BS 4274(1968) : AMD 9200
Superseded
A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.
A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.
SPECIFICATION FOR TEST CHARTS FOR DETERMINING DISTANCE VISUAL ACUITY
08-15-1996
11-23-2012
Specification
1 Scope
2 Definitions
3 Range of letter sizes
4 Indication of letter size
5 Style and selection of letters
6 Spacing of lines
7 Spacing of letters
8 Proportions and line widths of letters
9 Dimensions of Landolt ring characters
10 Dimensions of illiterate E characters
11 Manufacturing tolerances
12 Luminance contrast
13 Lighting requirements
Appendices
A General recommendations on lighting for test charts
B Simple methods of lighting for externally
illuminated charts
Tables
1 Range of letter sizes and numbers of letters per
line
2 Minimum and maximum lengths of each line of letters
3 Summary of recommendations on lighting for test
charts
Figures
1-4 Simple methods of lighting for externally
illuminated charts. Methods 1-4
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