GB2145843A

GB2145843A - Photographic distortion apparatus

Info

Publication number: GB2145843A
Application number: GB08419008A
Authority: GB
Inventors: Bryan Stringer; Paul Cobby
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-07-27
Filing date: 1984-07-25
Publication date: 1985-04-03
Also published as: GB8320265D0; GB2145843B; GB8419008D0; DE8422042U1; DE3427242A1

Abstract

Photographic distortion apparatus including a lower film support member 3 having a substantially flat surface and mounted for reciprocating linear movement in predetermined directions 33 parallel to said flat surface, a transparent upper film support member 14 located above the lower support member and having a substantially flat surface parallel to the flat surface on the first member and mounted for recipocating linear movement in predetermined directions 40 parallel to its flat surface and normal to the direction of movement of the first member, and means for driving said first and second support members to cause said movement and means for simultaneously varying the stroke of each member. The support surfaces are constrained to move linearly and are engaged by an adjustable rotating cam. A photosensitive film is placed on one support and an original placed on the other. The supports are reciprocated during exposure to provide a line around the image. <IMAGE>

Description

SPECIFICATION Photographic distortion apparatus This invention relates to photographic distortion apparatus of the kind used in the preparation of finished art work in the graphic arts industry, in particular the mechanical process of producing "tone line conversion".

In the graphic arts field, the conventional method of producing a "line conversion" or a line running around an image, has been by one of two methods: (1) hand drawing by a graphic artist; (2) acetate spacing, using a spacing sheet of film between a negative and positive film of an original, then exposing the film from an angle of 45 whilst rotating the film on a contact frame, thus enabling a light to spread through between the negative and positive to produce a line OR by offsetting the negative and positive to produce a strong line bias or drop shadow effect; (3) previously disclosed photomechanical systems whereby photographic negatives and positives are moved in a predetermined path to allow light to pass between them onto a piece of unexposed film, thereby creating the desired effect, for example of the kind shown in U.S. Patent Specification No.

2 286 883.

These are the three recognised methods currently employed.

The problem with the first method is that it takes a very experienced artist many hours to produce an end result and the quality of the finished artwork can vary enormously with the skill of the artist, ie. uneven line weight, ragged lines. The problem with the second method, the photographic method, is that it is very unreliable. An experienced person can reasonably produce a good result but cannot work to any tolerance (line weight), sharp edges on artwork flatten out, and lines in close proximity bleed (infill) together. The problem with the third method is that previous equipment available is not accurate enough and requires a great skill to master, and requires a large number of intermediary film stages to produce an end result.

From a practical point of view, it is required that the industry can produce from supplied artwork (line or tone) a line rendering to an accurate measurement very simply and quickly. This is particularly desired from a toned original where a "key line" is needed to highlight certain toned changes in the photograph. In addition, it is aesthetically desirable to produce a shadow effect on the image.

The present invention is intended to overcome some of the problems.

According to the present invention photographic distortion apparatus includes a lower film support member having a substantially flat surface and mounted for reciprocating linear movement in predetermined directions parallel to said flat surface, a transparent upper film support member located above the lower support member and having a substantially flat surface parallel to the flat surface on the first member and mounted for reciprocating linear motion in predetermined directions parallel to its flat surface and normal to the direction of movement of the first member, means for driving said first and second support members to cause said movement and means for varying the stroke of each member.

It has been found that apparatus of this kind is capable of producing very accurate work.

Preferably the means for varying the stroke acts simultaneously on both support members.

In a preferred construction the drive means acts to tend to impart an orbital relative movement to the support members which is translated into reciprocating movement of each support member by guide means.

One support member can carry a rotatable cam which acts on the other support member to tend to impart said relative orbital movement.

Conveniently the means to vary the stroke of the support members can be provided by means for adjusting the throw of the cam and with this arrangement said cam can be arranged to rotate about an axis which is fixed in relation to said lower support member.

Preferably means are also included for causing substantially relative linear movement between the support members in a predetermined direction so that "shading" to one side of a design can be achieved.

The means for causing said relative linear movement between the support members in a predetermined direction can also be provided by the means for altering the throw of the cam.

Means may be included for locking the cam adjustment means at different throw positions, and which when locked causes operation of the drive means to impart said reciprocating movement of the support members, and which when unlocked causes substantially relative linear movement between the support members in a predetermined direction.

Manually operated means can also be included for causing relative linear movement between the support members in a predetermined direction.

The invention can be performed in many ways but one embodiment will now be described by way of example and with reference to the accompanying drawings in which Figure 1 is a cross-sectional diagrammatic view of apparatus according to the invention; Figure 2 is a cross-sectional view on the line ll-ll of Figure 1; Figure 3 is a plan view of the apparatus shown in Figures 1 and 2 with parts of the lower support member cut away; and, Figure 4 is a cross-sectional view of the drive mechanism.

