Download Report - Academy of Motion Picture Arts and Sciences
Download Report - Academy of Motion Picture Arts and Sciences Download Report - Academy of Motion Picture Arts and Sciences
X is the reproduction of a color chart made from ;;t; il;.Jubl. colott purchased from Windsor ;# fiJiv"t; "na .u" be duplicated bv using the .o1"t. ut named in the chart' These'pigments were ;.J"; J;;;ribed bv Mr' Lovd- A' Jones in his if.t ;;;;t-;; " prto,ographic Reflecting Power of "#r"t.['oU..it; in ti.'Ttutt'' of the So-ciety of il4;,t"" pi.i"t. Engineers, Vol' Xl', No' 31' page lE+. lizz. Thev were selected for our chart be- .J"J. *o.t tt. had done with them !n con- ;;;;';iit "irtt. ..u.rul light sources as described in that "' Paper' lffi;" X is omitted because it is in- colors not p"*ifi?--a i.prod,r.. accurately' It. shows in a iit.i. itt. following: No' 1, Prussian Blue; 2' ili;;;;';l J, cJtut, Bluei 4, PurPle.Lake; 5' d;;;Vt"t;i ;2, cobult Green ; 7' Em-e11td Green I t""L;"; ihro*"; 9' Cadmium Yellow; 10' V.rri* Oirt*;- tl, Otu"gt Vermillion; 12' Vermillion : 13, White ; 14, Black') Fieur. XI is a photograph of- this 4GNe Fl6.Ig MilE'o'reato ':s:T E.Iffitrdtr 65flI"{'ia' rt-esril-1too | | ./-- - | | | /l_ ,1 ,/'r .2',r' 7/ 7 lo A6 FIG.E PS4nd^rcr's€&c sftF|seF@&l@e ais! ,/, ttrl tttl t q2 .f,) ,r{ ,/ /r/ -: FIG.&I WHft S Ptffi$&HGg&EAC IUiEN E*t"faw, itll tttl ,/"i !Ul.@ a*#k*a: .r.. ,44 1.., 2 :l f"f..i. t "ta P^NCNROX^rc.O,sMLE .;?/ "f/ I o8,/ a l.+,/ ARO | .,/ llti- I I I I .ob EEoo zeo The relation between the visual light as expressed i" i"*.** and the current' vo-]-t3-e-e and,watts used at the arc is given in Figures XllI to i(vr' Fisures XIII and XIV show the change in light ,. ,ttE and voltage at the arc ate increased' ""tt""t *ff,. lumen is the unit of luminous flux equal to the fr"i.-iti"a in a unit solid angle bv a point source oi- one canat. power' The lumens of a li-ght source ii.".i""i^T.-r.-2.6 ti-t" the mean spherical candle power of the light source' t46) This is shown clearly in Figure XV by plotting the light or lumens against the watts.at the arc *fti.tt-i. the product of the currettt and voltage at the - arc. Here, again, it is seen that if the watts at the arc are doublJd ih" ir,.r.,,. in light is considerably more than double. This gain in efficiency by using more power at
the arc either by increasing the current or voltage at the arc is again illustrated in Figure XVI where the visual light efficiency in lumens per watt is plotted against the watts at the arc. ' The curves in the above figures have all been based on voltage and watts at the arc, A certain amount of external resistance is required for "ballast" with the type of side arc lamp used in the moving picture studio. Therefore, to obtain the overall efiftciency the line watts and line volts must be used. This has been computed for the twin arc lamp and the results are given in Figures XVII and XVIII. Figure XVII shows for both the white Flame and Panchromatic "O" Carbon Arcs the effect on the light or lumens and Figure XVIII shorvs for these same carbon arcs the effect on the overall efficiency or lumens per line watt of burning N ^rb@r l"//' a &r/ .l ffi cnPesM UNE f/ v r '/ 7 rl ,/ P9 7 /- .e2 / them in a twin arc lamp on a 110 volt line under various conditions of current and voltage across the two arcs. It is quite evident that a low arc voltage for a given current and line wattage gives much less light and a lower efficiency than a high arc voltage under the same conditions. For example, take a current of I /, I // ol/ ,// , /,1 ts ""J. / t, ',/ u E 6 // u/ / 2 I ,f f/ /q v .9 40 amperes at the lamp and 4400 line watts with panchromatic "O" carbons (See Figures XVII and XVIII), if the voltage across the arcs themselves was only 60 volts, that is 30 volts across each arc (a condition giving a short arc length), the