Teensy 4.0 Static Image to maximize brightness

Is there a way with the smart matrix library to set a static image to the display without a refresh rate so the leds stay on, rather than “flicker” ? I’m currently using 2, P3 panels, and the lowest refresh rate i can go is about 3hz, which still isn’t very bright. I’m using a power supply that can delivery 5v and up to 10 amps, so I’m not limited on the wattage.

Thank for reading.

Absolutely not, neither with SmartMatrix, nor with the help of any other library.
The matrices are arranged in such a way that at each moment only a part of the pixels is lit - 1/4, 1/8 or even 1/32. If you stop scanning, you will only see part of the screen.

The brightness doesn’t depends on refresh rate at all.

Ideally the brightness wouldn’t depend on refresh rate, but it takes a minimum amount of time to shift out data to the panel for a row, and depending on the color depth, sometimes the data takes longer to shift out than the pixels need to be on. In that case, the panels can’t get to full brightness as they’re spending some amount of time with the LEDs off and waiting for new data per frame. Increase the refresh rate and that amount of off time increases, so the brightness decreases.

Of course the minimal period between refreshings can’t be shorter than the time required to shift a new data to the matrix.
If you respect this ratio - the brightness doesn’t depend on scan frequency.

If you lower the color depth (kRefreshDepth) this can increase the apparent brightness without changing the refresh rate. I would try kRefreshDepth in the <24 range if you care about brightness more than color accuracy.
You need a refresh rate higher than about 100 FPS to avoid flicker.

Also make sure you set the overall brightness to the max with matrix.setBrightness(255).

Some panels can only go to 254 without glitching.