Abstract

The development of a small and inexpensive photometer for determining light intensities and photographic exposures is described. A study is made of the performance of two types of instrument. In a large number of readings by a single observer with the smaller type it was found that the average error in measuring exposures on neutral colored objects was 22% which corresponds to about 7% difference in the density of the photographic image. The larger type had a precision of better than 5% for most of the range.

© 1927 Optical Society of America

Full Article  |  PDF Article

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (12)

Fig. 1
Fig. 1

Typical density curve.

Fig. 7
Fig. 7

Small type of exposure meter.

Fig. 7a
Fig. 7a

Section of tubuler type of exposure meter.

Fig. 9
Fig. 9

Calibration curves.

Fig. 10
Fig. 10

Calibration curves.

Fig. 11
Fig. 11

Calibration of larger instrument.

Tables (3)

Tables Icon

Table 4 Precision of zero setting.

Tables Icon

Table 5 Precision of settings

Tables Icon

Table 6 Precision of readings.