Backdrops

What it does

Any still from your library can sit behind the whole programme instead of a flat brand colour.

You do not set the dimming. The renderer measures the image where the text will actually land and darkens it until the contrast is enough to read.

The standard behind it

• Dimming is measured against the region the captions occupy, not the whole frame. A photograph that is bright in one corner and dark elsewhere would otherwise be dimmed to almost nothing to protect a region the text never touches.
• The image is never washed out completely and never left undimmed. Both ends are bounded, because "legible" stops meaning anything if the picture is gone.

When to use it

Reach for a backdrop when the programme would otherwise sit on a flat brand colour — a talking-head or panel episode where the space behind the speakers is empty. A photograph of the location, the product or the subject gives the frame a sense of place without adding a scene or changing the timeline.

You choose the picture; the renderer chooses the dimming. A bright photograph is darkened further and a dark one barely at all, only as far as the captions over it need, so the same brand can use a sunlit exterior on one episode and a dim studio on the next without anyone adjusting a slider.

A backdrop sits behind everything and stays put. If the photograph should be the shot itself, cut it into the programme as a scene and give it motion on stills. If the image you want does not exist yet, describe it to generated pictures; what comes back is an ordinary library still, usable as a backdrop like anything you uploaded.