Spectral transition guide

Help

Short answers to what goes wrong most often.

The frame says the effect needs WebGL

Spectral transition draws with WebGL 2 and needs the graphics card to store decimal numbers in its pictures, and this browser does not offer that. Turn on the browser's graphics acceleration, update it, or try another current browser. See float precision.

Tapping the picture does nothing

A tap during a run is ignored, so a run is never cut in half. Wait for it to finish, or press Replay, which always starts again at once. A run also only starts from a tap with the main mouse button or a finger.

The change goes the wrong way

After each finished run the direction flips, so the pictures swap turns: A into B, then B into A. Tap or press Replay once more to go the other way. Reset does not change the direction.

I cannot see the layers part

Raise Band stagger: near 0 every layer changes at once and the run looks like a plain crossfade. Two pictures with very different shapes also show the effect more clearly than two alike ones.

The Fourier method looks grainy partway through

Partway through a run, the Fourier method mixes the waves of both pictures, which leaves a fine woven texture over the frame until the run settles. The first and last frames are the pictures themselves. Set Method to pyramid for a smoother middle.

My picture looks stretched

The frame takes the shape of picture A, and picture B is stretched to that shape. Crop both pictures to the same shape first. Replacing A changes the frame's shape; replacing B does not.

My picture looks a little soft

The layers are built from a copy of each picture 1024 pixels on its long side, lightly smoothed, so a larger photo loses its finest detail. See downsampling.

My picture did not change

A file the browser cannot open as an image is skipped without a message. Try a JPEG, PNG or WebP copy of it. See JPEG, PNG and WebP.

It is slow, or the page struggles with a big photo

The pictures go to the graphics card at their full size before the smaller copies are made, so a very large photo takes more memory without adding detail. Use a smaller copy on a phone or an older computer. A larger frame also costs more on every step of a run.

Record video did nothing

The line under the buttons says why: some browsers cannot record a canvas, or offer no video format the page can use. Try a current Chrome, Edge or Firefox.

Where do my pictures go?

Nowhere. They are opened in your browser and drawn on your graphics card. Nothing is uploaded. The pictures you add stay on this device, in this browser, so the other lab tools can open them too; × on a picture removes it.

Are there keyboard shortcuts?

The tool has none of its own. Anywhere in the lab, Ctrl K, or Cmd K on a Mac, opens the list of all tools.

On a phone

It works with a finger: tap the picture to start a run. The controls sit in a bar at the bottom of the screen; tap the bar to open them.