GB2281130A - Illuminating subjects for cinematography and photography - Google Patents

Description

2281130 1 ILLUMINATING SUBJECTS FOR CINEMATOGRAPHY AND THE LIKE The

invention relates to the field of lighting effects f or use in illuminating photographic and cinematographic subjects or the like. In particular, the invention relates to the provision of arbitrary patterns of light and/or shadow by means of a masking and/or filtering arrangement placed in front of a light source.

Specific shaped patterns of light and shadow and similar effects are frequently required in the lighting of photographic and cinematographic scenes (see Fig. 1). other applications in theatre, exhibitions, and so on will be apparent. A discussion of current techniques in this field can be found in various books, for example "Lighting for Action" by John Hart (Pub. Watson-Guptill, NY) and in "The American Cinematographer". To define each lighting effect traditionally has required a lot of time and effort on the part of lighting technicians, carpenters and so on, and the techniques used have not afforded much flexibility in practice. Any change in the lighting pattern has tradionally involved a lengthy period of waiting for a new shadow filter to be built and/or re-positioned, while such idle time in the production schedule can prove very expensive.

2 In particular, even relatively simple shadow patterns have traditionally required the construction of special sheets of wood with appropriate outlines and cut-outs, with stands to position them. Simpler patterns have been achieved using a collection of two or three basic wooden shapes (known in the art as "flags" or "slats"), mounted individually on stands and carefully positioned with respect to the scene, the light source and each other, to achieve the desired composite effect.

Any of these processes is known to be very time consuming and therefore expensive, particularly if changes are required once shooting has begun.

The invention provides a system comprising a collection of elementary masking shapes and a single frame or other means by which a selection of said shapes can be supported in the path of a light beam. This system can allow a desired composite shadow shape to be composed freely, without the need to support each elementary shape individually, or to create a special ly-shaped element from wood or the like. At the same time, the shadow of the supporting means is not itself visible.

In some particular embodiments of the invention, shapes of opaque magnetic material are supported in any desired orientation and combination on a transparent but magnetic z 3 screen, placed in f ront of the light source. Such a system can be set up very quickly and re-configured again and again as desired, saving time and money in the production schedule and reducing the need for compromise.

Other aspects and embodiments of the invention feature a frame with magnetic or other fixing material surrounding the light beam, whereby metal or other shapes can be positioned across the light beam, and/or transparent film with pre-printed shadow shapes can be mounted. The frame may also hold coloured or neutral density filter gels, as desired.

Where a magnetic or ferromagnetic, transparent screen is provided, this may be done for example by means of a fine steel mesh. The steel mesh may be freely suspended by being held taut across a frame, and/or may be bonded to a transparent plastic or glass sheet. Of course other, non-magnetic means of adhesion may be employed, including hooks, suckers and self-adhesive elements (including vacuum or friction adhesion between suitably selected plastic materials), as an alternative or in addition to the magnetic adhesion mentioned above. Hook and loop fabric (for example Velcro (TM)) may also be of use, particularly around the periphery or frame of the apparatus.

4 Where pre-printed and/or coloured flexible sheets are included in the system, a quiver, rack or similar receptacle may be provided, either freely standing or attached to part of the system, so that a selection of such sheets are immediately to hand, while being stored and protected for transportation.

The invention also provides methods of making still and motion picture recordings employing the above system, and to still or motion picture recordings wherein subjects have been lit by use of the system.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings.

Fig. 1 shows a film set with a specific shape of lighting effect screen in use.

Fig. 2 shows an embodiment of the invention suitable for use on the film set of Fig. 1.

Fig. 3 shows a cross-sectional view along the line A-A' in Fig. 2.

Fig. 4 shows a system of parts forming an embodiment of the invention.

Fig. 5 is a magnified view of a part of a magnetic screen device suitable for implementing the systems of Figs. 2 and 4.

Fig. 6 shows a cross-sectional view along the line B-B' in one embodiment of the device of Fig. 5.

Fig. 7 shows a cross-section of the device of Fig. 5 according to an alternative embodiment.

