Abstract: A decorative system for lamp shades and related articles relies upon a plurality of clips having spring tension between their parts. The clips are easily added or removed from a lamp shade or similar article without destroying or otherwise compromising the fabric of the lamp shade. Virtually every style, size and shape of lamp shade can be decorated by the present system.

Abstract: Integrated fold-up reflector mounting brackets to mount a reflector to a lighting fixture or luminaire are fabricated as an integral part of the reflector during the production thereof without the use of additional material, components and operations. The top of the reflector is fabricated with a stamping operation to provide an opening therein to provide for the mounting of a lamp socket and to allow for the flow of ventilation air therethrough. First and second fold-up mounting brackets are stamped and fabricated as an integral part of the top of the reflector. Each of the first and second fold-up brackets comprises a plurality of contoured ribs, with at least one of the contoured ribs having a truncation therein defined along a fold line for the mounting bracket.

Abstract: An attachment ring for clamping a globe having a flanged neck to a lighting fixture. The attachment ring comprises an encircling member which is configured as a "C" in an open condition. The encircling member is L-shaped in cross section, the bottom of the "L" providing a ledge on which the flange of the flanged neck of the globe will come to rest. An actuator constricts the C-shaped encircling member until it is closed, thereby attaining configuration of an "O" in a closed condition. When moving to the closed condition, the encircling member frictionally engages a tubular member of the lighting fixture from the outside of the lighting fixture. Simultaneously, the ledge moves under the flange of the globe, so that the globe is constrained against falling downwardly. The actuator is operated by a manual lever, and includes a locking feature maintaining engagement of the globe.

Abstract: A lighting fixture for filming motion pictures includes a lamp housing having a rear bezel and a front three-sided frame. A rear reflector slidably attaches to the rear of the lamp housing over the bezel. A snoot has a rear bezel slidably fit into the three-sided front frame on the lamp housing. The snoot has a front frame similar or identical to the front frame on the lamp housing, so that a second snoot can be slidably attached onto the first snoot. The frames form slots for receiving and holding gels. The lighting fixture may used as a simple open front reflective lighting fixture, or the snoots or gels may be added to achieve various lighting conditions.

Abstract: A reflector used in a lighting fixture wherein a relatively thin, flexible, reflecting surface is placed against a precisely formed curve in a frame. The reflecting surface is then clamped against the precisely formed curve and adopts the shape of precisely formed curve. A method according to the invention cuts the precisely formed curve from a piece and then uses both parts of the piece to clamp the reflective surface in place. It is preferred that the reflective sheet be placed against and clamped at least at opposite edges.

Abstract: A device for fixing the screen of a ceiling light fixture to the base of the ceiling light fixture, wherein a seat is formed in the peripheral region of the base and is adapted to receive and retain an end of an elastic hook-shaped element, the opposite end whereof is adapted to engage, with a snap action, an undercut formed in the peripheral region of the screen, so as to clamp the rim of the screen against the rim of the base.

Abstract: A lighting fixture includes one or more corner structures for connecting adjacent panels at their adjacent corners or edges at predetermined angles to each other. The corner structures include sockets of which at least one includes a single flange member for adhering support on one side of lighting fixture panels with the other sockets each including at least a single flange member for adhering support on one side of lighting fixture panels. Adjacent ones of the sockets are attached to each other at cantilevered ends or at the bases of the flange limbs, or at combinations thereof. The corner structure can be fabricated from sheet metal by cutting and stamping the corner structure according to a predetermined pattern.

Abstract: The mask has a cap from which two deformable legs protrude. The legs are deformed to permit the outermost parts of the legs to be snapped into a groove in the socket that carries the lamp of the dental light. The mask is not attached to a reflector shield, thereby simplifying the manufacture of the overall lamp.

Abstract: A lighting fixture includes one or more corner structures for connecting adjacent panels at their adjacent real or virtual corners or edges at predetermined angles to each other. The corner structures include sockets of which at least one includes a single flange member for adhering support on one side of lighting fixture panels with the other sockets each including at least a single flange member for adhering support on one side of lighting fixture panels. Adjacent ones of the sockets are attached to each other at cantilevered ends or at the bases of the flange limbs, or at combinations thereof. The corner structure can be fabricated from sheet metal by cutting and stamping the corner structure according to a predetermined pattern.

