XXVII.—A Colour-Vision Spectrometer

1926 ◽  
Vol 45 (3) ◽  
pp. 302-307
Author(s):  
W. Peddie
Keyword(s):  
Blue Light ◽  
Focal Plane ◽  
Colour Vision ◽  
Wave Length ◽  
Established Fact ◽  
Average Wave ◽  
Collimating Lens

It is now a thoroughly well-established fact that a satisfactory match to any coloured light observable in nature can be made by a combination, in suitable proportions, of three standard lights suitably chosen from a spectrum. It is customary to choose for the standards a red, a green, and a blue light of definite average wave-length in each case. The greatest deviation from the average is made so slight that there is no visible difference in colour between the extreme components present in any one standard. A simple way (used by Maxwell) of obtaining these standards would be by means of an ordinary spectroscopic arrangement in which light is focussed on a slit, and is parallelised by a collimating lens, after which it passes through a prism and the object glass of a telescope, on whose focal plane a spectrum is thus formed.

scholarly journals On the sensibility of the eye to variations of wave-length in the yellow region of the spectrum

1910 ◽  
Vol 84 (572) ◽  
pp. 464-468
Keyword(s):  
Focal Plane ◽  
Colour Vision ◽  
Arbitrary Element ◽  
Normal Individual ◽  
Wave Length ◽  
Colour Difference ◽  
Orange Yellow ◽  
Yellow Region ◽  
Great Uniformity ◽  
Made In

Dr. Edridge-Green has introduced a method of classifying colour-vision by determining the number of separate parts or divisions in the spectrum within each of which the observer can perceive no colour difference. Movable screens are provided in the focal plane of the spectroscopic telescope, by which the part admitted to the eye is limited and the limits measured in terms of wave-length. Beginning at the extreme visible red, more and more of the spectrum is admitted until a change of colour (not merely of brightness) is just perceptible. This gives the first division. The second division starts from the place just determined, and is limited in the direction of shorter wave-length by the same condition. In this way the whole spectrum is divided into a number of contiguous divisions, or patches, which Dr. Edridge-Green terms monochromatic. It will be observed that the delimitation of these patches includes an arbitrary element depending on the point from which the start is made—in this case the extreme red. “ Tested with this instrument a normal individual will, as a rule, name six distinct colours (viz., red, orange, yellow, green, blue, violet), and will mark out by means of the shutters about 18 monochromatic patches. Occasionally we come across individuals with a greater power of differen­tiating hues, to whom, as to Newton, there is a distinct colour between the blue and violet, which Newton called indigo. Such individuals will mark out a greater number of monochromatic patches, from 22 up to 29. The limited number of monochromatic patches which can be marked out in this way is at first surprising when we consider how insensibly one part of the spectrum seems to shade into the next when the whole of the spectrum is looked at. The number and position of the patches present, however, great uniformity from one case to another.”

Die Beeinflussung der Zellkerne in den Vorkeimen von Dryopteris filix-mas durch rote und blaue Strahlung

1963 ◽  
Vol 18 (7) ◽  
pp. 557-562 ◽  
Author(s):  
Rainer Bergfeld
Keyword(s):  
Protein Synthesis ◽  
Visible Light ◽  
Blue Light ◽  
External Factor ◽  
Wave Length ◽  
Red Light ◽  
Three Dimensional ◽  
Short Wave ◽  
Nuclear Volume ◽  
Short Wave Length

Morphogenesis and differentiation of fern gametophytes (Dryopteris filix-mas) are strongly controlled by light. “Normal” morphogenesis, i. e. formation of two- or three dimensional prothallia, can occur only under short wave length visible light (= blue light). In darkness and under long wave length visible light (= red light) the gametophytes will grow as filaments. The blue light dependent photoreactive system which controls morphogenesis seems to be located in the outer layers of the cytoplasm. The control of morphogenesis is causally connected with the increase of protein synthesis under the influence of blue light.In the present paper the influence of red and blue light on shape and volume of the nucleus in the fully grown basal cell of the young gametophyte of Dryopteris filix-mas has been investigated. In blue light the nuclei are more or less spherical, in red and in darkness they are spindle shaped. If the light quality is changed the shape of the nuclei is only slightly influenced; the nuclear volume, however, is drastically changed: increase of volume in the blue, decrease of nuclear volume in red and darkness. These reversible changes of nuclear volume under the influence of light, which are apparently correlated with changing rates of protein synthesis, are an impressive example for the control of nuclear properties by an external factor via the cytoplasm.

scholarly journals The lunar diurnal variation of atmospheric temperature at Batavia, 1866-1928

