Stacking colors darkest-on-top makes the eye read a transparent veil even though every layer is opaque

An Albers Preliminary-Course exercise demonstrated that transparency is a perceptual construction, not a physical property of the paint. When the darkest color sits on top and progressively lighter values run below in a stacked pairing, the eye reads the arrangement as a transparent veil resting on the surface beneath — even though every band is fully opaque. In the source’s Bormann study, each square pairing shows a progression from opaque to transparent, and the effect ‘only makes sense if one imagines an actual painting’ where a lighter hue is painted over a darker plane. The lesson — that material and spatial qualities of color are constructed by the viewer — is directly useful in shader work: sequencing opaque passes by value can suggest translucent materials without any real alpha compositing.

Examples

Heinrich Bormann’s 1931 tint study: paired swatches with the darker on top read as transparent-over-opaque. In GLSL: a dark brownish orange layered over a lighter warm tone reads as amber glass with no alpha blending.

Assessment

Using only fully opaque fills, produce an image that reads as containing a transparent overlay, and explain which value/color ordering creates the illusion.