US1258636A - Testing device. - Google Patents

Description

A. J. NEWTON & S. M. FURNALD.

TESTING DEVICE.

Afrucmon man an. 0. I917.

1,258,636. Patented Mar. 5, 19m

FIE- lv INVENTORS,

smng/umrmz z, C

"this specification,

ETED STATES PATENT QFFICE- ALFRED J. NEWTON AND STANLEY M. FURNALD, OF- ROCHESTER, NEW YORK, ASSIGN- O RS TO EASTMAN KODAK COMPANY, OF-ROCHESTER,. NEW YORK, A CORPORATION OF NEW YORK.

1 '0 all whom it may concern:

Be it known that we, ALFRED NEWTON, :1 subject of tl ie'King of Great Britain, and S'rANLEi' M. FURlYALD, a; citizen of I the United States of America, both residing in Rochester, in the county of Monroe and Sta t'e of -New York, have invented certain new and 'iiseful' Improvements in I Testing Devices; and we do hereby declare the following to be In fiill',"cl'ear, and exact'description of the same, reference being'had'to the accompanying drawingg'jforming'a part of ln'd to' the reference-numerals marked thereon.

The object 'of this 'inventionis'to provide mains for testing the'co'rrectnessof one or more of thef'variable' factors 'in' photo- .Iii" the "three-color) process, three color: selection 'n eg'etiyes' of the suh e ct are made or) 'panc'ln'oi'ne'tic 'or color sensitive I lates,

onefthr'o'ugh' a'red light-filter; ano er'a green lighcfiltcltg arid a third through 'a.

blue filter." Anfadditional negativeon a panchromaticlplate' is made 'behlnd a, yellow filter'in the foupcolor process, wh1ch' .co1npens'ates" the "s'ensitiven'ess of th 'e- I photographic plate,- so thatjthe d-ifl'erent colored 'parts'of the subject Twill afi'ecfl'the' plate present to the"eye I I I I Printing" Ipl'ates', I s ch as half -ton'e blocks are made from these ne atrves. Theplate with the same "r la ti 'e intensity that they derived from the" red" s 'e ectionf negative is printed in blue-green ink," technically known as mihu'sf'redQ Thefplate' from the green selctionne'gative is'pr i nt ed i n fminusgreen or magenta lnk, whlle'the' blue sect on plate is printed in minu's-blujeor' yellow Inj'f'four-col'or work a' visual lnminosity plate is printedin 'gray' or black; These different ink'firn'pressions are printed one upon the other so that the final colored picture or reproduction results'fro'm the cooperati n of all the superposed )printings. They cannot, however, cooperate to 'g1ve a correctly colored picture unIeSs'eVery ink impression isof correct density. For example, if we are reproducing aneutral gray object by the th1-ee-color'process"and our filters, inks and plates areall correct, but the exposures 'of'the original negatives are incorrect, we would then fail to get a gray Specification o1 Letterslatent.

TESTING DEVICE,

Application filed March 6, 1917. Serial No. 152,665. I I

reproduction in the final'print because some of the ink impressions'would be wrong.' If the bl ue green ink impression was not sufficient in amount to absorba I correct amount of"re'd, the print would show a reddish tinge" Where it should bc gray; NVhile' We have taken gray as an illustration, other colorsmay be similarly degraded.

The correctness of the ink'impressions depends primarily upon correct densities inl'the color-selection negatives.""Only'when a's'et of negatives is secured; all having the cor- -rect density, will the 'rflest'ofthe'proeess follow easily'fl'But correct] negativesTsnlt only when the exposures 'through"the'ditfei'-'- ent filters bears .a. correct ratio toeach'o'ther. Qonsequently fafdetermi'nation of this ratio 1 's'a"pr1ine' es'entialin alligood worlc'. In 3 the 'few' cases: Where such controlling fa ctors fa's light 'rays," plates," and filters" are allfifstb ndardiied, it iiriiniifacturer of p'hot'ogrgphmf materials can suppl the trade with I su cient date; concerning I e exposure- -raties.- It is,- howeveigheither practicable nor p'ossibl'e'for'himf to"gi'\ e data"cove1'ing all- Iconditions' met in practice 5 The. op'erja'tor "lia'mp's' may 'be quite different from the maneuversstandziid different light filters may be substituted"; 5 or plates of 'Figjire lflis'agplan view of the instrument. *Fig. '21'5 'a"vertical' transverse='-sectio:1- fther'eofwitli'the-testichart-removedl- Fi'g'."3"is"a "perspective view "of'the test 'is a diagrammatic sectional pl-a-n vieiir bf-the-instrnmen't in use shoivin' con-- ven'tionany aba'm'era lens and light filters.