Abstract: A stretchable chandelier ornament string assembly provides a plurality of elongated spring elements joined by a common runner and formed from a continuous piece of flat spring material stock. The runner is attached to a chandelier frame and each of the spring elements engages a chandelier ornament string. Displacement of the spring elements generates tension in the ornament strings to maintain the ornament strings in substantial predetermined alignment. The spring assembly can be formed into a non-planar orientation by the chandelier frame to generate a variety of shapes and patterns of chandelier string attachment locations.

Abstract: An automotive vehicle headlamp assembly is provided which includes a reflector housing having an open front end, a first reflector surface and a second surface projecting forward from the first reflector surface; a bulb connected to the housing projecting forward from the reflector surface providing a source of illumination; a lens covering the open end of the reflector housing; and a bulb shield having a first portion generally adjacent the bulb, blocking a portion of the illumination given off by the bulb. The bulb shield has a foot connected by a leg to the first portion. The foot has a front end captured between the lens and the reflector housing and a rear end captured in the intersection between the first and second reflector surfaces.

Abstract: A luminaire, such as an indirect linear luminaire, is provided with a floating reflector assembly tied directly to securement points in the luminaire housing. The reflector assembly has a reflector element with tie down openings which overlay the reflector securement points and compliant spring-like retaining clips which overlap the tie down openings and which are secured at their center portion to the underlying securement points by a screw fastener. The width of the retaining clips are narrower than the tie down opening such that the center portion of the retaining clips can be drawn into and contact the housing securement points to provide good electrical grounding. The pressure contact of the retaining clips holds the reflector down yet permits it to float within the housing when the housing is distorted, such as by twisting, thereby avoiding distortion of the reflector.

Abstract: A reflective arrangement for tube type lighting comprises a reflective sheet of a resiliently flexible heat resistant material arranged behind the lighting tube. Longitudinal edges of the reflective sheet along each side of the lighting tube are protected by molding portions. A pair of clips is attached to the lighting tube, one at each end thereof, each clip having a center gripping portion for gripping the lighting tube and extending arm portions at each side of the gripping portions having retainers for securing the edge of the molding portions at each side of the reflective sheet.

Abstract: An existing luminaire may be updated with an improved reflector by removing the lamp from an existing lighting fixture and inserting a lamp socket extender which is designed to accept a plurality of different configuration reflectors for various types of lamps having selected intensities, diffusion and distribution characteristics. The reflector adaptor eliminates adjustment problems involving the position of the reflector relative the lamp.

Abstract: A receptacle for light emitting diodes includes a housing defining an opening at one end and having a bottom at another end; a circuit board from which a plurality of light emitting diodes extend being adapted to be received in substantially a middle inner periphery of the housing; a hole being defined in a periphery of the housing; a ridge being longitudinally formed along an inner periphery of the housing; a stop being formed beside the ridge substantially in a same longitudinal level with respect to the hole; a light-resistant device including a ring frame across which a plurality of louvers are connected, a groove defined at an outer periphery of the ring frame, a snapping member being formed on the outer periphery of the ring frame diametrically opposite to the groove; whereby the light-resistant device is positioned at substantially the opening of the housing, with the groove of the light-resistant device receiving the ridge of the housing and the snapping member of the light-resistant device being reta

Abstract: A light fixture includes a housing having a top wall and a front wall. An upright lip on the housing projects up above the top wall generally adjacent the front wall. Fasteners mount at least one lamp on the housing forward of the front wall. A light diffuser is further provided including a hollow shell having a back with an opening therein to permit entry of the lamp and the housing lip into the shell as the diffuser is installed on the housing. When the diffuser is installed on the housing, the lip extends up on the inside of the shell closely adjacent an interior surface of the shell above the opening. The lip and interior surface of the shell are engagable to hold the diffuser on the housing, without the need for mechanical fasteners, in a position in which the diffuser shell is suspended on the housing with the back of the diffuser shell in close, generally abutting relation with the front wall of the housing.

Abstract: A retaining device held in a compact, lensed, task lighting fixture operates to retain the lens in the fixture and to facilitate the removal of the fixture's fluorescent lamp which is otherwise difficult to access. The retaining device is comprised of a strip of resilient material having a base end mounted in a fixed position within the fixture, a resilient middle strip portion shaped to extend around the base end of the fluorescent lamp, and an outwardly biased distal end extending to contact and retain the lens in the fixture housing.

