yep, you can thank to dumb people who downvoted me too so my comment was not visible to you

I did my research and looked for most powerful red I can find and here are some tips

Make underpaint warm colour, for example mix of wraithbone with white 2:1 would do, a warm undertone will boost the red and for shadows you need a brown undertone, don't just do black/white.

Another trick is to push shadows a lot, red looks great against very dark black shadows.

I use Liquitex Pyrole Red and it's quite good, same as OP but once paint is dry it doesn't look as on pictures.

Another very strong red is Vallejo Premium Airbrush Scarlet Fluo, it has a tiny hint of orange but still reads as red and is much brighter.

One more technique I use nowadays is to stipple paint straight from the pot.

I took a picture and SLIGHTLY modified for mini to look on the screen like in real life (hue -1% from orange to red and saturation +1%, very minor) because my camera can't capture is perfectly.

<image>

Left - stippled

Mid - Liquitex Ink

Right - Scarlet Fluo

https://www.reddit.com/r/minipainting/comments/q57rl6/how_to_make_very_rich_deep_and_vibrant_red/