Tungsten Balance

A camera is balanced for one colour of light. Set that balance for household bulbs and the room looks normal, while every window in the shot goes deep blue.

The result is a picture carrying two temperatures at once. Inside is warm and safe, outside is cold and elsewhere, and the window becomes a line between them without anyone having to say so.

Balance for tungsten, around 3200K, and light the interior with bulbs near that colour. Daylight through a window arrives at roughly 5600K, so it lands blue by a wide margin.

Two sources are required. The whole effect is a comparison, so a room with only lamps has nothing to compare against and simply looks neutral. Put a window, a doorway or a screen in frame.

Exposure decides how hard it reads. Let the window sit two or three stops over the interior and the blue outside becomes the brightest thing in the picture.

Use it on interiors that look out, on night scenes with a streetlight or a screen, and on any scene where inside and outside mean different things.

Skip it in a windowless room. With no second colour of light in frame, the balance gives you nothing a warm grade could not.

A warm amber grade tints the whole frame, windows included. Tungsten balance leaves the interior looking neutral and sends only the daylight blue.

The test is the window. If the view outside is warm or neutral, the picture is graded. If it is blue while the lamps read normal, the camera is balanced for tungsten.

Stanley Kubrick lights the interiors of Eyes Wide Shut (1999) with warm practicals and coloured Christmas lights and lets the street outside read cold, so almost every room carries two temperatures at once. The Shining (1980) works from the same idea, with the hotel warm from its own fixtures against the blue of the snow.

One light source comes back and the effect disappears. Name both: warm lamps inside, daylight through a window, and say the window goes blue.

The other failure is a window blown to flat white with no colour in it. Ask for the daylight to hold its blue rather than clip, and say the interior reads neutral.