As shown in the drawings the apparatus comprises a base 1 having side walls 2.

Mounted for movement relative to the base is a lower film support member 3 on which is carried a glass sheet 4 to which the film can be attached. The film support member 3 has a substantially flat surface and is mounted for reciprocating linear movement in predetermined directions parallel to said flat surface in a manner to be described. Located above the lower support member 3 is a transparent upper support member 5 made from suitable synthetic plastics material. In Figure 1 this sheet is shown in a raised position but in use it would be closely above or in contact with the glass sheet 4.This upper support member 5 also has a substantially flat surface parallel to the flat surface on the member 3 and is again mounted for reciprocating linear movement in predetermined directions parallel to its flat surface but, in this case, the directions are substantially normal to the direction of movement of the member 3.

The drive means for causing movement of the support members 3 and 5 is shown in more detail in Figure 4 and comprises an electric motor 7 which drives an adjustable cam 8 through a drive spindle via suitable gearing 10. As shown in Figure 5 the motor 7 is secured to a carrier memeber 11 by means of a frame 1 2. The carrier 11 is substantially circular and is connected to the lower support member 3. The adjustable cam 8 is also circular and is connected through a roller bearing 1 3 to a mounting 14 for the upper support member 5. The upper support member 5 is arranged so that it can easily be removed from the mounting 14 or it can be pivoted to it so that it can be raised and lowered.

The adjustable cam 8 is provided with a screw threaded shaft 1 5 carried in bearings 1 6 within which it can freely rotate. The motor drive shaft 9 carried a bevel gear 1 7 which engages a further bevel gear 1 8 which is screw threaded onto the shaft 1 5. An upper bevel gear 1 9 meshes with the gear 18 and is mounted on a spindle 20 which is connected to a "dial pod" 21. The dial pod comprises an operating member in the form of knob 22 to which the spindle 1 9 is connected through a releasable lock 23 and the mechanism includes a revolution counter (not shown) arranged through suitable gearing so that the number of revolutions applied to the knob 22 is indicated.Devices of this kind are well known in themselves and it will not therefore be described further. Knob 22 acts to effectively prevent rotation of spindle 20 when locked by lock 23 to a cover plate 24 on which the dial pod 21 is located to which it is secured by screws 25 which extend downwardly to a location member 26 carried on bearings 27 in the carrier member 11.

Thus, with the lock 23 unlocked the bevel gears 1 7, 1 8 and 1 9 are free to rotate and if the operating knob 22 is rotated the drive causes the bevel gear 1 8 to rotate to cause the threaded shaft 1 5 to move appropriately through the gear carrying with it the remainder of the cam 8. The cover plate 24 carries an appropriate direction indicator and scale around its edge so that the direction of linear movement of the cam can be adjusted either by locking the knob 22 and operating the drive motor or by manually rotating the cam and cover plate 24 which is provided with projecting studs 24a to assist rotation.The linear movement of the cam is transferred to the upper support member 5 and thus there is linear movement in a desired direction in relation to the lower support member.

If desired the electric motor 7 can be operated to achieve the linear movement by switching it on and again switching it off when the appropriate movement has been achieved. During this movement the operating knob 22 will of course rotate and the amount of movement will be indicated on the scale.

Thus it will be appreciated that the throw of the adjustable cam 8 can be easily adjusted manually or by operation of the motor 7 with the lock 23 released.

When the lock 23 is operated this effectively prevents rotation of the shaft 20 and the bevel gears. If the electric motor 7 is now operated the shaft 9 will rotate carrying with it the cam 8 which is now locked to it. Rotation of the cam will thus cause relative orbital movement between the upper support member 5 and the lower support member 3 if they were not suitably restrained and guided.

The support members 3 and 5 are located on the base 1 so that they are restrained to movement in linear directions normal to each other. The lower support member 3 is connected through members 28 secured to its lower surface to control guide rods 29. These extend across the width of the base and are secured at one end to one of the walls 2 by members 30. The central rods 29 are connected to members 28 and 30 by means of flexible wires 31. The lower surface of the lower support member 3 is supported on bearing rollers 32 which are mounted on the floor of the base 1 in the manner shown in Figures 1, 2 and 4. The support member 3 can therefore reciprocate in a substantially linear direction in the direction shown by arrow 33 in Figure 1 moving on the roller bearings 31 but being restrained from movement in a direction normal thereto by the wires 31.

The mounting 14 for the upper support member 5 is connected by members 34 to guide control rods 35 which are secured to the walls 2 by wires 36 connected to members 37. Bearing rollers 38 are connected to members 34 and rest on a raised track 39.

