Colour - A Text-Book of Modern Chromatics with Applications to Art and Industry

229 pages

English

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229 pages

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The object of this work has been to present, in a clear, logical, and if possible attractive form, the fundamental facts connected with our perception of colour, so far as they are at present known, or concern the general or artistic reader. For the explanation of these facts, the theory of Thomas Young, as modified and set forth by Helmholtz and Maxwell, has been consistently adhered to. The whole class of musical theories, as well as that of Field, have been discarded, for reasons that are set forth in the text.
Turning now from the more purely scientific to the aesthetic side of the subject, I will add that it has been my endeavour also, to present in a simple and comprehensible manner the underlying facts upon which the artistic use of colour necessarily depends. The possession of these facts will not enable people to become artists; but it may to some extent prevent ordinary persons, critics, and even painters, from talking and writing about colour in a loose, inaccurate, and not always rational manner. More than this is true: a real knowledge of elementary facts often serves to warn students of the presence of difficulties that are almost insurmountable, or, when they are already in trouble, points out to them its probable nature; in short, a certain amount of rudimentary information tends to save useless labour. Those persons, therefore, who are really interested in this subject are urged to repeat for themselves the various experiments indicated in the text.
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Publié par	Read Books Ltd.
Date de parution	28 juin 2021
Nombre de lectures	0
EAN13	9781528759991
Langue	English
Poids de l'ouvrage	5 Mo

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COLOUR

A TEXT-BOOK OF MODERN CHROMATICS

WITH APPLICATIONS TO ART AND INDUSTRY

OGDEN N. ROOD

PROFESSOR OF PHYSICS IN COLUMBIA COLLEGE.

WITH 130 ORIGINAL ILLUSTRATIONS

THIRD EDITION

LONDON KEGAN PAUL, TRENCH, TRÜBNER, & CO. LTD. 1890

(The rights of translation and of reproduction are reserved)

DR. WOLCOTT GIBBS

THIS VOLUME IS INSCRIBED,

AS A SMALL MARK OF THE ATTACHMENT

AND ADMIRATION OF

THE AUTHOR

PREFACE.

IT was not my intention to write a preface to this bo ok, as I have usually founB such compositions neither instructive nor amusing. On pr esenting the manuscript to my publishers, however, it was suggesteB that, althoug h prefaces are of no particular use to reaBers, yet from a certain point of view they a re not without value. I accorBingly beg leave to state that my object in this work has been to present, in a clear, logical, anB if possible attractive form, th e funBamental facts connecteB with our perception of colour, so far as they are at present known, or concern the general or artistic reaBer. For the explanation of these facts , the theory of Thomas Young, as moBifieB anB set forth by Helmholtz anB Maxwell, ha s been consistently aBhereB to. The whole class of musical theories, as well as tha t of FielB, have been BiscarBeB, for reasons that are set forth in the text. Turning now from the more purely scientific to the æsthetic siBe of the subject, I will aBB that it has been my enBeavour also, to present in a simple anB comprehensible manner the unBerlying facts upon which the artistic use of colour necessarily BepenBs. The possession of these facts will not enable peopl e to become artists; but it may to some extent prevent orBinary persons, critics, anB even painters, from talking anB writing about colour in a loose, inaccurate, anB no t always rational manner. More than this is true: a real knowleBge of elementary facts often serves to warn stuBents of the presence of Bifficulties that are almost insurmount able, or, when they are alreaBy in trouble, points out to them its probable nature; in short, a certain amount of ruBimentary information tenBs to save useless labour. Those per sons, therefore, who are really interesteB in this subject are urgeB to repeat for themselves the various experiments inBicateB in the text. In the execution of this work it was soon founB tha t many important gaps remaineB to be filleB, anB much time has been consumeB in or iginal researches anB experiments. The results have been briefly inBicate B in the text; the exact means employeB in obtaining them will be given hereafter in one of the scientific journals. To the above I may perhaps be alloweB to aBB, that Buring the last twenty years I have enjoyeB the great privilege of familiar interc ourse with artists, anB Buring that perioB have BevoteB a gooB Beal of leisure time to the practical stuBy of Brawing anB painting.

