Karras sigmas

Spaces the sampler's noise levels using the Karras schedule instead of the default one.

Often sharper at low step counts

The schedule decides how much noise comes off at each step rather than how many steps there are. Karras spends more of them at the low-noise end, which often sharpens the result at low step counts and matters less as the count rises.Some models are trained expecting it and some are not, and the panel reads the model's suggested schedulers to say which.The horde's own default is off, and this form starts it on.
Sampling · Interactive explorer Karras sigmas
The same picture rendered at Off
Karras Off
The same picture rendered at On
Karras On
The same picture both ways 512 × 512

The plain schedule at 10 steps, with little room left to settle the detail.The same 10 steps, redistributed so that more of them land near the end.

Fetching the example images.

Both settings together, side by side
Steps, top to bottom. The plain schedule, then the Karras one.
Steps down × Karras sigmas across Karras Off Karras On
Steps 6
Steps 10
Steps 16
Steps 30

Steps, top to bottom. The plain schedule, then the Karras one.

Pick any picture to see it larger. Arrow keys move between them.