The members 34 extend downwardly through circular openings 40 in the lower support members. In this case the reciprocating motion is in the direction of the arrows 40 as shown in Figure 2, again the wires 36 acting to restrain movement in directions normal to the reciprocating movement away from the wiring.

Thus, when the motor 7 is operated the relative movement of the upper and lower support members is translated by the guide members provided by the rods into linear movement with the members reciprocating at right angles to each other, the amount of movement being dependent upon the throw of the adjustable cam 8.

In the arrangement shown in Figure 1 the upper support member 5 is not hinged to the carrier 1 4 but is located in position on pins 42, the member 5 resting on the glass sheet 4. A suitable light source 43 is provided above the support members and the base 1 is located in a suitable casing part of the upper portion of which is indicated at 44 in Figure 4. The casing carrying light and speed controls.

The apparatus can be used in well known fashion to provide art work and as the technique of operating this kind of photographic distortion apparatus is well known in itself it will not be further described herein.

It will be appreciated that although an adjustable cam system is described herein there are many other ways of providing the reciprocating linear movement, for example, separate cams or linkages could be provided for each support member on the same or on opposite sides of a bse and linkage system could also be employed. Again, there are also many ways of restraining the support members to provide the linear movement, for example by means of roller guides or rails.

Claims

1. Photographic distortion apparatus including a lower film support member having a substantially flat surface and mounted for reciprocating linear movement in predetermined directions parallel to said flat surface, a transparent upper film support member located above the lower support member and having a substantially flat surfface parallel to the flat surface on the first member and mounted for reciprocating linear movement in predetermined directions parallel to its flat surface and normal to the direction of movement of the first member, means for driving said first and second support members to cause said movement and means for simultaneously varying the stroke of each member.

2. Photographic distortion apparatus as claimed in claim 1 in which the means for varying the stroke acts simultaneously on both support members.

3. Photographic distortion apparatus as claimed in claim 1 or claim 2 In which said drive means acts to tend to Impart an orbital relative movement to the support members which is translated into reciprocating movement of each support member by guide means.

4. Photographic distortion apparatus as claimed in claim 3 in which one support member carries a rotatable cam which acts on the other support member to tend to impart said relative orbital movement.

5. Photographic distortion apparatus as claimed in claim 4 in which the means to vary the stroke of the support members is provided by means for adjusting the throw of the cam.

6. Photographic distortion apparatus as claimed in claim 4 in which said rotatable cam rotates about an axis which is fixed in relation to said lower support member.

7. Photographic distortion apparatus as claimed in any one of the preceding claims including means for causing substantially relative linear movement between the support members in a predetermined direction.

8. Photographic distortion apparatus as claimed in claim 7 when dependent on claim 5 or claim 6 in which the means for causing said relative linear movement between the support members in a predetermined direction is also provided by the means for altering the throw of the cam.

9. Photographic distortion apparatus as claimed in claim 8 including means for locking said cam adjustment means at different throw positions and which when locked causes operation of the drive means to impart said reciprocating movement of the support members. and which when unlocked causes substantially relative linear movement between the support members in a predetermined direction.

10. Photographic distortion apparatus as claimed in claim 9 including manually operated means for causing relative linear movement between the support members in a predetermined direction.

11. Photographic distortion apparatus as claimed in claims 5 to 10 in which said cam adjustment means includes a screw threaded member on which a rotatable adjustment element can act to cause axial movement of the screw threaded member to adjust the throw of the cam.

1 2. Photographic distortion apparatus as claimed in claim 11 when dependent on claims 9 and 10 in which said rotatable adjustment element is provided by a pinion which, when the locking means is unlocked, can be freely rotated by the drive means to cause rotation of the screw threaded member to adjust the throw of the cam.

1 3. Photographic distortion apparatus as claimed in claim 1 2 in which said pinion, when the locking means is locked and the drive means is operated, causes rotation of the cam.

1 4. Photographic distortion apparatus as claimed in claim 1 3 in which said pinion is a bevel gear which is acted upon by a second bevel gear driven by the drive means.

1 5. Photographic distortion apparatus as claimed in claim 14 including a third bevel gear acting on the first bevel gear and which is connected to the locking means and said manually operated means.

16. Photographic distortion apparatus as claimed in claim 1 5 in which said manually operated means comprises a rotatable operating member to which the third bevel gear is connected, and which incorporates locking means for releasably locking it to one of the support members or a part attached thereto.

17. Photographic distortion apparatus as claimed in any one of the preceding claims 10 to 1 6 in which the predetermined direction of the relative linear movement between the support members can be adjusted by rotating said adjustable cam.

1 8. Photographic distortion apparatus substantially as described herein with reference to and as shown in the accompanying drawings.