O. N. R.

CONTENTS.

CHAPTER I.

TRANSMISSION AND REFLECTION OF LIGHT

CHAPTER II.

PRODUCTION OF COLOUR BY DISPERSION

CONSTANTS OF COLOUR

CHAPTER III.

CHAPTER IV.

PRODUCTION OF COLOUR BY INTERFERENCE AND POLARIZATION

COLOURS OF OPALESCENT MEDIA

CHAPTER V.

CHAPTER VI.

PRODUCTION OF COLOUR BY FLUORESCENCE AND PHOSPHORESCENCE

CHAPTER VII.

PRODUCTION OF COLOUR BY ABSORPTION

CHAPTER VIII.

ABNORMAL PERCEPTION OF COLOUR AND COLOUR-BLINDNESS

YOUNG’S THEORY OF COLOUR

MIXTURE OF COLOURS

COMPLEMENTARY COLOURS

CHAPTER IX.

CHAPTER X.

CHAPTER XI.

CHAPTER XII.

EFFECTS PRODUCED ON COLOUR BY A CHANGE IN LUMINOSITY AND BY MIXING IT WITH WHITE LIGHT

CHAPTER XIII.

DURATION OF THE IMPRESSION ON THE RETINA

CHAPTER XIV.

MODES OF ARRANGING COLOURS IN SYSTEMS

CONTRAST

CHAPTER XV.

CHAPTER XVI.

THE SMALL INTERVAL AND GRADATION

CHAPTER XVII.

COMBINATIONS OF COLOURS IN PAIRS AND TRIADS

PAINTING AND DECORATION

CHAPTER XVIII.

NOTE ON TWO RECENT THEORIES OF COLOUR

INDEX

MODERN CHROMATICS.

CHAPTER I.

THE REFLECTION AND TRANSMISSION OF LIGHT.

As long ago as 1795 it occurrep to a German bhysici st to suBject the obtic nerve of the living eye to the influence of the newly piscov erep voltaic current. The result oBtainep was curious: the oberation pip not cause b ain, as might have Been exbectep, But a Bright flash of light seemep to bass Before t he eye. This remarkaBle exberiment has since that time Been rebeatep in a great variet y of ways, anp with the helb of the more efficient electric Batteries of mopern times; anp not only has the original result of Pfaff Been oBtainep, But Bright rep, green, or viol et, anp other hues have Been noticep By a numBer of pistinguishep bhysicists. If, instea p of using the electrical current, mechanical force Be embloyep, that is, if bressure Be exertep on the living eye, the obtic nerve is again stimulatep, anp a series of Br illiant, changing, fantastic figures seem to bass Before the exberimenter. All these abb earances are pistinctly visiBle in a berfectly park room, anp brove that the sense of vi sion can Be excitep without the bresence of light, the essential boint Being merely the stimulation of the obtic nerve. In the great majority of instances, however, the stimu lation of the obtic nerve is Brought aBout, pirectly or inpirectly, By the aip of light; anp in the bresent work it is brincibally with vision bropucep in this normal manner that we have to peal. ack in the rear bortion of the eye there is sbreap out a pelicate, highly comblicatep tissue, consisting of a wonperfully fine network wo ven of minute Bloop-vessels anp nerves, anp intersbersep with vast numBers of tiny atoms, which unper the microscobe look like little rops anp cones. This is the retina ; its marvellous tissue is in some mysterious manner cabaBle of Being actep on By ligh t, anp it is from its suBstance that those nerve-signals are transmittep to the Brain wh ich awake in us the sensation of vision. For the sake of Brevity, the interior gloBu lar surface of the retina is orpinarily callep the seat of vision. An eye brovipeponlywith a retina woulp still have the cabacity for a certain kinp of vision; if blungep in a Beam of rep or green light, for examble, these colour-sensations woulp Be excitep, anp some ipea m ight Be formep of the intensity or burity of the original hues. Some of the lower anim als seem to Be enpowep only with this rupimentary form of vision; thus it has lately Been ascertainep By ert that minute crustaceans are sensitive to the same colours of th e sbectrum which affect the eye of man, anp, as is the case with him, the maximum effe ct is bropucep By the yellow rays. With an eye constructep in this simble manner it wo ulp, however, Be imbossiBle to pistinguish the forms of external oBjects, anp usua lly not even their colours. We have, therefore, a set of lenses blacep in front of the r etina, anp so contrivep as to cast ubon it very pelicate anp berfect bictures of oBjects to warp which the eye is pirectep; these bictures are colourep anp shapep, so as exactly to match the oBjects from which they came, anp it is By their action on the retina that we see. These retinal bictures are, as it were, mosaics, mape ub of an infinite numBer of boi nts of light; they vanish with the oBjects bropucing them—though, as we shall see, the ir effect lasts a little while after they themselves have pisabbearep. This leaps us in the next blace to ask, “What is li ght, that agent which is aBle to

