for the picture sizes. These masks are then automatically pushed towards the edges of the paper and, in a continuation of this movement, they press the paper in an aligned position against the angle stops 1, so that margins with a uniform width on all sides are obtained.

I claim:

1. A masking frame for use in enlarging comprising a paper supporting surface, first stop means positioned along two adjacent sides of said supporting surface adapted for guiding abutment of corresponding adjacent edges of a sheet of photographic paper positioned on said surface, an angle mask member disposed along said adjacent sides above said stop means and inwardly extending a predetermined distance past the inward edge of each of said stop means, two adjacent movable masking strips disposed along the opposite sides of said supporting surface, said strips being provided with second stop means secured along their undersides and spaced from the inward edges of said strips a predetermined distance, said angle mask and said strips being positioned with respect to said supporting surface to allow a sheet of photographic paper to be slid therebetween in contact with said second stop means, means for moving said strips toward and away from the opposite angle mask, whereby a sheet of paper placed on said surface can be aligned by said second stop means and displaced against said first stop means during movement of said strips toward the opposite angle mask thereby ensuring margins of uniform width on all sides of the paper to be exposed.

2. A masking frame according to claim 1 wherein said second stop means are provided with incisions defined therein, said masking strips are provided with apertures defined therein, said apertures being disposed directly over said incisions, and means are provided for preventing the passage of photographic exposure light through said apertures.

3. A masking frame according to claim 1 wherein means are provided for adjusting the predetermined distance said second stop means are spaced from the inward edges of said strips and the predetermined distance said angle mask member extends past the inward edge of said first stop means.

4. The improvement according to claim 2 wherein said means for preventing the passage of photographic exposure light through said aperture comprises means for opening and closing said aperture.

5. A masking frame according to claim 1 wherein said second stop means are provided with stop inward edges spaced from the inward edges of said strips a predetermined distance and perpendicular to the plane of said strips.

References Cited in the file of this patent UNITED STATES PATENTS 1,303,418 Tornsjo May 13, 1919 1,811,123 Glaser June 23, 1931 2,412,507 Hunter Dec. 10, 1946 2,418,226 Half Apr. 1, 1947 2,523,669 Schleimer Sept. 26, 1950 2,544,883 Isaac et al. Mar. 13, 1951 2,848,923 Diefenbach Aug. 26, 1958 FOREIGN PATENTS 31,978 Austria Feb. 25, 1908 565,015 Germany Nov. 25, 1932 277,046 Switzerland Nov. 1, 1951