lumens would be 138,000 and the lumens per line wat 31.3 but if the voltage across the arcs themselves was 100 volts, that is 50 volts across each arc (a condition giving a long arc length) the lumens would be 292,000 or more than doubled for exactly the sa:me line watts as aboae and the lumens per line watt or overall efficiency would be 66.3 or more than doubled. It can also be seen that if the current is increased and the voltage across the carbons kept the same (that is the arc length the same) the efficiency of the lamp and total light increase materially. For example, for a current of 30 amperes and 80 volts across the arcs with panchromatic "O" carbons (40 volts across each arc) the lumens are 138,000 and the lumens per line watt 41.8 but {or a current of 50 amperes and B0 volts across the arcs, the lumens have increased to 292,000 and the lumens per line watt or efficiency increased to 53.1 These curves indicate very clearly the improvements possible in the capacity and efficiency of the side arc lamp by a proper regulation of the lamp resistance and arc length. The limiting factors on current are the capacity of the lamp wiring and carbons. The limiting factor on arc voltage or arc length is the steadiness of the flame. It might be added that the higher the current up to the capacity of the carbon, the steadier the flame for the same arc length. The National Panchromatic "O" Carbon Arc, because of the greater amount of yellow, orange and red light gives, as shown in the figures, more visu.al light for the same watts than the white flame carbon arc. The white flame carbon arc on the other hand, because of the larger proportion of blue and violet rays has a higher photographic efficiency for the same watts than the panchromatic "O" carbon but, as already indicated does not bring out the reds and yellows as well as the panchromatic "O" carbons. This difference in photographic power is comparatively small, being approximately in the ratio of 5 to 4. In photographing yellow, orange or red materials the photographic power of the panchromatic "O" carbons for these colors is greater in the ratio of approximately 6 to 5 than the photographic power of the white flame carbon. It is hoped that a study of the photographs and curves in the paper will aid materially in applying the White Flame and Panchromatic "O" Carbon Arcs to the light problems of the moving picture industry. DISCUSSION ON MR. DOWNS,PAPER Mn. Balr,: In the discussion of Mr. Downs' paper I would like to urge the men present to tend toward a discussion of the practical use of the 147l
- Page 1: ACADEMY RE,PORTS lNo. 1l INCAI{T}ES
- Page 4 and 5: Academy of Copyrighted By the Motio
- Page 6 and 7: INTRODUCTORY STATEMENT The followin
- Page 8 and 9: ment supplied {or carrying out this
- Page 10 and 11: was discussed at some length with t
- Page 12 and 13: lamp or globe replacements, as comp
- Page 14 and 15: COMMENTS ON LABOR COSTS Although no
- Page 16 and 17: amount to be moved. Undoubtedly, th
- Page 18 and 19: g "Heat is too great and leak light
- Page 20 and 21: "In regard to value, the tests have
- Page 22 and 23: ROOSEVELT The following'scenes were
- Page 24 and 25: QursrroN: What color filters were u
- Page 26 and 27: morning. But now, through the balan
- Page 28 and 29: portant fields for experiment in co
- Page 30 and 31: make-up is a great help in keeping
- Page 32 and 33: is best defined by stating the rela
- Page 34 and 35: photometric curves, they serve to s
- Page 36 and 37: divided into three equal portions r
- Page 38 and 39: We can now apply the various fundam
- Page 40 and 41: of energy radiated by tungsten in t
- Page 42 and 43: high temperatures and it is quite h
- Page 44 and 45: to reduce this radiation is to use
- Page 46 and 47: FIGURE V] 16 mm. High Intensitv Whi
- Page 50 and 51: Carbon Arc and Incandescents in the
