Half Dome, No Color

Notes

Everything has to happen in one step

The sky and the rock are almost the same grey. There’s maybe one value between them, which means the entire mountain is separating from the background by the narrowest possible margin. Make that gap any smaller and the dome dissolves. Any larger and it turns into a cutout pasted on a backdrop.

The name oversells the geology. Nothing broke in half and rolled away – that half was never there. What happened is exfoliation: granite forms under pressure, the rock above it erodes off, and the release makes the granite shed in curved sheets like layers off an onion. Glaciers undercut one side and steepened it. The missing volume is closer to a fifth than a half.

Overcast is why this works. No sun means no cast shadow, no lit side, none of the contrast that usually does the modeling. What’s left is the rock’s own value differences – the vertical streaking down the face, the slabs where the surface has spalled off, the darker recesses. On a sunny day those get overwhelmed by shadow. On a grey day they’re all there is.

Five greys, no color anywhere. I tried more steps between the lightest and darkest and it went soft – with values this close together, adding one more just splits the difference and blurs the edge that was doing the work. Five holds. The sky is a single flat field and took no time at all, which is not something to bring up in front of the face.