Perception of a Black Room Seen Through a Veiling Luminance.

Alan Gilchrist,Michael S Langer

doi:10.1177/2041669520973698

Alan Gilchrist, Michael S Langer

Open Access

https://doi.org/10.1177/2041669520973698

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Abstract

When a black room (a room painted black and filled with objects painted black) is viewed through a veiling luminance, how does it appear? Prior work on black rooms and white rooms suggests the room will appear white because mutual illumination in the high-reflectance white room lowers image contrast, and the veil also lowers image contrast. Other work reporting high lightness constancy for three-dimensional scenes viewed through a veil suggests the veil will not make the room appear lighter. Because mutual illumination also modifies the pattern of luminance gradients across the room while the veil does not, we were able to tease apart local luminance gradients from overall luminance contrast by presenting observers with a black room viewed through a veiling luminance. The room appeared white, and no veil was perceived. This suggests that lightness judgments in a room of one reflectance depend on overall luminance contrast only.

Highlights

When a black room is viewed through a veiling luminance, how does it appear? Prior work on black rooms and white rooms suggests the room will appear white because mutual illumination in the high-reflectance white room lowers image contrast, and the veil lowers image contrast
In the work reported here, we addressed a very simple question: Would a black room seen through a veiling luminance appear as a white room in plain view or as a room darker in color than white, behind a veiling luminance? Two prior lines of work suggest opposite answers to this question
A black room viewed through a veiling luminance appears to be a white room

Summary

Introduction

When a black room (a room painted black and filled with objects painted black) is viewed through a veiling luminance, how does it appear? Prior work on black rooms and white rooms suggests the room will appear white because mutual illumination in the high-reflectance white room lowers image contrast, and the veil lowers image contrast. Other work reporting high lightness constancy for three-dimensional scenes viewed through a veil suggests the veil will not make the room appear lighter. The room appeared white, and no veil was perceived This suggests that lightness judgments in a room of one reflectance depend on overall luminance contrast only. In the work reported here, we addressed a very simple question: Would a black room seen through a veiling luminance appear as a white room in plain view or as a room darker in color than white, behind a veiling luminance? Would lightness be veridical without the possibility of comparing different shades of gray? And, apart from absolute luminance, would an all-black world appear different from an all-white world? Intuitively, the answer was yes, but what information could be used to make the distinction?

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