Figs. 8 to 12 show various modifications of embodiments of the invention.

Fig. 13 illustrates a flexible pre-printed filter sheet 15 for use with embodiments of the invention.

Fig. 14 shows a quiver suitable for holding various preprinted sheets of the type shown in Fig. 13.

Fig. 15 shows a selection of pre-printed filter patterns.

Fig. 16 illustrates an alternative class of embodiment, in which a desired lighting pattern is created by reflection.

The film set of Fig. 1 features flat pieces of scenery 10, 12, 14 and so on, representing the walls of a room 6 where action is to take place. room.

A camera 16 views the A bright light source 18 upon a stand 20 illuminates one wall 10 of the room in order to create a special lighting effect. Specifically, it is desired to cast patches of light at positions 22 to 28 on the wall, to simulate sunlight shining through a window somewhere outside the field of view of the camera 16. To this end, a specifically shaped filter, mask or "flag" 30 has been constructed and placed on the stand 32 in front of the light source 18. The light source 18 is provided in a conventional manner with flaps 34 etc which can be adjusted to direct the light through the filter 30.

In conventional practice, it is known that the construction of the specific shaped flag 30 will employ electricians and carpenters to specify and create the required cut-outs 36 etc in a piece of board 38, and to mount this on a stand in a suitable position and orientation. It is also common practice, where simpler shadow shapes are required, to use single pieces of wood or whatever held up on adjustable stands in front of the light 18, but the known stands are unwieldy and can be difficult to adjust.

As shown in Figs. 2 and 3, a system to be described 7 herein allows for the construction of simple or complex shadow shapes f rom simple elements, without the need f or individual stands f or these elements and/or the need for specific carpentry operations. The flexibility and time saving achieved can be very significant, particularly when one considers that time wasted on a f ilm set can often cost tens or hundreds of thousands of pounds per day.

The device of Figs. 2 and 3 comprises a frame 50 and a screen 52 which is substantially transparent, in the sense that it casts no visible shadow of itself at the relevant distance. The screen 52 on the other hand does provide a support for various rectangular pieces of opaque material 54 to 64, which can be arranged on the sheet and frame in any desired position. From this it can be seen that the desired window shape comprising four rectangular apertures can be constructed as shown in Fig. 2 very quickly, and can be adjusted (66, 68) in any dimension according to the will of the cinematographer.

Fig. 3 shows a device in cross-section along the line marked A-A' in Fig. 2. It should be appreciated that the drawing is not to scale, so that, for example, the thickness of the transparent screen 52 and the various elements 56, 58, 60 and 64 have been exaggerated for clarity. Arrows 701 and 721 show light passing through 8 the apertures 70 and 72 (see Fig. 2) respectively. On the other hand, arrows 561, 581 and 601 show light which is blocked by the opacity of the elements 56, 58 and 60 respectively.

In one class of embodiments, the elements 54 to 64 are made of flexible magnetic sheet, such as is widely available (for example under trade name FLEXOR from Magnet Applications Ltd., Herfordshire, United Kingdom), while a fine mesh of ferromagnetic metal (not shown in Fig. 3) is bonded to the surface of the transparent sheet 52. The element 64, seen at a distance in the crosssectional view, can be seen to flex sufficiently that it adheres to the screen 52 in between the other elements 56, 58 and 60, while riding up over those elements when need be. Again it should be noted that the thicknesses of various sheets and elements are not represented to scale, being greatly exaggerated in Fig. 3. Both the screen 52 and the magnetic elements are made able to withstand the high temperatures (for example up to 1100C) that can arise in front of a powerful light source.

Fig. 4 shows a particular embodiment of the invention. A large frame and sheet 80 has a width of 1m and a length of 1.33m and has a standard knuckle clamp or similar attachment 81 for a stand. A smaller sheet 82 has a dimension of 0. 5m x 0. 6m, and another standard attachment 1 9 83 is provided. Magnetic elements 84 to 90 are provided in various types and sizes, but in this example each has the form of a rectangle hinged at two places 85 across its width, so that it can be folded into thinner rectangles.

