US2331335A

US2331335A - Means for toning photographic prints

Info

Publication number: US2331335A
Application number: US368520A
Authority: US
Inventors: Alvin L Mayer
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-12-04
Filing date: 1940-12-04
Publication date: 1943-10-12
Anticipated expiration: 1960-10-12

Description

Oct. 12, 1943. A. L. MAYER 2,331,335

MEANS FOR TONING PHOTOGRAPHIC PRINTS Filed Dec. 4, 1940 INVENTOR ALVIN L. MAYER ATTO. s

Patented Oct. 12, 1943 UNITED STATES PATENT OFFICE MEANS FOR TONING PHOTOGRAPHIC PRINTS 9 Claims.

This invention relates to photographic equipment, and more particularly to a means for softening the tone of photographic prints made from dense, hard or contrasty negatives.

An object of the present invention is to provide means for flashing an auxiliary controlled beam of light onto printing paper undergoing exposure, for the purpose of softening the tone of the resultant print.

Another object of the invention is to provide means for coordinating the operating periods of the beam of flashed light relative to the density of the particular negative being printed.

A further object of the present invention is the provision of a photographic printer including novel means for toning down sharp or contrasty prints to secure a mellow characteristic, this being accomplished without regard to the type or grade of photographic printing paper used in the printer, thereby enabling the printer to be operated continuously using a single type of paper in the printing of all types of negatives.

Still a further object of the present invention is to provide selective control means for flashing an auxiliary controlled beam of light onto a sheet of printing paper prior to, during, or after the normal exposure of the printing paper to a projected, image bearing beam.

Still a further object of the invention is to provide a device of the character stated which is both structurally and mechanically simple, inexpensive and durable.

These and other objects are attained by the means described herein and disclosed in the accompanying drawing, in which:

Fig. 1 is a side view of a printing enlarging machine embodying alternate forms of the present invention, with parts thereof cut away for clarity of detail. I a

Fig. 2 is a diagrammatic view of the electrical circuit of one of the light flashing devices, embodying the present invention, of Fig. 1. I I

Fig. 3 is a vertical section on line 33 of Fig. 1 including the electrical circuit of the second flash device embodying the present invention.

The present invention is directed to the provision of means for softening the tone of photographic prints made from dense or contrasty negatives. By softening the tone of photographic prints it is possible for an operator to obtain soft, pleasing prints from dense or hard negatives when using the same type or grade of photographic paper as is used for printing other, less dense negatives.

A typical printing enlarging machine to which the present invention may be applied is illustrated in Fig. 1, wherein the numeral I0 indicates the bed of the machine, which may be supported upon leg standards II. A projector I2, including a source of illumination, such as electric lamp I3 is shown mounted on the left end of the bed for projecting the image of a negative mounted laterally within gate I l, through projection lens I5 onto a sheet of sensitized photographic printing paper disposed in gate I6 of a paper support I! suitably mounted to bed I0.

A shutter for lens I5, denoted generally by the numeral I8, may be provided for controlling the time period during which the printing paper is exposed to the image bearing projection beam during the printing operation. Said shutter may include a trip lever I9 which may be actuated, for operating the shutter, by means of a connector 30, the lower end of which is operatively secured to rock shaft 3I, which in turn is operatively connected to foot treadle 32 by link 33, as illustrated.

Inasmuch as the individual densities of the negatives, the images of which are projected onto paper mounted in gate I6, differ haphazardly from very light to very dense, suitable means may beprcvided for standardizing the density of the image bearing beam projected from the negatives regardless of their individual density. One form of such projected light control means may comprise,.by way of example, a diaphragm plate 20 swingedly mounted between projection lens I5 and shutter I8.

As disclosed in Fig. 2 diaphragm plate 20 may comprise an apertured portion 2 I, the width of which progressively decreases from a maximum at the outer end 22, to a minimum at the inner end 23. The lower end of said plate may be secured to and carried by an auxiliary shaft 24, which may be suitably mounted to bed III for rotation about its longitudinal axis. This shaft may be actuated by means of a handle 25- or the like, for shifting diaphragm plate 28 relative to and across the optical axis of projection lens I5 for selectively controlling the eifective aperture size of the lens.

