Gloss and light scattering
Gloss is smoothness at a scale too small to see. Polish a patch of a matt wall and it reflects differently — the dirt is gone and the mark remains.
In detail
A surface looks glossy when it reflects light in one direction and matt when it scatters light in many, and the difference is roughness at a microscopic scale rather than anything about colour or cleanliness. This is why so much cleaning damage is visible without anything being obviously scratched. Rubbing a matt emulsion wall flattens its microscopic roughness in that spot, so the cleaned patch reflects more directly than the wall around it and reads as a shiny mark. The wool trade describes the same effect on a garment: heavy pressure with an iron makes the surface of a sweater shiny, and it is explicit that this is a burnishing of the fibre surface rather than a heat burn. Fine abrasion on a gloss surface does the opposite, adding roughness and producing haze — the swirl marks on car paint and the dulling of a plated tap are thousands of scratches too fine to see individually. Two practical rules come out of it. On any matt or satin surface, clean the whole panel rather than a spot. And light at a raking angle reveals what light from behind hides, which is why the glass trade warns that a scratch invisible under a grey sky is obvious in sun.
Why
- Agitation is explained by Gloss and light scattering
- Ironing is explained by Gloss and light scattering
- Vehicle clear coat is explained by Gloss and light scattering
- Optical brightener is explained by Gloss and light scattering
Sources for this page
Sources
The Woolmark Company · Trade or professional body
Relied on for: That heavy pressure makes the surface of a wool sweater shiny, which is a burnishing of the fibre surface rather than a heat burn. (states this directly)
Verification: a person has read the passage relied on.
Read on — The whole page: setting, moisture, pressure and scorching. Supports the claim as stated. Sprint 7 recorded that no ironing guidance could be attributed to the wool body because the page then read gave none. That was correct about that page and is now superseded: a dedicated ironing page exists and has been read.
Glass Technical Paper FB01-00: Proper Procedures for Cleaning Architectural Glass Products
National Glass Association (NGA) with the International Window Cleaning Association (IWCA), 2023 · Trade or professional body
Relied on for: That light scratches may be invisible under a grey sky and obvious when the sun is at a certain angle. (states this directly)
Verification: a person has read the passage relied on.
Read on — 'Routine Cleaning & Maintenance', including the pure-water method paragraph. Supports the claim as stated.
Last reviewed by a person on .