Abstract: A lamp used in photography and television comprising a housing having a filter cavity into which an optical element provided with a handle can be introduced, the housing having first and second shafts situated between two sidewalls of a holding device and extending in a longitudinal direction of the housing and bridging the filter cavity, the handle of the optical element is provided with first and second recesses which are arranged to engage the first and second shafts, respectively, the first shaft being surrounded by the first recess of the handle to allow the optical element to swing about the first shaft from a working position, in which the optical element is located within the filter cavity, into a second position in which the optical element is removed from the filter cavity and the second recess engages the second shaft, and a locking mechanism is provided for retaining engagement of the second recess with the second shaft when the optical element is in the second position.

Abstract: A hook and ornament assembly for a chandelier is provided. The assembly includes a hook with a first end terminating in a straight end-segment with a free end. A first ornament defining a straight bore is positioned on the end-segment, with the end-segment extending into the bore. The hook also has a first stop portion for limiting advancement of the first ornament further onto the hook and a second stop portion for limiting advancement of the first ornament off of the free end of the end-segment. The hook is constructed and arranged so that the straight end-segment can be spring biased away from the second stop and so that the first ornament can be positioned on and off the end-segment without permanently bending the hook. Hooks for such assemblies and methods for forming such assemblies also are provided.

Abstract: A fluorescent indirect lighting fixture of the hidden source offset reflector type incorporates a novel reflector mounting system which provides advantages of extended uniform "wash" illumination with unusual concealment of the light source from direct view, along with extremenly easy reflector installation and replacement. The reflector, formed to the required special curvature from a thin sheet of suitable metal such as high purity aluminum, is sprung into place between two opposite edges of a window opening in the metal fixture housing in a tongue-and-groove type engagement along the two edges where it is retained in place by the resilience of the reflector with no need for adhesives, screws or other fastenings. Illumination coverage and lamp concealment are both maximized by configuring the reflector and its mounting system uncompromisingly such that both of the straight end regions of the curved reflector extend smoothly and fully to a plane flush with the surrounding ceiling or wall surface.

Abstract: The invention relates to a chandelier including chandelier trimmings connected to a framework by way of a hook and an attachment whereby the attachment is integral with at least part of the framework. The attachment consists of two openings which may be two slots or a slot and a hole which are located in the framework in such a way that the hook can be introduced into the attachment with the minimum of rotational movement and in such a way that the chandelier can be constructed even in close to the ceiling arrangement. It is advantageous if the framework is made from a flat strip or a plate. The hook is formed from wire and consists of a series of bends provided in such a way that when the hook is located in the attachment the trimmings achieve their correct position such that the framework is hidden by the trimmings. In this way, the framework need not be made of an ornamental material.

Abstract: An underwater light source includes a sealed beam arc lamp within a wrought and machined, generally cylindrical aluminum housing. The watertight housing has an enlarged diameter at one end to receive the lamp and tapers to a smaller diameter at the other end, which receives the ignitor for the lamp. The larger end is covered with a heat resistant cover glass, and the smaller end is closed. A cylindrical accessory mounting ring is attached to the front end of the housing, and the ring has ventilation openings therein to release heat generated by the lamp.

Abstract: An optically tinted cover for a headlight of an automobile includes a sheet member for covering the headlight and a device for attaching the sheet member to the automobile.

Abstract: A lamp reflector has a dished body with a lamp-receiving sleeve having an open end. Spring clips hold a lamp so that lugs on a flange of the latter engage against the base of slots in the sleeve. Each clip has a pair of legs which embrace the wall of the sleeve. The inner leg has a hooked end engaging over an internal rib in the sleeve. Each clip also includes an arm having a region which engages against the flange of the lamp to hold the latter in position.

Abstract: A holder for detachably mounting a glass electric lamp dome which includes a pair of dome holding arms mounted to a lever arm which in turn is pivotally mounted on a base plate. The lever arm and the dome holding arms are actuated by a finger engageable lever formed as part of one of the dome holding arms and having a finger engageable terminus at the end opposite the end attached to the pivot arm. A feature is spring biasing means connecting the base plate and the lever arm to continuously urge the dome holding arms outwardly in dome holding locking position unless the finger engageable dome holding arm is moved inwardly. Another feature is lock means associated with said finger engageable dome holding arm to premit the locking of said mechanism in a dome disengaging position so that the dome can be removed and replaced.