The amount by which the projection beam from lens I5 is modified for a particular negative undergoing projection, depends upon, and is a function of the density of the particular negative being projected. The effective aperture size of the projection lens may, for each negative, be determined either by the judgment of the operator, or by. mechanical means responsive to the intensities of the light from lamp l3 as modified by the particular negative placed in gate I4. It may be generally stated that the efiective aperture size of the projection lens is varied inversely to the intensity of the beam entering the projection lens, wherefore it becomes apparent that for a dense negative the effective aperture size of the projection lens will be modified a very small amount, if at all. Conversely; for negatives of a lesser density, that is, thin or light negatives, the amount by which the intensity of the light entering the lens is reduced for projection, is much greater. With reference to 2, the reference line A-A indicates, by way of example, that portion of diaphragm aperture 2| which will be aligned with the optical axis of pro jection lens l5 for a negative having an average density. Therefore, when a dense negative is being projected the diaphragm plate will be shifted. relative to lens It so as to dispose those portions of aperture 2! between ends 22 and line A -A before the lens for obtainingv a relatively large effective aperture size of said lens. By the same token, negatives having a lesser density than the so-called idea]. or average negative will necessitate aperture. 2| being aligned with lens so as to dispose its narrower portions, between line A-A and end 23, before the lens.

The means employed for softening the tone of photographic prints made from dense or hard negatives may comprise an auxiliary illumin-ato-r 40, which may be in the form of a small spotlight aimed at the print, or if preferred, provision may be made for utilizing part of the projection beam for that purpose. The arrangement for use of the auxiliary, or tone-softening illuminator, is such that its light rays are controlled by means of a timing device which, in turrn is rendered operative and inoperative to close an electric circuit to the auxiliary illuminator in accordance with movements of' the diaphragm plate relative to the optical axis of lens I5.

This control arrangement is clearly illustrated in: Figsql and 2- wherein an auxiliary illuminator 40 is shown mountedv upon the projector barrel or housing 4|. As previously explained, rock shaiitmay be actuated by handle 25 for aligning the proper portion of diaphragm plate aperture 2! with the optical axis of lens I5, depending upon the nature of the negative to be printed, for standardizing the intensity of the image bearing projected beam. As hereinabove stated, the image bearing projection beam emanating from lens [:5 will be relatively unrestricted when dense or hard negatives are being projected. This means. that only those portions of the diaphragm aperture 21 to the right of reference line- A--A will. be placed. in register with lens [5.

It will, therefore, be understood that when dense or contrasty negatives are being projected, the projected images thereof will withstand a limited amount of controlled illumination by the rays from the auxiliary illuminator 48. Such auxiliary rays have a softening or mild fogging effect upon the paper being printed, as well understood by those versed in the art. It is important, however, that the duration of time during'which these toning rays are projected onto the printing paper, be accurately controlled. Experience demonstrated that such auxiliary rays should. not be used in the printing. of light negatives, that is, when printing negatives whereinthat portion. or a erture 21' of diaphragm plate 20 to the left of reference mark AA is in register with the projection lens. Accordingly, means are provided for automatically rendering the auxiliary illuminator inoperative upon movement of the diaphragm plate 2!] beyond, by way of example, that portion of aperture 2| located to the left of reference point A-A.

Such means may consist of a selector switch 42 which includes a movable contactor arm 43, which is operatively secured to and carried by shaft 24, and a fixed or stationary contact 44 mounted to bed H] as clearly disclosed in Fig. 2. Contact 44 comprises a conductor segment 45 and. an. insulator segment 46. During those pe ri'od's of time when diaphragm plate 29 is disposed with that portion of aperture 2! to the right of reference point A--A aligned with the optical axis of lens l5, contactor arm 43 will be in closed circuit relationship with the conductor segment 45 of contact 44. As shaft 24 is rocked in a clockwise direction for aligning various portions' of aperture 2! between ends 22 and reference line A-A relative to the projection lens, the movable contactor arm 43 will continue to engage the conductor segment 4-5 of the contact block. Further clockwise rotation of shaft 24 will cause contactor arm 43 to engage the insulator segment 46 of contact M as those portions of aperture 2! disposed to the left of line A.--A are aligned with the lens.

The conductor segment 45 of contact M may be connected by conductor 51' with one side of bulb 48 of the auxiliary illuminator 46. Conductor 49 connects the other side of bulb 48 to line H of any suitable source of electricity. A conductor 50 connects the other line m of the source or electricity to one side of a suitable timer device denoted generally by the numeral 5|, the other side of which timer is connected by a conductor 52 to a movable contact element 53' carried by swinging contact arm 54 carried by and secured to rock shaft 3i. Contact 53 is adapted to engage a fixed contact 55, mounted to bed Iii by bracket I55, when shaft 31 has been actuated, via foot treadle 32, to operate shutter [9. Conductor 56 connects contact 55 with contactor arm 43.

