Abstract: Filter system operates to provide reasonable seeability for human visual system while simultaneously limiting the total radiation energy impinging upon the eye. System comprises a transparent substrate which carries a plurality of thin layers having indices of refraction which alternately vary from a high index to a low index. Radiations passing the filter system are substantially confined to three bands centered at about 450 nm, 530 nm, and 610 nm with the width of the bands being from about 3 nm to about 50 nm as measured at one-half the maximum measured radiation transmission of each of the bands.

Abstract: Colored object which is to be illuminated by many different types of sources of illumination and which exhibits an improved constancy of color appearance upon change of illuminants. The radiation-absorbing exterior portion of the object has color-absorbing components which combine to exhibit reflectance bands peaking at about 450 nm in the blue-violet, about 530 nm in the green and about 610 nm in the orange-red. The reflectance bands are substantially confined to a radiation range of 50 nm to 60 nm as measured at one-half of the maximum measured reflectance of the bands. This range can be expanded to 40 nm to 80 nm with some sacrifice in performance. The relative proportions of each of the color-absorbing components are preselected to produce a desired composite color for the exterior portion of the object. There is also provided a method for making the exterior portion of the object.

Abstract: Method and apparatus for rapidly measuring any of a large number of characteristics of lamplight. Apparatus extracts from the illumination being measured seven narrow visible bands and one wider band of ultraviolet. The measured power in each of the visible bands is multiplied by a weighting coefficient and the combination of the products provides a number which is indicative of the lamplight characteristic being measured. The measured power in the ultraviolet band is separately weighted from the measurements in the visible bands.

Abstract: High-intensity-discharge lamp of the mercury-metal halide type efficiently illuminates objects with excellent color appearance. The arc tube filling comprises the usual inert, ionizable starting gas and mercury in predetermined amount as required to provide a predetermined operating voltage drop between the lamp electrodes. The metal halide filling substantially comprises a predetermined limited amount of thallous iodide, a predetermined limited amount of stannous iodide and a predetermined limited amount of calcium iodide. The stannous iodide is used in such amount that it serves primarily to enhance the emission of the calcium iodiode and the amount of stannous iodide is sufficiently limited to curtail the generation of the characteristic continuous tin emission. The calcium iodide is present in greater gram amount than the tin iodide so that the effects of the calcium iodide emission are predominant.

Abstract: High-intensity-discharge lamp is fabricated in a fashion generally similar to a standard high-pressure-mercury lamp which has a red-emitting phosphor coated on the outer envelope. In the present lamp, the discharge-sustaining filling in the arc tube is modified to include a small, predetermined proportion of cadmium which adds radiations of a wavelength of about 490 nm to the composite lamp emission. The resulting composite emission has greatly improved color-rendering properties as compared to a similar lamp which does not incorporate the cadmium addition to the arc tube filling.

Abstract: Method and apparatus for expressing as a number the relative brightness of artificial illumination as it is perceived by the average observer. There is extracted (i.e., detected) from the illumination to be measured, a blue-appearing narrow band, a green-appearing narrow band, a yellow-appearing narrow band and a red-orange-appearing narrow band. From these extracted bands are generated six different signals: a signal expressed as (aB) where (a) is about 0.23 and (B) is the watts of energy in the blue band, a signal expressed as (bG) where (b) is about 0.97 and (G) is the watts of energy in the green band, a signal expressed as (cR) where (c) is about 0.33 and (R) is the watts of energy in the red-orange band, a signal expressed as (dY) where (d) is about 0.19 and (Y) is the watts of energy in the yellow band, a signal expressed as (eG) where (e) is about 0.25 and (G) is the watts of energy in the green band, and a signal expressed as (fR) where (f) is about 0.

Abstract: Method and device for efficiently generating white light with good color rendition of illuminated objects. This is achieved by blending three different colors of light, namely, a green to yellow-green color of light, an orange to red color of light, and a purplish-blue to greenish-blue color of light. The relative intensities of the blended colors of light are selected to produce white light of predetermined ICI coordinates. The resulting blended light has at most only a limited amount of radiations of a wavelength shorter than 430 nm and at most only a limited amount of radiations of a wavelength longer than 630 nm. Also, the blended light has at most only a limited amount of radiations of a wavelength of about 575 nm and at most only a limited amount of radiations of a wavelength of about 500 nm.

Abstract: Method and device for efficiently generating white light with good color rendition of illuminated objects. This is achieved by blending three different colors of light, namely, a green to yellow-green color of light, an orange to red color of light, and a purplish-blue to greenish-blue color of light. The relative intensities of the blended colors of light are selected to produce white light of predetermined ICI coordinates. The resulting blended light has at most only a limited amount of radiations of a wavelength shorter than 430 nm and at most only a limited amount of radiations of a wavelength longer than 630 nm. Also, the blended light has at most only a limited amount of radiations of a wavelength of about 575 nm and at most only a limited amount of radiations of a wavelength of about 500 nm.

Abstract: A device to generate light of a quality which will accent the mismatch in color appearance of objects having different spectral reflectance curves but which appear at least generally similar in color and lightness under illumination by daylight. As there are many objects which match under one illuminant such as daylight, but do not match under other illuminants, there are many applications in which it is desirable to provide for early detection of potential mismatches. This invention generates visible radiation substantially confined to at least two of the 405-435 nm, 475-505 nm, 565-595 nm, and 645-675 nm wavelength ranges, and which preferably has less than 20 percent of the radiations in the 435-465 nm, 525-555 nm and 595-625 nm wavelength ranges.