The dark squares are translucent. Used as an alternative to simple grids for area of specimen determination and particle counting. Alternative light and dark squares help to reduce eyestrain.
The ratio of large to small squares is 9:1. Originally designed for hematology, they can be utilized for rapid counting of any evenly spread field of particle.
References:
1. American J. of Clin. Pathol. Vol.20, 1950, page 1079. "Time Saving Device For Counting Reticulocyte." G.Brescher and Schneiderman.
2. Practicle Haemotology – J.D. Dacy. Published by J.A. Churchill. 2nd Edition 1956 page 25. Pattern
Description NE57 Miller 7 x 7mm grid. Glass sandwich. Dia.
16mm 19mm 21mm
Whipple Grid – NE29
Originally designed for water particle analysis, but may be used for other aspects of particle counting. Grid showed: Ratio of full square to smallest is 50:1. Area is 2500:1 Reference: Microscopy of Drinking Water. Pattern
Description NE29
Whipple grid 100 squares in 7mm area. Surface chrome image.