# Concrete, and what it does with light
Author: Hana Sato
Author URL: https://demofolio.superblog.click/author/hana-sato/
Published: 2026-08-15
Category: Materials
Category URL: https://demofolio.superblog.click/category/materials/
Meta Title: Concrete, and what it does with light · Folio
Meta Description: Three buildings, one material, three completely different rooms. On board-marked, polished and pigmented concrete.
Tags: concrete, light, materials
Tag URLs: concrete (https://demofolio.superblog.click/tag/concrete/), light (https://demofolio.superblog.click/tag/light/), materials (https://demofolio.superblog.click/tag/materials/)
URL: https://demofolio.superblog.click/concrete-and-what-it-does-with-light/

![Light falling across a concrete wall](https://images.unsplash.com/photo-1630147278961-cf69d2c94ace?ixid=M3w3OTAzOTJ8MHwxfHNlYXJjaHw1fHxjb25jcmV0ZSUyMHdhbGwlMjBsaWdodCUyMHNoYWRvdyUyMGFyY2hpdGVjdHVyZXxlbnwxfDB8fHwxNzg4NjM0NzIzfDA&ixlib=rb-4.1.0&w=1600&q=80&auto=format&fit=crop)

Concrete gets called cold by people who have only seen it in car parks. In a room it does something to light that no other material does: it holds it.

## Board-marked

Cast against rough timber, so the grain prints into the surface. Raking light picks out every board. It looks like a wall that remembers being built.

## Polished

Ground back until the aggregate shows, then sealed. A floor that reflects the window in a soft way, like water at dusk.

## Pigmented

Iron oxide in the mix, a few percent, and the whole building goes the colour of the local earth. The chapel in the third photograph is the same colour as the field it sits in.

### The trick

Concrete is only as good as its formwork and its curing. Both are slow and both are boring, which is why most concrete is bad, and why good concrete is worth a whole post.


---
This blog is powered by Superblog. Visit https://superblog.ai to know more.
---