The timer device 5| may be of any approved or accepted type capable of maintaining a closed electrical circuit for a definite, predictable period of time. Such timer is preferably provided with suitable means for permitting various timing cycles to be set on said device.

From the foregoing, it will be evident that when foot treadle 32 is depressed, rock shaft 3! will be rotated about its longitudinal axis for causing contact element 53 to engage contact 55. If contactor arm 43 is in engagement with the conductor segment 45 of contact block 44, an electrical circuit to lamp 48 will be closed and simultaneously therewith a timing cycle will be initiated in timer 5!, with the result that the auxiliary illuminator 40 will be energized for casting its light rays upon the photographic paper undergoing printing. Upon the expiration of such a timing cycle, or upon release of foot treadle 32,

whichever occurs first, the electrical circuit to lamp 48 will be broken and the flashing or toning period will be terminated. It will be noted that energization of the auxiliary illuminator 40 is possible only for those positions of diaphragm plate 20 between reference mark AA and the outer ends 22, that is, when the maximum amount of projected light is permitted to be projected from lens l5 onto the printing paper. In other words, when the diaphragm plate 29 is moved for registering that portion of aperture 2| to the left of reference point A--A relative to the optical axis of lens [5 the electrical circuit of the auxiliary illuminator will bebroken at selector switch 42.

With reference to Fig. 3 and to the left end of projector 12 of Fig. 1 a second, or alternate type of means for coordinatingthe operating periods of auxiliary illuminator 4| relative to the density of the negative being projected is illustrated. Such means may comprise a movable diffuser plate 80 disposed between condenser unit ill and film gate H as shown. The essential characteristic of diffuser plate 80 is to uniformly reduce the intensity of the light beam leaving the condensers 8| prior to passage through a negative mounted in gate l4 during those periods of time when the image of a thin or light negative is being projected onto paper mounted in support II. If desired, diffuser plate 80 may comprise a ground glass disk 82, Fig. 3, which may be suitably mounted within a circumscribing rim 83.

As clearly disclosed in Fig. 3, a diffuser plate 80 is adapted to be disposed in either of two normal positions, viz, in a lowered beam intercepting position B, or in a raised non-intercepting position C. If desired, rim 83 may include an arm 84 pivotally mounted to the projector housing as at 85. The outer end 86, of arm 84 may be operatively connected to an actuator lever 81 by a connecting rod 88. Actuator lever 81 may be pivotally secured, as at 90, to support bracket 89 which may be secured to, and carried by bed III. This construction enables an operator to swing diffuser plate 89 upwardly from position B to position C by lifting upwardly on actuator lever 81 at 9|, as indicated by the broken lines.

It should be understood that diffuser 80 will be disposed in its lowered beam intercepting position B during those periods of time when a light or thin negative is mounted in gate M, the image of which is projected onto the printing paper. It should likewise be understood that diffuser 80 will be disposed in its raised non-intercepting position during the projection of dense, or contrasty negatives, the projection of which requires a maximum beam intensity. As hereinabove pointed out, it is highly desirable to soften the tone of photographic prints made from dense, hard or contrasty negatives, therefore, means are providedfor completing an electrical circuit to the auxiliary illuminator 40 whenever diffuser plate 80 is raised upwardly to its beam non-intercepting position C. With reference to Fig. 3 such means may comprise an electric switch denoted generally by the numeral 92, including a projecting switch-actuator-arm 93, which is adapted to be lowered for completing an electric circuit to illuminator bulb 48 when contacted by stop member 94 carried by rod 88. It should be understood that conductor 95 may be provided for establishing an electrical connection between the one side of switch 92 and one side of illuminator bulb 48, and that a second conductor 96 may be provided for connecting the other side of said bulb to one side of an electric supply line H. The other side of switch 92 may be connected by means of conductor 91 to one side of a timer device, denoted generally by the numeral the other side of which timer may be connected by conductor 98 to contact point 99, which is adapted to be connected to the other side of electric line 10 when movable switch arm 64 has been closed.

