International projectionist (Jan 1959-Dec 1960)
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TABLE III. Lumen Outputs of Simplified H-l ("Suprex") Lamps.
LIGHT AND HEAT WITH
ARC AMPS.
POWER VOLTS
MIRROR
SILVERED MIRROR
POS.-NEG. TRIM
DIAM. (In.)
(No. heat filters)
CENTER
LUMENS
APERTURE o F.
7 nun — o mm
1+0
27i
11 3/8
6,500
1200?
7 mm 6 mm
h2
36
m °
8,600
11+00
7 mm 6 mm
he
$
i»f
10,000
1500
7 mm 6 mm
50
m
11,700
1700
8 mm 7 mm
60
37
m
13,100
1800
8 mm 7 mm
65
3
ii+
14,1+00
1900
8 mm 7 mm
70
m
15,700
2100
9 mm — 8 mm
65
1*0
1^
13,000
1800
9 mm 8 mm
75
^3
ii+
15,000
2000
9 mm 8 mm
80
^5
ii+
16,600
2200
* "Suprex" copper-plated positives, "Orotip C" negatives
(National Carbon Company) F/1.7 coated lenses and 0.600" x 0.825" apertures used.
and 1.20 (semi-directional) reflectance, and from 10 to 130 feet in width. Now, for the lumen values needed for widescreen projection (1/1.85 ratio), the lumens given in the table should be multiplied by 0.74.
We are dealing here with identical
screen widths, not heights; and when widths are the same, the wide screen, having in such a case a smaller area, needs only 3/4 the normal amount of light, on the average. CinemaScope of the same width needs even slightly less light, but because this varies so greatly
with the type of anamorphic attachment employed, we may ignore the difference.
The special value of Table I, however, is its usefulness in estimating with a fair degree of accuracy the arclamp lumen rating needed to obtain either 10 or 4 foot-lamberts on screens of either 85% or 120% center reflectivity. We must keep in mind that output lumens are decreased to about 0.75% of normal by 1/1.85 apertures, and that carbon and lamp manufacturers, to eliminate variable factors and for the sake of uniformity, simplify matters by specifying for the different lamps and carbon trims the screen lumens obtained without shutter, heat filters, or port glass, and with a standard 0.600" x 0.825" aperture and //1.7 coated lens.
Lumen Values for Screen Widths
All you have to do to arrive at a reasonably accurate estimate of the required lamp rating is to ignore aspect ratio in non-anamorphic projection (because lamps are less efficient with the smaller apertures) and look up under the proper heading of Table I the lumen value corresponding to the screen width being used. The lumens found are then multiplied by
TABLE IV
Lumen
Outputs
Of
RotatingPositive Mirror Lamps.
POS.-NEG. TRIM
9 mm 5/16" 9 mm* 5/16" 9 mm* 5/16"
n 11/32" »! 11/32" a 11/32"
0 mm** 7/16" 0 mm** 7/16" 0 mm
1/2"
mm* 3/8" mm* 3/8" mm* 3/8"
mm* 11/32" mm* 11/32" mm 11/32"
mm** 7/16" 1** 7/16" i** 1/2"
1 mm* 3/8" 1 mm* 3/8" 1 mm 3/8"
3.6 mm*-7/16" 3.6 mm*-7/16" 3.6 mm*-7/16" 3^6 mm*-7/16" 3.6 mmJ-1/2" 3:6 mm*-1/2" 3.6 mm*1/2" 3.6 mm*1/2"
ARC POWER AMPS. VOLTS
75 52-58
80 54-59
85 55-60
95 51-57
100 51)-59
110 59-65
125 60-64
130 62-66
135 66-70
110 57-62
115 58-64
120 59-68
95 51-57
100 54-59
110 59-65
125 60-6V
130 62-66
135 66-70
110 57-62
1 1 5 58-64
120 59-68
125
140 145 150 155 160 165
56-6O 58-62 58-62 59-63 59-63 60-64 60-64 62-66
MIRROR DIAM. (In.)
16 16 16
16 16 16
16 16 16
16 16 16
18 18 18
18
18 18
18 18 18
18
18 18 18 18 18 18 18
LIGHT AND HEAT WITH SILVERED MIRROR
Without heat filter
LUMENS
16,000 18,000 19,500
18,500 20,700 22,000
24,000 25,000 26,500
21 ,700 23,100 24,100
21,700 23,700 25,200
27,500 29,200 30,300
24,800 26,500 27,600
20,000?
24,000
26,000
28,000
30,000
32,000
34-, 000
35,500
CENTER
APERTURE
0 F.
2200 2400 2600
2400 2600 2700
2900 3000 3200
2700 2800 2900
2500 2700 2800
3100 3200 3300
2800 3000 3100
2200?
2600?
2800
3000
3200
3400
3600
3700
With dichroic filter
LUMENS
14,400 16,200 17,600
16,700 18,600 19,800
21,600 22,500 23,900
19,500 20,800 21,700
19,500 21 ,300 22,700
24,8oo 26,300 27,300
22,300 23,900 24,800
18,000?
21 ,600
23,400
25,200
27,000
28,800
30,600
32,000
CENTER
APERTURE
0 F.
1200 1300 1400
1300 1400 1400+
1500 1600
1700
i4oo 1500 1500+
1300 1400 1500
1600
1700 1700+
1500
1600 1600+
1200?
1400?
1500
1600
1700
1800
1900
2000
LIGHT AND HEAT WITH "COLD" MIRROR
LUMENS
16,800 18,900 20,500
19,400 21 ,700 23,100
25,200 26,300 27,800
22,800 24,300 25,300
22,800 24,900 26,500
28,900 30,700 31,800
26,000 27,800 29,000
21,000?
25,200
27,300
29,400
31,500
33,600
35,700
37,300
CENTER
APERTURE
0 F.
1300 1400 1500
1400 1500 1600
1700
1700+
1900
1600
1600+
1700
1500 1600 1600+
1800 1900 1900-1
1600 1700 1800
1300?
1500?
1600
1700
1900
2000
2100
220C
* Regular unplated (black) H-l positives. ** "Hitex" positives. All negatives "Orotip". The 7/16" "Orotip Special" may in certain cases be substituted for 1/2" regular "Orotip" negative. F/1.7 coated lenses and 0.600" x 0.825" apertures used in all light measurements. (Aforementioned carbons by National Carbon Co.)
INTERNATIONAL PROJECTIONIST • JUNE 1959