Geologic photography

The paper is the study of geologic photography. The conclusions follow: (1) Use the proper equipment at the proper time, (2) Be accurate in focusing, (3) Be accurate in exposure calculations, (4) An electric exposure meter is recommended, (5) Use color film to bring out detail, (6) Color photographs should be taken during the period from two hours after sunrise until two hours before sunset unless artificial lighting is supplied, (7) Use of color film should be justified, (8) Use a scale or some common object for size comparison, (9) Use care in selecting microscope objectives and eyepieces when taking photomicrographs, (10) A 32 mm. objective with a lOx eyepiece will produce an approximate magnification of 50x and this will be sufficient for the study of sand grains, (11) If photographing thin sections, a higher magnification above 50x may be required, and (12) It is a better procedure to re-take a photograph than correct mistakes during the developing and printing processes.