Abstract: This illuminated house number enclosure is designed to fit over an existing outside light fixture of a house, for easy identification of the house number at night and in bad weather. Primarily, it consists of a pair of mounting bases secured to shingle portions of a house, and a transparent main body is received on the mounting bases and includes numbers on its face for house identification.

Abstract: The light shield-reflector for a lighting implement comprising a substantially tubular base associated with a reflector element of multiple type constituted by a set of superimposed wings spaced apart from each other. The structure of the wings shows substantially a "U"-shaped plan and a parabolic cross-section. The light flux forms a cone-shaped light and diffuses by passing through the space existing between two adjacent wings.

Abstract: Housing for long-field lamps comprising interchangeable louver insert. A lock in the form of a spring arm that is secured to the face wall of the housing is suitable for the mutually releasable interlocking of the housing and louver insert in housings of long field lamps having an interchangeable louver insert. This lock has its free end projecting beyond the upper, bent-off edge of the end louver lamella when in engagement with this upper edge and being capable of being unlocked by the accessible gripping surface that is thereby formed. When such a louver is to be interchanged for a louver insert having higher louver lamellae, then, due to the upper, bent-off edge of the end louver lamellae now being higher, a refitting of the lock is required by placing it higher on the face wall of the housing.

Abstract: An optically transmissive, substantially cylindrical enclosure surrounds a light source. A generally circular base includes a vertically oriented first flange section dimensioned to fit coaxially within a vertically oriented lower section of the enclosure. The base includes a horizontally oriented, second flange section coupled to the first flange section and oriented perpendicular to the longitudinal axis of the lightining fixture. A circular clamp compresses a resilient gasket between a lower, horizontally oriented surface of the enclosure and the horizontally oriented second flange section of the base to create an hermetic seal between the base and the light fixture enclosure.

Abstract: To permit use of materials having different melting temperatures and still rovide a two-component base for a lamp operating at high temperature, for example a halogen incandescent lamp, the base includes a base cup (5) of high heat-resistant plastic material, connected to an attachment element (13) by interengaging snap-in spring fingers (15) and recesses (9,10). To prevent separation of the attachment element from the base cup, the spring fingers are located inside of a solid wall portion of the attachment element and the base cup is formed with projections (8, 11) for example a circumferential flange or bead, extending over the spring fingers when they are snapped into matching recesses formed in the base cup so that, after assembly, the connection cannot be loosened, either inadvertently or deliberately.

Abstract: An arrangement for fastening a glass in a bulkhead lighting fitting, wherein three small columns are fixed with and project perpendicularly from the bulkhead fitting and are arranged substantially at the apices of an equilateral triangle. The small columns each include a sidewardly opening groove to accommodate an edge of the removable glass. One of the small columns has a rotary head movable between open and closed positions, the head when in the open position permitting the glass to be moved downwardly into the groove, whereupon rotation of the head into the closed position results in the edge of the glass being confined within the groove.

Abstract: An assembly for supporting a glass globe having a recessed neck portion the globe is retained within a receptacle or holder by a separate arcuate band of metal which is compressed and resiliently retained within the receptacle and has formed on surface portions of its perimeter a pair of spaced extrusions or nibs which fit within the recess of the globe neck. The band is additionally provided with a threaded bushing for receipt of a screw which when seated in the bushing holds the band in position within the holder and provides, with the nibs, a three-point suspension for the globe.

Abstract: An improved portable fluorescent light unit is disclosed in which the improvement comprises a pair of electrically insulated lamp supports which facilitate assembly of the unit. Each lamp support may comprise an inner socket element and an outer supporting element. The inner socket elements fit against the ends of the lamp, and each socket element has a pair of apertures in which electrical connectors are mounted. The outer supporting element is attached to the housing of the unit and has a central opening into which the inner socket element is inserted. The lamp supports may also include means for accommodating thermal expansion of the housing by having the inner socket element being slidably mounted with the opening and movable in a direction parallel to the axis of the fluorescent lamp.

Abstract: A series of resilient blades are circumferentially disposed on an annular member to which a light fixture is attached and are adapted, through a rotational sliding motion, to come in overlapping interengagement with a second series of resilient blades disposed circumferentially on a base member mounted to the structure supporting the light fixture.