For example, the element 84 comprises opaque magnetic plastic sheet of lm long by 0.3m wide. The sheet may be for example between 1 and Smm thick, depending on desired properties. The tape hinges 85 divide the sheet 84 into three 0.1m strips. This allows an element of lm by 0.1m, lm by 0. 2m, or lm by 0. 3m to be deployed according to requirements, very quickly and simply. Similarly, the element 86 comprises three tape-hinged slats of 0.05m by 0.66m.

The elements 88 and 90 are dimensionally the same as the elements 84 and 86 respectively, but are formed of material which is not completely opaque, but rather provides 0.6 neutral density (ND) filtering. Of course other dimensions and other shapes of elements are often going to be desirable, and a large kit of elements of various geometrical shapes can easily be provided using known materials. The neutral density sheeting is not in itself magnetic, but has metal bound edges, whereby it can be fastened to the magnetic frame.

Fig. 5 illustrates the construction of the transparent magnetic screen 52 in more detail. Quite simply, this comprises a steel mesh 100 with diamond shaped apertures 102 allowing the light to pass through. The thickness of the wires of the mesh 100 has been exaggerated in the drawing, while in practice, 90% or more of the total screen area is within the apertures 102 etc. An opaque magnetic element 104 is attached by its magnetism to the metal screen 100, so as to define a triangular element of the desired shadow.

When a shadow is cast to any significant distance, the shadow of the mesh 100 is not visible, so that the triangular element casts a shadow in isolation, without visible means of support. A number of arbitrarily shaped elements can be attached to the sheet 52.

Fig. 6 shows the detail of Fig. 5 in cross-section, along the crosssectional line B-Bl. A transparent glass or plastic sheet 106 is provided as a substrate, to which the ferromagnetic mesh 100 has been bonded. In Fig. 7, on the other hand, the mesh is suspended without a transparent metal sheet. This has the advantage that wind can pass through the mesh and reduce the windage of the device as a whole, while by choosing suitable mesh dimensions and material, sufficient rigidity can be assured nonetheless. For example, for a mesh 100 11 stretched over a rectangular wooden frame (not shown in Figs. 5 or 7) r it has been found that a suitable material is 19 gauge (lmm) twil weld mild steel wire mesh with a pitch of between one and several centimetres. The wires of mesh may be round in cross-section, but f lattened f aces as shown in the drawings provide better adhesiion. Alternatively, the mesh may be made by stamping out of a flat sheet. Elements can also be hooked or clipped onto the mesh, where magnetic adhesion is not feasible or desired.

Figs. 8 to 12 show further modifications and embodiments, which can be used in various permutations. Reference numerals used in these drawings are broadly the same as those used for corresponding features in the embodiments described above. In Fig. 8, for example, a transparent screen 52 is provided within a frame 50, and magnetic shaped elements can be attached anywhere on this sheet as desired. In addition, however, magnetic strips 110 and 112 are mounted around the front and rear faces of the frame, to allow the mounting of heavier metal shaped elements, and/or flexible plastic transparencies with pre-printed shadow patterns. The drawing shows one such transparency 114 held against the sheet by placing small ferromagnetic pieces 116 etc where they will be held by the magnetic strip 110 inset into the front of the frame 50.

12 In Fig. 9, the screen 52 (including mesh 100) are omitted, leaving only a frame 50 with magnetic strip 110. The flexible sheet and other metal shapes can be placed in arbitrary orientations as with the embodiment of Fig.

8, subject only to the requirement that they should meet the frame. Thus the pattern illustrated in Fig. 2 is perfectly feasible, while it would not be possible to mount a shape in isolation in the middle of the screen area, as was possible with the triangular shape 104 in Fig. 5.

Fig. 10 shows an alternative embodiment in which shape elements can be mounted in isolation from the frame. Here a transparent sheet 120 is attached to a frame 122.

without necessarily having any magnetic properties. A set of opaque shaped elements such as the one illustrated at 124 are provided, each one having one or more suckers 126 on its rear side for attaching it adjustably to the sheet 120.

