Color Temperature Calculator

Frequently Asked Questions

Why use mireds instead of Kelvin for filter selection?

Equal mired steps produce equal perceived color shifts regardless of the starting temperature. A 100-mired shift looks the same whether you are going from 3,000 K to 3,300 K or from 5,500 K to 6,100 K, which is not true for raw Kelvin differences.

What does a positive mired shift mean?

The target is warmer (lower Kelvin) than the source. You need to add an amber or warming filter to shift light toward the target.

Can I stack gels to achieve a large mired shift?

Yes - mired values of stacked gels add together, so a half CTO plus a quarter CTO gives you about 97 mireds of total shift.

Does white balance in camera give the same result as a physical gel?

For raw shooting, camera white balance corrections are largely equivalent. For video or JPEG, gels on the light preserve the full dynamic range and avoid color noise that post-processing introduces.

Provided by AllCalculators.io
Free online calculators for everyday. No registration required.

Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

JavaScript is required to use the interactive calculator above. The questions and answers below remain readable without JavaScript.

How It Works

Color temperature describes the warmth or coolness of a light source in Kelvin (K). Candlelight sits around 1,800 K, tungsten lamps near 3,200 K, average daylight around 5,500 K, and overcast skies can reach 7,000 K or more. The higher the Kelvin value, the bluer the light; the lower, the warmer and more amber.

Because equal Kelvin steps do not produce equal perceived color shifts (the scale is non-linear), photographers use mireds (micro reciprocal degrees) instead: mireds = 1,000,000 / Kelvin. On the mired scale, equal steps do produce equal visible shifts, making it the standard for selecting color-correction gels and camera lens filters.

The mired shift = target mireds - source mireds. A positive shift means you need a warming (amber) filter such as an 81 series or CTO gel; a negative shift means a cooling (blue) filter such as an 82 series or CTB gel.

Use Cases

Understanding mired shifts is essential in many lighting situations:

Matching a strobe (5,500 K) to indoor tungsten ambient (3,200 K) on a film or video set

Choosing gel strength when mixing daylight windows with artificial sources

Warming a portrait slightly without completely color-grading in post

Converting between different color-correction filter families (Wratten, Lee, Rosco)

Understanding why a slight white-balance shift looks natural in one scene but extreme in another

Tips

Always note whether a filter is rated in mireds or Kelvin - they are different quantities and cannot be compared directly.

A full CTO gel adds roughly +130 mireds, shifting a 5,500 K source down to about 3,200 K; a half CTO adds about +65 mireds.

Warming the look means lowering Kelvin (raising mireds); cooling the look means raising Kelvin (lowering mireds).

Mired shift does not describe tint (green or magenta casts), which requires a separate correction axis in white-balance tools.

Shooting raw allows major white-balance corrections in post, but matching the source with gels at capture keeps colors cleaner and avoids noise amplification from heavy edits.

FAQ