Fix a green or magenta light

With a reference pinned, the REF card adds a green or magenta suggestion when the two lights differ in tint: 1/4, 1/2 or Full PLUSGREEN or MINUSGREEN. It is always marked approximate.

Step by step

1. Pin the light to match with REF.
2. Point at the light that looks green or magenta.
3. Read the line under the CTO or CTB answer, for example plus 1/2 MINUSGREEN, approximate.
4. Clip it on, then read again and check the tint.

If that didn't work

Meter suggests nothing for a very small green or magenta shift. The suggestion is worked out from the tint at that light's own temperature, so treat it as a first try and judge the result on the camera.

Go further

• Why does my footage look green?Guide
• CTO, CTB and green gels in one chartChart

Last updated November 2, 2026