Fig. 11 shows an embodiment also including a plastic sheet 130 which is transparent and also is sufficiently stiff not to require a frame. Arbitrary shaped elements 132 and 134 can be attached to the screen 130. ThiE shape elements 132 and 134 may be attached magnetically, by suction, or by any form of adhesion desired. For some applications, it may even be tolerable that the adhesive 13 is not removable, so that the elements 132 and 134 cannot be repositioned. Both permanent and self-adhesive materials are widely available which may be used for thir? purpose, including materials with suction or friction (electrostatic) adhesion. At the same time, it is not necessary that all of the shaped elements employed are completely opaque. For example in Fig. 11, shaped element 132 is opaque, while shaped element 134 is partially transparent, being formed either from a neutral density filter material, or from a coloured filter material.

Fig. 12 shows a modification of the frame 50 of various embodiments described above, such that channels or grooves 136 are provided along opposite inwardly facing sides of the frame. This permits rigid or semi-rigid sheets of filter material to be slipped into place, in addition to any shapes which are mounted on the face of the device. The grooves may be useful, for example, for receiving a coloured gel to give overall colour to the light pattern, or a neutral density gel to darken the pattern slightly. A plastic or glass sheet may also be inserted and painted by hand or spray can, if desired. Other filters of interest may include diffusers made of netting ("scrims"), fresnel lenses and the like.

On the other hand, such grooves may also be provided for 14 removing and replacing the magnetic screen 52 itself into a frame. Thus, for example the device of the type shown in Fig. 8 can be transformed quickly into a device of the open-frame type, shown in Fig. 9.

Another type of embodiment is possible, for example, in which shaped elements are held not against the front surface of the device, but rather are sandwiched between two parts of the frame, for example by spring pressure.

There may even be provided a sandwich of two transparent sheets held together in some manner, such that shaped pieces can be suspended in the middle of the aperture without being supported directly by the frame.

In embodiments of this type in which it is necessary to separate the two sheets or two frame pieces to reposition shape elements, it may be necessary to de-mount the device and lay it in a horizontal position, open the two parts of the frame, adjust the shaped elements, and finally re-close the frame pieces, before re-mounting the assembly in its vertical position. Disadvantages are evident in such an embodiment, but other advantages may be found, for example in cheapness of materials, such that the relative inconvenience might be tolerated.

Figs. 13, 14 and 15 illustrate the provision of a number of flexible, preprinted sheets which can be used to provide specific complex shadow patterns. In Fig. 13, a flexible sheet 138 is transparent except for an opaque pattern 140 printed upon it. The transparent sheet can be employed as the sheet 114 in the embodiments of Figs.

8 and 9. For greater convenience, the transparency 138 is provided with metal or magnetic strips 142 and 144, to avoid the need f or separate pieces of metal or magnets (116 in Figs. 8 and 9). Alternatively, hook-and-loop fabric (Velcro (TX)) can be used in place of the strips 142 and 144, with complementary fabric mounted around the frame 50.

Fig. 14 shows a quiver f or holding a number of such transparent sheets in a convenient and accessible manner.

is In particular, the quiver body 146 houses a number of separate tubes for rolled-up sheets, including for example an empty tube 148, and a tube 150 which is housing a rolled-up pre-pri nted transparency.

Conveniently, such a quiver may be built into or attached to the stand which holds up the magnetic screen device.

For this purpose, the quiver 146 is constructed in two halves 146A and 146B, and a hole 152 down the centre of the quiver is adapted to surround the upright leg of the stand of the screen device (32 in Fig. 1). The back edge 154 of the quiver is provided with a cloth hinge or similar, joining the two halves 146A and 146B, while 16 Velcro (TM) or other fasteners 156 and 158 are provided at the front edge. Undoing these fasteners 156 and 158 permits the halves to hinge apart, as indicated by the arrow 160, so that the whole quiver can be mounted and de-mounted on the stand. It is often a problem on the f ilm set that a light source is located at a remote position. By this means, it can be assured that a full range of gels, transparencies and the like are always to hand.