Fig. 5isa diagrammatie'sectional eleva- 'tion'tliereof; f The"'device comprises-ingeneral atest .to allow the test chart..to.be;m oye chart slidable over a background'which does not reflect or emit. actinic light; at 'least'it should not reflect enough light to affect a photographic plate even exposure used in a test. For convenience we shall refer to such a background as black. One particular form of such a background is shownin the drawing. It consists of a rectangular box 1 of opaque material having a longitudinal"rectangular opening 2 in its top or outer face 3. The bottom inner face of the box opposite opening 2 is covered with a la 'er 5 of black velvet or similar dead-blac' material which absorbs substantially all of the incident. light. The box acts as a shade to cut oltt' undesirable lateral light rays. from the velvet. While the velvet alone may sufiice in some cases, thense of a shade is generally preferable. The. other interior surfaces, as well as the-exterior surfaces of; the box, preferably covered witlf'material of negligible light. reflecting; power like; black paper.v In Fig. 2 I have indicated at, 27 v the surfncesrwhrethe ma er mey. e;m-

enough the guides and background are sively into five, different}non oveiilapp ng positions.- Dhese positions are above or opposite the five areasfi, 10,.-11 12 and 13 of-a-gray stripmountedonionegofitheguide gues r3 an jiidieate'tlieposL l ad1acent-opening 12. Each argans slightly o ,if -rh he making h e "osure longer than thewldthof the testchart and .th ou' Ii th filterander; don itions beais appropriate symbolsindicating. the light filters :used when; photographing. the chart in; its. successive. positions. 1 on llustration, such s mbols may be; No Filter, K3 Yellow,-A Red-2B Green, 6 Blue the letters K3,.A, B, and-G-beingthe wellown designations of'.Wratten -filters.

Upon the chart 8 is a neutralrblack and white picture 14-, such as a. ,good; portrait positive on .bromid aper,; showingra full scale of gradation. elow this picturcare three areas, 15, 16, 17, colored with the reg ular printing inks and bearingsuitablejdentificationsymbols such:a s Blue, ,Red, Yi'ellow, these symbols in the present examplobeinga compact way ot'indioating blue green or minus-red ink, magenta or minus-greenink, and yellow or. minus-blue ink respectively. A strip 18 of measured and graded-neutralgray density areas is included onjthegchart adjacent the coloredink. Each density area requires twice the exposureof the next lighten one, although other. ratios could be with the longest In use'thebox is fastened to a copy board with the opening 2 and the chart 8 facing toward the camera 19', as diagrammatically shownin Figs; 4' audit).- The chart 8 is moved to a position over 'the no filter? area 9. One of the same kind of color sensitive plates that are to be used in the process is placed in the camera at 20 and'the latter arranged so that an image of the whole front of the ratiomete'rcan be formed on the plate. Of course, thechart is illuminated by the same, light sources that are-em loyediii the regular color process work; A i' 'eiip'o'su're 'is now made without using any filter. '..This" exposur'e is assumed to be correct 'a idyblein'g the easiefstiof 'all"the exos ass m determine, nvill always be aprqxima Iyaccurate iii'the hands "of an'exfpeiience'd worker. sites we are concerned with,iratigspg elaute amount of exposure, absolii'te acuraey of first'exposure withi w n' i e E e ts' nets' l- 1' :rneieseeteami eimpit u'wkgr'auna will imwt 1 t e. fre'e i a eas -ima e; 1 iirsihw a xp-qge nereeiimpr dirritateem a 2 me e: reyitm filer af e te arid it' r 2' ti teft mfieim e e li bm -s ettu filt r-m y e i i' v ermelyr f iihich sin-heats described: jI

.fEh i-p ha i 8,.i s. n s ei f' ;'i,f ti 22 abowethe "dream; fQifiltris put inposition exposur made; The

. length; of this exposure will lie greater e-nf g ag sae' een m s f th 1 .igql t i u e Qf-fl st. 4 T h,ey 3,. filt er is now replacedby a red "images 'of the chart ja're impressed in proper .would be greatly overexposed when the test was finished. To prevent this trouble, they are'inade' with black symbols on a' deep gray ground, ivhich'nee'ds'a full exposure-,such as isfurnish ed the sum of the successive test exposures, in order to appear satisfactorily in the'final'testp'rint. \Ve consider this arrang'e'ment preferable to making the areas whiteaii'd' moving a mask with chart 8 so that all thea'rea's are covered except the one below the 'chart'.

Thefsen sitiye plate now contains a set of latent images. correspondingto the respective filters,1an'd. resulting from'test, exposures, tl 1 e corrctness"of which the operator has tried a; estimate. Thi s'pllate is made into a negativefrom ,ivhicha positive print. may .be made in. the. usual 'way. It'fis'froin the negatiye '1 this front that we tell whether the ratio of our tri a'l exposilres'is in fact correct.