1932 ◽  
Vol 137 (831) ◽  
pp. 1-24 ◽  
Keyword(s):  
Heat Flow ◽  
Temperature Variation ◽  
Wave Length ◽  
Barometric Pressure ◽  
Atmospheric Temperature ◽  
Vertical Flow ◽  
Tidal Changes ◽  
Long Time ◽  
Semidiurnal Variation ◽  
Established Fact

The existence of a lunar tide in the earth’s atmosphere is now a well-established fact. It is indicated by a lunar semidiurnal variation of barometric pressure, found at every station for which the necessary reductions have been made. Now a variation of pressure in a gas is in general accompanied by a variation of temperature. The amount of this variation depends on the rate at which heat can flow in the gas, from a region of compression to one of rarefaction, or from the earth or ocean to or from the gas. The maximum variation of temperature corresponds to adiabatic changes of pressure, while if the heat flow can be very rapid, the temperature variation may be reduced almost to zero, corresponding to isothermal changes of pressure. I have shown that the lunar tidal changes of pressure will be almost adiabatic so far as concerns heat flow in the gas , between regions of compression and of rarefaction. The long time available for equalisation of temperature, viz., a quarter of a lunar day, or about 6 hours, is in fact ineffective because of the long wave-length of the tide, the distance between the regions of highest or lowest pressure in any latitude being a quarter of the circumference of the circle of latitude. The temperature variation might be reduced below the adiabatic value if vertical flow of heat, between the air and the ground or ocean, is sufficiently rapid. This point will be discussed in another paper; the conclusion reached is that the vertical flow of heat is unlikely to be important over the land . Hence a temperature variation approaching the adiabatic value is likely to be associated with the lunar atmospheric tide at a land station.

Blue-light Filtering Intraocular Lenses

2012 ◽  
Vol 06 (02) ◽  
pp. 104 ◽  
Author(s):  
Sally Blackmore-Wright ◽  
Frank Eperjesi ◽  
◽  
Keyword(s):  
Circadian Rhythm ◽  
Blue Light ◽  
Colour Vision ◽  
Intraocular Lenses ◽  
Scotopic Vision ◽  
Eye Health

Blue-light filtering intraocular lenses are purported to reduce the incidence of potentially damaging UV and blue light on the retina. This article reviews their background, the proposed benefits on long-term eye health and the possible disadvantages on circadian rhythm, scotopic vision and colour vision.

scholarly journals An X-ray study of the dissociation of an alloy of copper, iron and nickel

1943 ◽  
Vol 181 (987) ◽  
pp. 368-378 ◽  
Keyword(s):  
Quantitative Data ◽  
Reasonable Agreement ◽  
Wave Length ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Lattice ◽  
Cubic Structure ◽  
Average Wave ◽  
Diffraction Effects ◽  
The Way

A description is given of the unusual X-ray diffraction effects shown by the alloy Cu 4 FeNi 3 while it is in the process of splitting up from one face-centred cubic structure into two. Before the formation of the tetragonal structures described by Bradley a state is formed in which each line of a powder photograph is accompanied by quite strong side-bands. An explanation of this is given and is shown to be in reasonable agreement with most of the quantitative data from the X-ray photographs. This explanation is that the original cubic lattice is regularly deformed by the segregation of the different atoms. From the positions of the side-bands the directions of the deformations and their average wave-length can be estimated. The intensities, however, do not fit in with the theory; they do not vary exactly in the way predicted. It is shown, however, that the variation is in closer agreement with this sort of modulation of the structure than with any other, but it has not, so far, been found possible to find any factor that will modify the intensities of the side-bands in the way required.

scholarly journals A quantum theory of colour vision

1921 ◽  
Vol 92 (646) ◽  
pp. 219-232 ◽  
Keyword(s):  
Quantum Theory ◽  
Colour Vision ◽  
Wave Length ◽  
Evolutionary Development ◽  
Selective Absorption ◽  
Philosophical Magazine ◽  
Evolutionary Aspect ◽  
Natural Objects ◽  
The Subject ◽  
The Difference

In a paper on the subject of the Quantum Theory of Vision, issued in the ‘Philosophical Magazine’ (February, 1921), I dwelt on the view that the sensation of light is in every case stimulated by the action of photo-electrons set free in the retina. Further, the energy of the photo-electron being pro­portional to the frequency of the light, the strength of the stimulus produced is the all-sufficient origin of colour sensations. That colour is entirely a cerebral phenomenon is evident. Light, visible and invisible, consists of a uniformly graduated series of wave motions or energies. There is nothing to distinguish one part of the spectrum from another save the difference of wave-length or frequency. But objects in Nature react differently towards these waves: absorbing some, reflecting others, and so the selective effect of natural objects towards light has discovered to the organism a means of improving on mono-chromatic vision: a means of distinguishing objects by their selective absorption and reflection. Our colour sensations were deve­loped solely for this purpose and solely under the influence of the light reflected by natural objects. Hence, a limited number of fundamental sensa­tions being the simplest, if not indeed the only, way of securing the desired end, we would expect that these sensations would be developed so as most effectively to interpret the frequencies met with among natural objects reflecting solar light. The evolutionary development of three highly deve­loped colour sensations according to the extreme and mean regions of the spectrum is the result. Colour sensations, i. e. (white), red, green, and blue were evolved, whereby the whole gamut of the spectrum can be dealt with. In my former paper I restricted my reference to colour vision to this evolutionary aspect of the matter. In the present paper I have something to add respecting the retinal apparatus developed to subserve the end which Nature had in view.

