Prevent polygon fade-in

OS: Win10
PsychoPy version: 2022.2.4 Standard Standalone
What are you trying to achieve?:
I want a white Polygon to appear at full color without fading in.
Right now, the Polygon appears light grey before ramping(?) to full white.

What did you try to make it work?:
I isolated this to a super simple case where there’s nothing except a polygon appearing every trial.
The polygon is specified as RGB: [1,1,1]

Images and Patches have the same behavior - they ramp up to the specified colors.
I tried setting gamma ramps and changing some specific gamma settings, but this didn’t seem to help and gammaIsDefault() returned false before I messed with anything. I tried messing around with linearizations in the monitor center with no luck - don’t think this should matter anyways.

What can I do to make my stimuli appear as-specified immediately, without ramping in?

How long is this fade in, is it just a few frames or a substantial amount of the duration?

It’s somewhere between .3 and .7 seconds, so 40-100 frames.