Abstract: Devices and methods are disclosed which provide for the indirect, substantially glare-free, directional lighting of three-dimensional objects, by which artificial light is generated at a central point which is recessed in close proximity to the object to be illuminated. Said light enters light-conductive means through an optical interface and is conducted towards and projected in the direction of such object in the shape of a predetermined light beam or mantle substantially enveloping or highlighting selected surfaces of the object without significant scattering of light. Shielding means protect the eyes of observers from direct view of the light source. The arrangement of components permits multi-directional, centripetal, substantially glare-free viewing by a plurality of observers grouped around the illuminated object.

Abstract: A fiber-optic light system is disclosed for providing highly concentrated, cool light to projectors and reproducer sound heads, such as the type found in the projection room of a movie theater. The light beams onto a film to project the film's images onto a screen and release its soundtrack. In the preferred embodiment, a system is disclosed for providing fiber-optic light to a plurality of projector-and-reproducer sound sets from a single light source. A plurality of fiber-optic cables are connected to a standard xenon lamphouse, wherein each of the cables has a bifurcated "free" end with two trunks. One trunk removably connects to the projector by a coupling block that easily fits onto a mount attached to the projector's casing, while the other trunk connects to the reproducer sound head by a similar block and mount.

Abstract: A lamp stand adapted to support in a fully expanded state a collapsible oriental lantern formed by an open-ended translucent shell on a floor or table surface. The upper opening of the shell is bounded by a top rib to which is attached a spider whose center hub has a hole therein, the lower opening being bounded by a bottom rib provided with tie strings or other leg connectors. The stand includes a raised mounting plate supporting a lamp socket and a harp from which upwardly extends a vertical rod that passes through the hole in the spider hub. The rod has an elastic collar thereon which is axially shiftable to a point under the hub to maintain the upper end of the lantern at this level, which print depends on the length of the lantern. Depending from the mounting plate is an array of legs each having an outwardly sloped upper section and a straight lower section whose foot rests on the surface.

Abstract: A diffusion device for a flash gun is provided in the form of a translucent box-like structure which fits on the end of a commercial flash gun. In accordance with one embodiment of the invention, opaque shields are provided for the front and back of the diffusion device which can be selectively added or removed to produce special effects. In accordance with another aspect of the invention, a slot is provided in the top of the diffusion device for retaining a reflector.

Abstract: A lighting device of the free-standing type, capable of diffusing beams of light rays propagating through and emitting from the optical wave guides. A reflecting member is placed opposite the exit end of the optical wave guides to diffusingly reflect and diverge the light rays issuing from the optical wave guides thereby to light up a wide area with soft light rays.

Abstract: A reflector assembly for replacing a fluorescent lamp from a multi-lamp fixture having a top wall and oppositely disposed end and side walls enclosed by a diffuser plate. The assembly includes a reflector member extending longitudinally between the end walls of the fixture and width wise between the top and side walls of a fixture. The reflector member includes a plurality of walls disposed at obtuse angles with respect to one another to reflect a substantial portion of the illumination received from a remaining source lamp to produce a lamp image under the center line of the removed lamp on the diffuser plate so that it appears that a complete number of lamps are provided in the fixture even though less than a complete number of lamps are employed.

Abstract: An object illuminating apparatus for the display of art objects and the like. The apparatus directs a remote light source through a common grouping of optical fibers, and the like, to the proximity of the object being displayed. The initial grouping of fibers is further divided into smaller separate light directing arrays which are held within clear acrylic plastic tubes. Such tubes are heated and then selectively directed at various angles to cover the various surfaces of the object being displayed.

Abstract: A variable magnification "zoom" spotlight assembly is disclosed in which the diameter and focal length of the focusing lens and object lens are selected so that the angle of incidence of a light ray as it emanates from the lamp and reflector of the assembly and thereafter from the focusing and objective lenses decreases by a constant factor. This angular relationship is established by selecting the diameter and focal length of the focusing lens and objective lens and the diameter and length of the reflector according to the following angular relationship:B.sub.R /B.sub.F .congruent.B.sub.1 /B.sub.R .congruent.B.sub.2 /B.sub.1 =kWhere:B.sub.F =angle of the filament to reflector as measured from the focal axis;B.sub.R =angle of gate to reflector as measured from the focal axis;B.sub.1 =angle of focusing lens as measured from its focal length along the focal axis to its radius;B.sub.2 =angle of objective lens as measured from its focal length along the focal axis to its radius; and,k=constant.

