When light is well distributed and diffuse with no extremes of surface brightness, the eye is practically independent of illumination intensity within ordinary lighting ranges¶
Claim · All claims
Evidence · 1 study · causalr2·q3
Currency · newest study 1917 · not yet checked against its sources · not reviewed by a person
Subclaims¶
Reading the evidence codes
q is the design tier, i the impact, n the sample, and the kind with its r
the rigour judged within that kind: what each code means.
This claim: no standardized effect is recorded in observations/ for it yet, so no benchmark reading is possible.
q3 i? With proper control of distribution factors, intensities high enough for maximum discrimination of detail can be used without appreciable damage or discomfort to the eye. → C. E. Ferree and Gertrude Rand 1917
Evidence¶
C. E. Ferree and Gertrude Rand 1917¶
C. E. Ferree and Gertrude Rand. (1917). The Power of the Eye to Sustain Clear Seeing Under Different Conditions of Lighting. The Journal of Educational Psychology. https://doi.org/10.1037/h0072369
q3 · i? · causal · r2
Laboratory testing program comparing actual lighting installations in common use, with acuity-sustain records taken before and after reading tasks. The authors report that when distribution factors are controlled, the eye is "practically independent of intensity" across the ranges encountered in lighting work.
"our tests indicate that the eye, so far as the ranges that are apt to be encountered in the work of lighting are concerned, is practically independent of intensity"
Discussion¶
Related Claims¶
- Extremes of surface brightness in the field of vision are the most important causes of eye discomfort and loss of efficiency in contemporary lighting systems — a broader claim this one bears on
- Indirect systems and semi-indirect systems with high-density reflectors produced the best results for sustaining clear seeing among the artificial lighting systems tested — related
- Too much light is being used in ordinary work for the comfort and welfare of the eye with reflectors that introduce harmful brilliancies — related
- The loss of efficiency sustained by the eye in an unfavorable lighting situation is muscular, not retinal — related
- Normal sense organs possess surplus discriminative efficiency beyond ordinary practical demands — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
good-distribution-eye-independent-of-intensity |
title |
When light is well distributed and diffuse with no extremes of surface brightness, the eye is practically independent of illumination intensity within ordinary lighting ranges |
description |
When light is well distributed and diffuse with no extremes of surface brightness, the eye is practically independent of illumination intensity within ordinary lighting ranges |
status |
review |
evidence_strength |
moderate |
newest_evidence |
1917 |
generated |
by process:wiki-ingest on 2026-10-25 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — c-e-ferree-and-gertrude-rand-1917 |
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