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.

通过遮盖的亮度查看黑色房间（漆成黑色并填充有漆成黑色的物体的房间）时，它的外观如何？之前在黑室和白室中进行的工作表明，该室将显示为白色，因为高反射率白室中的相互照明会降低图像对比度，而面纱也会降低图像对比度。其他作品报道了通过面纱观看的三维场景的高亮度恒定性，这表明该面纱不会使房间显得更明亮。由于相互照明还可以修改整个房间的亮度梯度模式，而面纱则不会，因此我们能够通过向观察者提供一个通过纱幕亮度观察到的黑房间，从而从整体亮度对比中找出局部亮度梯度。房间看起来是白色的，没有面纱。