The printjzonsists-ofifive-jpictures of the chart'S arranged side by's'ide and each located above a s mbolwhich identifies it; for example, the p1cti1re'tliatlras'" resulted from the exposure through the red filter will be If'the O el-mites been animate enough to estimate the exposures correctly thefirst' time, the area 14 and gradation strip 18 will appear of the same density in al the test pictures.

In the print of the picture taken through the red filter, area 15, which bears the word Blue, will be dark and areas 16, 17 very light. In the green filter picture, area 16 will be dark and the others lighter, while area 17 will be the darkest in the blue filter picture. The K3 picture shows the areas with visual luminosity. The areas 15, 16, and 17 thus test the coordination of the filters and inks.

If, as is probable, the estimated test ratio of exposures was somewhat incorrect, the pictures on the negative or in the test print will show the fact. For example, if the exposure through the green screen was too short, the resulting picture of 14 and the strip 18 in the final print will be too dark. If the exposure was too great, the resulting picture will be too light. This gives only a qualitative indication of the error, but inspection of such a picture is preferred by some workers. The pictures of the graded density strips 18 will, however, give a quantitative idea of the error when the densities in one picture are compared with those in another. For example, if the second density of the strip in a correct picture is equal to ..k' 'e'p' h rrn xaft iq other factors such asthe-filters'lintil the ptc- .tures sl owequal densities j while starve desert-fear at; iii-$889871 embodiment of our invention, many modi the firstdensity or the st'rip man underexposed picture, then ,theexposure in' the latter case was only half what it should have been. l I ;:;:2 :1 From the test print the operator has now learned the correct factors "governing his work and is Ina-"position topro'ce'ed: in seduced froin-the'p'rior one's;"'- s ["lhe test itself, whilesomewhat complieated to describe, 'is in practice very short and simple. Ifdesired, the'itest maygbe further shortened by omitting the making of a pesitive print, 'the"ne'cess'ary. information being readily deducible.from the test negatire. It should also be noted that the order in which the exposures are made behind the different filters Cisf immaterial, provided f the chart 8 is located above thproper ideiitification symbols durin each exposure.

wins-a the ranged iheihsrraiheiag'eiroaia fications falling within the scope of the appended claims will readily occur tothose skilled in the art.

We claim:

1. A photographic testing device including a black background and a member movable to selected positions thereover bearing a. test area whereby the area may be photographed in successive positions under diiferent conditions.

A photographic testing device including a black background, a member bearing a test area movable over the background to selected positions and identification symbols arranged along the background to indicate said posit-ions.

3. In a photographic testing device a L-iack background comprising an area of black material and means for shading the same from undesirable lateral light rays, and a test chart movable across said background.

4.. In a photographic testing device a background composed of a box of opaque material having an opening in one face, and having its inner face opposite the opening covered with dead-black fabric and a test chart movable across said background.

5. A photographic testing device including a black background, guides thereon and 0, thereon.

- co ie agoi't iui iie obtained :01-

a test chart movable over the background along said guides. 5

ii. A photographic testing device includa black background, guides thereon, a test chart movable over the background along said guidesto selected test positions and photo raphically reproducible identification sym ols adjacent each position.

7. A photographic testing device includin g a black background, a testing chart XllOY- able thereon to selected positions and identifn ation symbols on a deep gray ground adjacent said positions.

H. A photographic testing device including a black background and a test chart u-ovable iherern'er, said chart bearing a neutral black and white picture, areas of colored ink with identification symbols thereon, and astri of predetermined graded neutral gray ensities. I

9. photogra hic'testing device including a bla'c-k ac ground and a test chart ,moyable thereorer, said chart bearing a test strip of predetermined-graded neutral gray densities. p

, 10ml photographictesting device includfing., a black background and a test chart 'movablethereover, said chart bearing areas ofcoloredinlis having identification symbols in" D pli otogni'phic testiiig device includ- 'l'l A and' a test chart movable thereover, said chart bearing a graded, neutral, black and white image.-

12. In a ratiometer for deterrnining the ex posure ratio in three and four-color proccss work, the combination of a black background, a test chart slidable thereover to selected test positions, each position corrc spending to the use of a different light filter,

grayground mounted alongone'guide adja-" cent each positionito'v 'designatefthe filter corres )on ding'to'thep'osifion,

n testimony war "fflye havesig'ned this specification in thepzfs'elioeof two witnesses this 28 da' of February, 1917 Boehester,

N. Y. I

A. J..NEWTON.

v V S'1fANLEYM.'-FURNALD. Witnesesf R? 1 mm;

five cent; esch, by addressing thedozjinilssion'er ot l'gtentl.

wuhing'tonj l). 0. i

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