Fig. 15 shows a selection of patterns of opaque printing on transparent sheets, which can be available on the film set and deployed upon the screen at very short notice. The same set of patterns can be provided in coloured or neutral density filtering forms, to provide softer or coloured shadows.

Fig. 16 illustrates the principle of yet another class of embodiments, in which, rather than a transparent screen, the desired shadow shape is imposed upon a mirrored reflector. Positioning such a device may not be so simple as for the transmissive mask embodiments, but avoids the need to provide a transparent and yet magnetic substrate on which the shapes are to be mounted. Silvered plastic film having a mirror-like surface is readily available, and this can simply be placed over a ferromagnetic sheet or mesh in order to receive desired 17 shaped elements such as the rectangles 54 to 64 shown in Fig. 2.

On the other hand, a transparent mounting device as described in the earlier embodiments can be more versatile, in that it can be converted to a reflective type of device simply by the addition of a mirror sheet.

Such a sheet may be provided as one of the flexible transparencies (138, Fig. 13) or may be provided as a sheet for sliding into grooves provided in a frame of the device (136, Fig. 12). When used in transmissive mode, the subject and light source will be on opposite sides of the masking device, as shown in Fig. 1. On the other hand, when a reflective type mask is employed, the light source and subject will both be located on the same side of the reflective masking device, as shown in Fig. 16.

Those skilled in the art will readily appreciate the great improvement in speed, flexibility and convenience afforded by the devices described, and will readily conceive of other modifications and embodiments within the scope of the invention.

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Claims (17)

CLAIMS:

1. A method of illuminating a subject f or photography, cinematography or the like, to incorporate a desired pattern of light or shadow, the method comprising: creating a mask having a shape and position specific to the desired shadow pattern; and. illuminating the subject by means of a light source directed at the mask, wherein the mask is created by arranging a plurality of generic shaped elements on a unitary support, the support being constructed and positioned such that the support itself casts no significant shadow.

2. A method according to claim 1, comprising the further step of repositioning said elements on the support, to modify the pattern.

3. A device for use in illuminating a subject for photography, cinematography or the like, to incorporate a desired pattern of light and shadow, the device comprising a unitary support for a plurality of generic shaped elements in a light beam, such that the support itself casts no significant shadow.

4. A device according to claim 3, wherein the support transmits the light beam.

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5. A device according to claim 3, wherein the support reflects the light beam on to the subject.

6. A device according to claim 3, 4 or 5, wherein the 5 support comprises magnetic or ferromagnetic material.

7. A device according to any of claims 3 to 6, wherein the support comprises an open frame.

8. An apparatus according to any of claims 3 to 7, wherein the support comprises a substantially transparent screen of supporting material.

9. A device according to claim 8, wherein said screen comprises or incorporates a mesh of f erromagnetic metal.

10. An apparatus for use in illuminating subjects for photography, cinematography or the like, to incorporate a desired pattern of light and shadow, the apparatus comprising a device in accordance with any of claims J to 9 and a plurality of generic shaped elements suitable for mounting on the support of the device.

11. An apparatus according to claim 10, further including one or more pre-printed flexible sheets.

12. An apparatus according to claim 10 or 11, wherein said elements are adapted to be held against the support by means of magnetism.

13. A method of illuminating a subject for photography, cinematography or the like to incorporate a desired pattern of light and shadow, the method comprising creating a mask having a shape and position specific to the desired pattern by using a device or apparatus according to any of claims 3 to 12; and illuminating the 10 subject by means of a lightsource directed at said mask,

14. A method according to claim 13, further comprising the step of re- positioning generic shaped elements on the support of the device or apparatus to modify the pattern.

is

15. A picture or motion picture recording wherein a subject has been illuminated by a method according to claim 1, 2, 13 or 14.

16. A method of illuminating a subject for photography or cinematography, substantially as described herein with reference to the accompanying drawings.

17. An apparatus for use in illuminating a subject for cinematography, photography or the like, substantially as described herein with reference to any of the accompanying drawings.

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