---
title: "Direct light (Light Return): meaning in gemology"
description: "Direct light is light that reaches the viewer from 45° to 75° above the girdle plane. Our light map shows it in red."
url: https://digitalgemology.com/learn/glossary/direct-light
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

> Markdown copy of https://digitalgemology.com/learn/glossary/direct-light. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons.
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[Glossary](https://digitalgemology.com/learn/glossary) · Light performance

# Direct light (Light Return)

Also called direct, direct light (Light Return)

Direct light is light that reaches the viewer from 45° to 75° above the girdle plane. Our light map shows it in red.

## In more detail

This is the bright light from above, outside the zone of the viewer's head. A well-cut round in diamond returns most of its face-up area as direct light.

## How we measure it

The simulator's light map classes each face-up ray by the elevation its light came from. Rays from 45° to 75° count as direct.

## Related terms

- [Light Return](https://digitalgemology.com/learn/glossary/light-return): Light Return sorts each point of a face-up stone by the direction its light came from. Its four classes, direct, indirect, contrast and leakage, together cover the whole face-up stone.
- [Light map](https://digitalgemology.com/learn/glossary/light-map): A light map is a face-up picture of a cut stone, colored by the direction each point's light came from. Red is direct light, green is indirect light, blue is contrast, and a dark color is leakage.
- [Indirect light (Light Return)](https://digitalgemology.com/learn/glossary/indirect-light): Indirect light is light that reaches the viewer from below 45° above the girdle plane. Our light map shows it in green.
- [Contrast (Light Return)](https://digitalgemology.com/learn/glossary/contrast): Contrast is the part of a face-up stone whose light comes from 75° or higher above the girdle plane. This zone lies within 15° of the line of sight, where the viewer's head is.
- [Leakage](https://digitalgemology.com/learn/glossary/leakage): Leakage is light that enters a stone and leaves where the viewer cannot see it, mostly through the pavilion. Lower leakage is better.

## Learn more

- [3D Gemstone Simulator](https://digitalgemology.com/about/how-we-measure/simulator)
- [The bow-tie effect in diamonds: what it is](https://digitalgemology.com/learn/bow-tie/bow-tie-effect-in-diamonds)

[All 328 terms](https://digitalgemology.com/learn/glossary)