From the foregoing it is apparent that the auxiliary illuminator 40 will be energized only during those periods of time when diifuser plate has been lifted to position C incident to the projection of the image of a dense, hard or contrasty negative.

In order to obtain maximum flexibility of the auxiliary illuminator 40, means are preferably provided for rendering the operating characteristics of said illuminator either automatically operable, manually operable or non-operable. Such means may comprise a four-way switch 60, including four spaced contact points such as 6|, 62, 63 and 99, and a movable selector arm 64. Conductor 59, Fig. 2, may terminate in contact point 63, whereas one end of movable selector arm 64 may be continually connected with lead 70 of the pair of leads 10 and H of the electrical supply line. During those periods of time when movable selector arm 64 is swung so as to engage contact 63 the automatic operation of the illuminator hereinabove described relative to Fig. 2 may take place.

In order to permit manual control of auxiliary illuminator 40 means are provided for electrically disconnecting that portion of the electrical circlL't from the timer 5| to conductor 41, and for placing key 65 in the circuit. Key 65 may include a stationary contact point 66 electrically connected to conductor 41, and a movable contact point 61 which is electrically connected to contact point 6 I. When selector arm 64 is moved to engage contact point 6| the auxiliary illuminator may be energized whenever key 65 i manipulated by an operator regardless of the setting of diaphragm plate 20. In order to render the auxiliary illuminator #0 non-operative the movable selector arm 64 may be swung to engage contact point 62, which comprises a neutral point. In order to render the auxiliary illuminator control means of Fig. 3 operative selector arm 64 may be swung to engage contact point 99.

It should be understood that the auxiliary illuminator 48 may be supported upon the machine at any convenient location from which its light rays may be projected onto the sensitized photographic paper to be exposed to the image of a negative supported within film gate l4, Fig. 1. Experimentation has demonstrated that satisfactory results may be obtained when the toning rays of the auxiliary illuminator are directed onto the rear, as well as the front of the sensitized printing paper, therefore, if desired an auxiliary illuminator may be suitably mounted as at I40 to the rear of paper support II, as illustrated. It

i should be understood that when the auxiliary illuminator is positioned as at I40, so that its toning rays fall upon the rear, non-sensitive side of the printing paper, the rear portion of paper support I! must necessarily be open. In some instances it may be desirable to utilize both auxiliary illuminators M3 and E49 whereby to permit a simultaneous flashing of the front and rear surfaces of the photographic printing paper mounted in gate US.

By providing such auxiliary illuminators, it will be found possible to eliminate the necessity for utilizing several grades or types of sensitized printing paper in the production of photographs. The use of different grades or types of printing paper was heretofore necessary due to the fact that the projected images from a single roll of film would vary inversely with the densities or contrast characteristics of the individual negatives comprising said film. The operator of the printer was heretofore required to select the proper type or grade of printing. paper for each negative being projected depending uponits individual density. The necessity for such a selectionof printing paper is eliminated by the present device, first, by means of diffuser plate 80, or the diaphragm plate 2-8 which permits the intensity of the projected image, bearing beam from the various negatives to be standardized, regardless of the particular density of the individual negative being projected, and secondly, by means of the auxiliary illuminator which softens the tone of those photographic prints made from dense or contrasty negatives. By means of the auxiliary illuminator of the present invention it is possible to tone down and soften the prints made from, dense negatives, except when the dense negative to. b printed is a so-called stain negative. When a stain negative is to be printed it is preferable, though not essential, for an operator to substitute a special hard grade photographic printing paper for the standard grade being used for printing all other types of negatives.

The duration of the toning light or flash may bereadily varied to meet the, particular conditions arising from time to time, by suitably adjusting pointer l2 of timer 5i for controlling the duration of the timing cycle.

It should be understood that while the printer of Fig. l is provided with both types of control means of Figs. 2 and 3, in actual practice but one or the other would be used. In those instances when it is desired to flash the printing paper prior to, or after exposure, key 65 may be used to advantage.

It is to be understood that various modifications and changes in the structural details of the present device may be made, within the scope of the appended claims, without departing from the spirit of the invention.

Whatis claimed is:

1. In a photographic device, a film support, a paper support, a projection lens and a source; of light for projecting the image of a negative mounted in said film support onto paper mounted on said paper support, a shutter for said lens, an auxiliary illuminator for projecting an auxiliary beam of; light onto said paper, a timer for con trolling the operating characteristics of said illuminator, and means operable for simultaneously operating said shutter and initiating a timing cycle in said timer whereby the beam from said auxiliary illuminator will be projected onto the printing paper coincident with the image bearing; beam.

