Sepia · Satheeshan Thiyagaraja

Three dials, one result. Temperature declares what light you are claiming to shoot under, and the two shifts nudge the outcome off that declaration.

The part that trips almost everyone: a higher Kelvin number produces a warmer picture, not a cooler one. The number describes the light, not the output. Tell the camera the light is 8000K — very blue — and it compensates by adding amber, so the file comes out golden.

That is why Temperature and Shift A/B are really one amber–blue axis in two different units, and why a warm Kelvin paired with a B shift is not a contradiction. It is a broad warm base with part of it deliberately pulled back. It buys precision the Kelvin dial cannot give on its own: a single 100K step is worth about 15 mired down at 2500K but only about 1 mired up at 9900K, so the shift is the finer control at the warm end and the coarser one at the cool end.

Shift G/M is the second axis, and Kelvin never reaches it. It is the tint control: G cancels the green cast of fluorescent light and open shade, M goes the other way.