Reading the waveform and vectorscope, and what the skin tone line is for

Your eyes adapt. Stare at a green-tinted shot for a minute and it starts to look neutral. Scopes do not adapt, which is why colourists trust them over the monitor. You only need two.

Waveform: how bright, and where

The waveform is your image read left to right. Each column of the picture is plotted straight above its position, with brightness as height: 0 at the bottom is black, 100 at the top is white.

• Log footage sits in a band in the middle. Nothing reaches the floor or the ceiling.
• A finished grade stretches out: shadows come down near the bottom without sitting flat on it, and highlights rise without flattening against the top.
• A flat line at the top or bottom means detail has been clipped and is gone.

As a starting point for a normally lit face in Rec.709, skin highlights tend to fall somewhere between 55 and 70. Darker skin sits lower and that is correct. Do not push every face to the same number.

Vectorscope: which colour, and how much

The vectorscope ignores brightness. It plots only colour: the angle around the circle is hue and the distance from the centre is saturation. A black and white image is a single dot in the middle.

The six boxes are the targets for red, magenta, blue, cyan, green and yellow. If the whole trace is pulled toward one of them, the shot has a cast in that direction.

The skin tone line

There is a line running from the centre up between red and yellow. Human skin of every ethnicity falls on or near it, because what you are seeing under the surface is blood. Lighter and darker skin differ in how far out they sit and how bright they are, much less in their angle.

To use it:

1. Draw a small window on a patch of evenly lit skin: forehead or cheek.
2. Look at the vectorscope. You get a short streak.
3. If the streak leans toward yellow, skin reads green or sickly. Toward red, it reads flushed or magenta.
4. Nudge it back with a skin-only adjustment, not with the white balance of the whole shot.

It is a guide, not a law. Sunset light, neon and firelight are supposed to pull skin off the line. The line tells you where neutral is, so that leaving it is a choice.

Try it

Every wipe on this site has a live waveform and vectorscope computed from the frame you are looking at. Drag the wipe in the demo and watch the band of log footage open up, and the skin streak settle onto the line.

Common questions