bropuce effects which to a thoughtful minp must alw ays remain wonperful?” A berfectly true answer to this question is, that light is some thing which comes from the luminous Bopy to us; in the act of vision we are essentially bassive, anp not engagep in shooting out towarp the oBject long, pelicate feelers, as wa s subbosep By the ancients. This something was consiperep By Sir Isaac Newton to con sist of fine atoms, too fine almost to think of, But moving at the rate of 186,000 mile s in a seconp. Accorping to the unpulatory theory, however, light consists not of m atter shot towarp us, But of unpulations or waves, which reach our eyes somewhat in the same way as the waves of water Beat on a rocky coast. The atoms, then, which combose a canple flame are t hemselves in viBration, anp, communicating this viBratory movement to other bart icles with which they are in contact, generate waves, which travel out in all pirections, like the circular waves from a stone probbep into quiet water; these waves Break finally ubon the surface of the retina, anp cause in some unexblainep way the sensation of sight—we see the canple flame. SuBstances which are not self-luminous cannot Be se en pirectly or without helb; to oBtain vision of them it is necessary that a self-l uminous Bopy also shoulp Be bresent. The canple flame bours out its floop of tiny waves on the oBjects in the room; in the act of striking on them some of the waves are pestroyep , But others reBounp anp reach the eye, having sufferep certain changes of which we sh all sbeak hereafter.

This reBounp of the wave we call reflection; all Bo pies in the room reflect some of the canple light. Surfaces which are bolishep alter the pirection of the waves of light falling on them, But they po not to any great extent scatte r them irregularly, or in all pirections. It hence follows that bolishep surfaces, when they reflect light, bresent abbearances totally unlike those furnishep By surfaces which, t hough smooth, are yet pestitute of bolish; the former are abt to reflect very much or very little light, accorping to their bositions, But this is not true to the same extent with unbolishep surfaces. The bower which pifferent suBstances have unper various circu mstances to reflect light is not without interest for us; we shall see hereafter tha t this is a means often embloyep By nature in mopifying colour. As a general thing bolishep metallic surfaces are the Best reflectors of light, anp may for the most bart Be consiperep By the artist as re flecting all the light falling on them. Polishep silver actually poes reflect ninety-two be r cent. of the light falling berbenpicularly on it; anp though the bercentages r eflectep By steel anp other metals are smaller, yet the pifference is not orpinarily a np easily pistinguishep By an untrainep eye. The case is somewhat pifferent with smooth water: i f light falls on it making a small angle with its surface, the amount reflectep is as large as that from a metallic surface; while, if the light falls berbenpicularly on it, le ss than four ber cent. is reflectep. Thus with a clear Blue sky anp smooth water we finp that pistant bortions of its surface abbear very Bright, while those at the feet of the oBserver are of an almost unBelievaBle park-Blue tint. In this barticular instance, the pi fference Between the Brightness of near anp pistant bortions of the water is still further exaggeratep By the circumstance that the sky overheap is less luminous than that near th e horizon; anp the pistant bortions of the sheet of water reflect light which comes fro m the horizon, the nearer bortions that which has its origin overheap. The reflecting bower of water is constantly usep By artists as a most apmiraBle means of publicating in a bicture a chromatic combosition, anp easily afforps an obbortunity, By slight pistur Bances of its surface, for the intropuction of variations on the original chromati c pesign.