Abstract: A recessed lighting fixture used in association with a suspended ceiling system made up of several spaced grid members. The lighting fixture is comprised of a fixture housing having means for supporting at least one fluorescent lamp and includes a relatively thin deflectable top plate which in turn may include a reflecting surface disposed over the fluorescent lamp. Means are provided for securing the fixture housing to the grid members. The louver assembly of the fixture is mounted in a simplified manner and includes a top portion designed to contact the deflectable top plate during insertion and a bottom portion including longitudinally extending sides designed to rest upon and be supported by the spaced grid members. The louver's bottom portions are insertable on the grid members in sequence, first one and then the other, whereby the louver assembly is firmly supported in the fixture housing without the requirement of additional hardware such as springs, latches or the like.

Abstract: A "wall wash" assembly for use with a ceiling mounted, recessed lighting fixture comprising a reflector housing having an open end, includes a ring member dimensioned for receipt in the open end of the reflector housing. A concentric ring segment is mounted on the ring member for movement 360.degree. thereabout. An auxiliary reflector is mounted on the ring segment for movement therewith. Positioning of the auxiliary reflector by movement of the ring segment with respect to the ring member provides a desired "wall wash" illumination pattern. An optional baffle member is receivable on the ring member opposite the auxiliary reflector for blocking light emanating from the reflector housing to be excluded in the "wall wash" illumination pattern.

Abstract: A light reflector unit (12) for use with a photographic camera (10) for reflecting light from a light source (13), such as a flash gun, towards the subject to be photographed, the unit (12) comprising a hollow casing (15) having a window (16) for admitting light from the light source (13) into the casing (15), means (28) within the casing 15 for splitting the admitted light and for condensing the split light into separate beams of light, reflective surfaces (26) within the casing (15) for deflecting each beam of light to one of a plurality of windows (18) located such that when the reflector unit (12) is positioned on a camera (10) they face in the same direction as the lens of the lens unit (11) of the camera (10) and are disposed at discrete locations around the lens unit (11).

Abstract: For the mounting of a lamp which is firmly connected with a reflector, at least two coil springs are so arranged parallel to an attachment part that they contact the reflector on its outer side close to the outer periphery. The reflector is so developed at these points of contact that components of force perpendicular to the attachment surface are produced by the springs.

Abstract: A projection lighting unit which enables dual insertion of the unit's glass reflector therein. The reflector, having a tungsten-halogen projection lamp sealed therein, can be inserted in a vertical manner (and therefore parallel to the plane of the unit's faceplate) or it can be inserted horizontally (or perpendicular to the planar faceplate). The means of grasping and retaining the reflector within the unit's lampholder assembly preferably comprises a steel wireform having two deflectable segments (or elements) which deflect outwardly when engaged by the reflector. Removal of the reflector is possible in similar but reverse fashion.

Abstract: A clamp for a flash gun is provided which can be slipped on and off the gun and which has a slot therein whereby a bounce-flash reflector can be retained in said slot. In accordance with one embodiment of the invention, a second, opposed slot is provided so that one slot is adapted to retain a reflector and the opposite slot is adapted to retain a diffuser.

Abstract: Light mounting tapes receiving electric light sockets of the type commonly used for Christmas decorations are provided in elastic form so that they may be stretched as desired between mounting fasteners, as for example around a door or window frame. The tapes provide a plurality of receptacles along their lengths. The tapes can be furnished in segmented lengths and easily secured together in series to provide a desired overall length. The elastic properties of the tapes facilitate stretching them into taut condition for fixedly positioning the electric lights mounted in the receptacles thereof.

Abstract: A portable lighting system which includes a stand having an adjustable effective length which positions lights carried on a frame at a predetermined vertical position with respect to a supporting surface. The frame is releasably secured to the stand and can readily be set up and dismantled for transport in a compact space. Lights carried by the frame include a new and simple technique for attaching the gelatine filter holders, and may be connected to a foot operated control box which includes switches actuated to energize preselected lights or groups of lights. The energized lights or preselected energized lights can be intensity modulated with a foot operated dimmer while leaving the operator's hands free to play a musical instrument.