artefacts are little bit of greenier pieces/hue on the texture. You dont really prevent them you just reduce them. Its curse of outdated ways and tools. Since you are using the correct VTFEdit then it should be best it can.

In case you want, someone made reccomended settings on painters workshop so you can join back in for a bit since you used to be there.

Thank you. How do I know if my textures are artifacting or not, and how do I prevent it? I'm designing them in photoshop and using VTFEdit Reloaded to save my textures.

Oh nice, an interesting idea i havent actually seen. Good job.

However, dont use phoenix in promos. That map sucks for it as it makes the warpaint more orange tinted.
The yellow on the scattergun promo has actually better looking yellow imo but the current one isnt that bad either. I also noticed way too much green artefacts on the black, you should use VTFEdit Reloaded if you arent already.