Which gel matches a window to tungsten?

For a 5600 K window and 3200 K lamps: Full CTB (LEE 201) on the lamps lands 3 mired off, or 1/2 CTO plus 1/8 CTO (LEE 205 and 223) on the window lands 1 mired off. Meter works it out for your real lights.

Step by step

1. Point at the light you want everything to match and tap REF to pin it.
2. Point at the other light. The REFERENCE card shows REF, NOW and the difference in kelvin, mired and tint.
3. Read ADD TO THIS LIGHT: the CTO or CTB to clip on, at most two sheets, and what is left in mired.
4. Clip it on and read again. MATCH shows when the two are within 5 mired.

If that didn't work

To match to a color you know, hold REF and type a target from 2,000 to 10,000 K. The free gel calculator on this site does the same sum without a phone.

Go further

• The window is daylight and the lamps are tungstenGuide
• Gel calculatorFree tool

Last updated October 26, 2026