- Page 52 and 53: Since there is a steady diminution
- Page 54 and 55: to refer to a test which was recent
- Page 56 and 57: the plane perpendicular to the line
- Page 58 and 59: lenses used in motion picture photo
- Page 60 and 61: ':t FINAL SESSION OF THE ACADEMY I
- Page 62 and 63: tubes have been practically discard
- Page 64 and 65: lended together to more efficiently
- Page 66 and 67: ought together all the various Bran
- Page 68 and 69: matographers and the Society of Mot
- Page 70 and 71: T Y P E o F N C .at N D E C E N T E
- Page 72 and 73: T Y P E F N C o N D E c E N T E a U
- Page 74 and 75: o T Y P E F N C n N DESC (NOT FOR S
- Page 76 and 77: TYPES OF INCANDESCE.NT EQUIPMENT Me
- Page 78 and 79: QUALITY OF ILLUMINATION EXPERIMENTA
- Page 80 and 81: BIBLIOGRAPHY "Effective Application
- Page 82: PRODUCERS E. II. Allen E. M. Asher
X is the reproduction <strong>of</strong> a color chart made from<br />
;;t; il;.Jubl. colott purchased from Windsor<br />
;# fiJiv"t;<br />
"na .u" be duplicated bv using the<br />
.o1"t. ut named in the chart' These'pigments were<br />
;.J"; J;;;ribed bv Mr' Lovd- A' Jones in his<br />
if.t<br />
;;;;t-;;<br />
" prto,ographic Reflecting Power <strong>of</strong><br />
"#r"t.['oU..it; in ti.'Ttutt'' <strong>of</strong> the So-ciety <strong>of</strong><br />
il4;,t"" pi.i"t. Engineers, Vol' Xl', No' 31' page<br />
lE+. lizz. Thev were selected for our chart be-<br />
.J"J. *o.t tt. had done with them !n<br />
con-<br />
;;;;';iit "irtt. ..u.rul light sources as described in<br />
that "' Paper'<br />
lffi;" X is omitted because it is in- colors not<br />
p"*ifi?--a i.prod,r.. accurately' It. shows in a<br />
iit.i. itt. following: No' 1, Prussian Blue; 2'<br />
ili;;;;';l J, cJtut, Bluei 4, PurPle.Lake; 5'<br />
d;;;Vt"t;i ;2, cobult Green ; 7' Em-e11td Green I<br />
t""L;"; ihro*"; 9' Cadmium Yellow; 10'<br />
V.rri* Oirt*;- tl, Otu"gt Vermillion; 12' Vermillion<br />
: 13, White ; 14, Black')<br />
Fieur. XI is a photograph <strong>of</strong>- this<br />
4GNe<br />
Fl6.Ig<br />
MilE'o'reato<br />
':s:T<br />
E.Iffitrdtr<br />
65flI"{'ia'<br />
rt-esril-1too<br />
| | ./-- - | | | /l_<br />
,1 ,/'r<br />
.2',r'<br />
7/ 7<br />
lo<br />
A6<br />
FIG.E<br />
PS4nd^rcr's€&c<br />
sftF|seF@&l@e ais!<br />
,/,<br />
ttrl<br />
tttl<br />
t<br />
q2<br />
.f,)<br />
,r{<br />
,/<br />
/r/<br />
-:<br />
FIG.&I<br />
WHft S Ptffi$&HGg&EAC<br />
IUiEN<br />
E*t"faw,<br />
itll<br />
tttl<br />
,/"i<br />
!Ul.@<br />
a*#k*a:<br />
.r..<br />
,44 1..,<br />
2 :l<br />
f"f..i.<br />
t<br />
"ta<br />
P^NCNROX^rc.O,sMLE<br />
.;?/<br />
"f/<br />
I o8,/<br />
a<br />
l.+,/<br />
ARO<br />
| .,/<br />
llti-<br />
I<br />
I<br />
I<br />
I<br />
.ob EEoo zeo<br />
The relation between the visual light as expressed<br />
i" i"*.** <strong>and</strong> the current' vo-]-t3-e-e <strong>and</strong>,watts used<br />
at the arc is given in Figures XllI to i(vr'<br />
Fisures XIII <strong>and</strong> XIV show the change in light<br />
,. ,ttE <strong>and</strong> voltage at the arc ate increased'<br />
""tt""t<br />
*ff,. lumen is the unit <strong>of</strong> luminous flux equal to the<br />
fr"i.-iti"a in a unit solid angle bv a point source<br />
oi- one canat. power' The lumens <strong>of</strong> a li-ght source<br />
ii.".i""i^T.-r.-2.6 ti-t" the mean spherical c<strong>and</strong>le<br />
power <strong>of</strong> the light source'<br />
t46)<br />
This is shown clearly in Figure XV by plotting<br />
the light or lumens against the watts.at the arc<br />
*fti.tt-i. the product <strong>of</strong> the currettt <strong>and</strong> voltage at<br />
the - arc.<br />
Here, again, it is seen that if the watts at the arc<br />
are doublJd ih" ir,.r.,,. in light is considerably<br />
more than double.<br />
This gain in efficiency by using more power at