Details of exhibit
- Exhibition:
- 1906 Fifty-first Annual Exhibition of the Royal Photographic Society of Great Britain
- Exhibit title:
- Gradation Photometer
- Exhibitor:
- Wratten & Wainwright, Ltd.
- Section:
- Scientific and Technical Photography and its Application to Processes of Reproduction. By Invitation from the Council
- Exhibit No.:
- [197B]
- Description:
- Designed by C. E. Kenneth Mess, B.Sc.
In ordinary plate-testing the speed is obtained by the measurement of the densities obtained by developing a plate which has been exposed behind a rotating sector wheel. A curve is then plotted of these densities against the logarithmic exposure.
The speed and development factors are then obtained from the position and slope of the straight line portion of this curve.
In the instrument shown these result are obtained direct from the scales after one setting of the instrument, without separate measurements or calculation. This is obtained by matching five densities at once against a series of sliding wedges arranged so that their densities must always fall in a straight line on the curve, but at various slopes.
On exhibition only till the end of September. - Exhibit type:
- Photograph
- Process:
- [Not Listed] ()
- Award:
- none