scholarly journals Studies on the physiology of Funaria hygrometrica spore germination. Part IV. The effect of blue and red light on the germination of spores

2015 ◽  
Vol 41 (1) ◽  
pp. 97-106 ◽  
Author(s):  
J. Krupa
Keyword(s):  
Blue Light ◽  
Spore Germination ◽  
Radiation Treatment ◽  
Wave Length ◽  
Red Light ◽  
Funaria Hygrometrica ◽  
The Individual

The effect of radiation with wave-lengths 654 nm and 425 nm on the germination of <i>Funaria hydgrometrica</i> spores has been studied. The wave-length bands used for the radiation treatment were employed for various durations and in various combinations. The effects of red and blue light were different in the individual phases of germination when after an inductive radiation treatment light in the 425 nm wave-length was supplied. Differences in the effect of red and blue light are observable in the "post-effects" land in the germination morphology.

scholarly journals TIPOLOGI PANTAI UNTUK OLAHRAGA SURFING DI PULAU KARAM KECAMATAN KOTO XI TARUSAN KABUPATEN PESISIR SELATAN

JURNAL BUANA ◽  
2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Ardian Syahroni ◽  
Helfia Edial ◽  
Widya Prarikeslan
Keyword(s):  
Wave Length ◽  
Secondary Data ◽  
Sampling Technique ◽  
Descriptive Study ◽  
Primary Data ◽  
Survey Method ◽  
Wave Type ◽  
Mapping Unit ◽  
Wave Characteristics ◽  
Average Wave

This study is purposed to: 1) find out shore typology in Karam Island Koto XI Tarusan district Pesisir Selatan regency, 2) to find out wave characteristics (length & slam index), 3) to find out wave types for surfing activity in Karam Island Koto XI Tarusan district Pesisir Selatan regency.This study was classified into descriptive study with survey method. Data in this study was primary data that came from field observation and secondary data which was collected from related agencies. Mapping unit that used in this study was shore line with study object was shore in Karam Island Koto XI Tarusan district Pesisir Selatan regency. Sample was obtained by purposive sampling technique. Study findings are: 1) shore topology is bura (alluvial coast) and marine coast, 2) average wave length (L0) and average slam height (Hb) are 177.58 m and 1.73 m, respectively, 3) wave types are plunging, spilling, and surging. Shore typology and wave type based on wave height and wave period in area of sample I in Karam Island Koto XI Tarusan district Pesisir Selatan regency is suitable for amateur surfer.

Long Wave Infrared Type II Superlattice Focal Plane Array Detector

2017 ◽  
Vol 67 (2) ◽  
pp. 135 ◽  
Author(s):  
P.C. Klipstein ◽  
E. Avnon ◽  
Y. Benny ◽  
A. Fraenkel ◽  
A. Glozman ◽  
...  
Keyword(s):  
Focal Plane ◽  
Dynamic Range ◽  
Wave Length ◽  
Focal Plane Array ◽  
Array Detector ◽  
Back Side ◽  
Type Ii ◽  
Type Ii Superlattice ◽  
Long Wave ◽  
Long Wave Infrared

The XBn/XBp family of barrier detectors enables diffusion limited dark currents comparable with HgxCd1-xTe Rule-07 and high quantum efficiencies. SCD’s XBp type II superlattice (T2SL) detector contains InAs/GaSb and InAs/AlSb T2SLs, and was designed for the long wave infrared (LWIR) atmospheric window using k · p based modeling of the energy bands and photo-response. Wafers are grown by molecular beam epitaxy and are fabricated into focal plane array (FPA) detectors using standard FPA processes, including wet and dry etching, indium bump hybridisation, under-fill, and back-side polishing. The 640 × 512 pixel, 15 μm pitch, detector goes by the name of ‘Pelican-D LW’ and exhibits a quantum efficiency of ~ 50 per cent with background limited performance at an operating temperature of 77 K. It has a cut-off wave length of ~ 9.5 μm, with a pixel operability of above 99 per cent. The detector gives a very stable image with a residual non uniformity of below 0.04 per cent over its useful dynamic range. A new digital read-out integrated circuit has been designed so that the complete detector closely follows the configuration of SCD’s MWIR Pelican-D detector.

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