2. In a photo-graphic device, a film support, a paper Support, a projection lens, a source of light for projecting the image of a negative mounted in the film support onto a sensitized. printing paper mounted on the paper support, a shutter for said lens, a diaphragm for said lens for controlling the effective aperture size of said lens with regard to the density of the particular negative being projected, an auxiliary illuminator for projecting a beam of light onto said paper, a timer for controlling the operating period of said illuminator, means for synchronizing the opening of said shutter with the initiation of a time cycle; in said timer, and means for rendering said illuminator operable and inoperable dependent upon the effective aperture size of said lens for the particular negative being printed.

3. In a. photographic device of the character described, the combination of a film support, a paper support, projection means including alight beam to project the image of a film heldby the.

film supportponto a photographic paper sup.- ported by said paper support, and a controlled source of light projectable onto the photographic paper additional to the beam light projecting the image, for softening the tone of the resultant print, the control for said tonesoftening light comprising an apertured diaphragm movable across the optical axis of the lens. for controlling, the intensity of the projected beam and means coordinated with the movements. of said diaphragm for rendering the tone-softening light source inoperative upon the photographic paper when the diaphragm is in posiiton to intercept a substantial part of the projection beam.

4. In a photographic device of the character described, the combination of a film support, a paper support, projection means including a l ght beam to project the image of a film located, in said film support, onto photographic paper supported by said paper support, a. difiuser plate for controlling the quantity of light passing through said film in accordance to its density, said diffuser plate having but two normal positions, one in a lowered beam modifying position, the other in a raised beam non-intercepting position, an auxiliary illuminator for projecting an auxiliary beam of light onto said paper in addition to the image bearing projected beam, and means for rendering said illuminator operable and inoperable dependent upon the position of said difiuser plate. during the projection of the particu lar negative being printed.

5. In a photographic device, a film support,

7 a paper support, a projection lens. and a source of light for projecting the image of a negative mounted in said film support onto paper mounted on said paper support, a shutter for said lens, an auxiliary illuminator for projecting an auxiliary beam of light onto. said paper, means. for correlating the operating characteristics of said illuminator relative to the intensity of the image bearing beam, and means for synchronizing said last mentioned means with said shutter whereby an auxiliary beam from said illuminator willv be projected onto said paper coincident with and for a length of time not exceeding the exposure initiating a timing cycle in said timer whereby the beam from said auxiliary illuminator will be projected onto the printing paper coincidentwith the image bearin beam. I

7. In a photographic device, a film support, a paper support, a projection lens and a source of light for projecting the image of a negative mounted in said film support onto paper mounted on said paper support, a shutter for said lens, an auxiliary illuminator mounted to. the rear of said paper support for. projecting an auxiliary beam of light onto the rear unsensitized surface of said paper, a timer for controlling the operating characteristics of said illuminator, and means operable for simultaneously operating said shut.- ter and initiating a timing cycle in said timer whereby the beam from said auxiliary illuminator will be projected onto the printing paper coincident with the image bearing beam.

8. In a photographic device, a film support, a paper support, a projection lens and a source of light for projecting the image of a negative mounted in said film support onto paper mounted on said paper support, a shutter for said lens, a pair of auxiliary illuminators mounted one in front of and one to the rear of said paper support for simultaneously projecting an auxiliary beam of light onto the front and rear surfaces of said paper, a timer for controlling the operating characteristics of said illuminators, and means operable for simultaneously operating said shutter and initiating a timing cycle in said timer whereby the beam from said auxiliary illuminators will be projected onto the printing paper coincident with the image bearing beam.

9. In a photographic device of the character described, the combination of a film support, a paper support, projection means including a light beam to project the image of a film held by the film support, onto a photographic paper supported by said paper support, and a controlled source of light projectable onto the photographic paper additional to the light beam projecting the image, for softening the tone of the resultant print, the control for said tone softening light comprising an apertured diaphragm movable across the optical aXis of the lens for controlling the intensity of the projected beam and means coordinated with the movements of said diaphragm for rendering the tone-softening light source inoperative upon the photographic paper when the diaphragm is in position to intercept more than a predetermined portion of the projected beam.

ALVIN L. MAYER.