GB581408A - Improvements in photometric exposure meters for photographic apparatus - Google Patents
Improvements in photometric exposure meters for photographic apparatusInfo
- Publication number
- GB581408A GB581408A GB1950343A GB1950343A GB581408A GB 581408 A GB581408 A GB 581408A GB 1950343 A GB1950343 A GB 1950343A GB 1950343 A GB1950343 A GB 1950343A GB 581408 A GB581408 A GB 581408A
- Authority
- GB
- United Kingdom
- Prior art keywords
- comparison
- negative
- aperture
- projected
- piece
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000463 material Substances 0.000 abstract 2
- 238000005259 measurement Methods 0.000 abstract 1
- 239000000123 paper Substances 0.000 abstract 1
- 239000011088 parchment paper Substances 0.000 abstract 1
- 230000035945 sensitivity Effects 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/10—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void
- G01J1/12—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void using wholly visual means
- G01J1/122—Visual exposure meters for determining the exposure time in photographical recording or reproducing
- G01J1/124—Visual exposure meters for determining the exposure time in photographical recording or reproducing based on the comparison of the intensity of measured light with a comparison source or comparison illuminated surface
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Eye Examination Apparatus (AREA)
Abstract
581,408. Comparison photometers and exposure meters. PEARSON, A. Nov. 22, 1943, No. 19503. [Classes 97 (i) and 98 (i)] A comparison photometer or projection printing exposure meter comprises a ground a of semi-opaque paper on to which the light transmitted by the negative is projected, and having beneath it a white card in which is cut a small aperture k through which the comparison light is projected. A tube b extends below the aperture k and contains diffusing material, such as a piece'of parchment paper, and a piece of film having the transparency of the high lights of the negative. A lamp c is the comparison light and may be tinted blue or covered with blue-tinted material. Its intensity is controlled by two resistances e, f, the latter being adjusted, by means of a knob g - geared to scales h, i, giving readings of different sensitivities. A third scale j may be provided. The resistance e is varied to suit any particular circumstances such as voltage fluctuation or the particular desired intensity. The resistance f provides the desired adjustment of luminosity at the aperture b for matching purposes, and is graduated from measurements and adjustments made with a negative of a normal subject. Specification 380,430, is referred to.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1950343A GB581408A (en) | 1943-11-22 | 1943-11-22 | Improvements in photometric exposure meters for photographic apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1950343A GB581408A (en) | 1943-11-22 | 1943-11-22 | Improvements in photometric exposure meters for photographic apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB581408A true GB581408A (en) | 1946-10-11 |
Family
ID=10130435
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1950343A Expired GB581408A (en) | 1943-11-22 | 1943-11-22 | Improvements in photometric exposure meters for photographic apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB581408A (en) |
-
1943
- 1943-11-22 GB GB1950343A patent/GB581408A/en not_active Expired
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