I've played around with how to paint my guns for infinity minis for a few years now and thought I'd share my process. I hope it either helps someone or you are able to offer some advice, so that I might improve.
All colours are Vallejo Model Color
Step 1 - Black
After some airbrushing and initial glazing of the armour, I've re-painted the weapon with black, this is a really important step and I've been guilty in the past of avoiding it.
Step 2 - Base Colour
For this step I make a mix of colours, I use Dark Grey, Neutral Grey with a dash of Blue Green. The Blue Green has a big impact so I've learned to not add too much of it. I use slightly more Dark Grey than Neutral Grey. As I'm not a fan of wet palettes (shock horror!), I add a drop of retarder medium and some water to thin the paint.
I block out the majority of the weapon, leaving the gaps and lines black - this really helps define the shape of the gun, especially when viewed on a tabletop and not zoomed in like in these photos. On some of my older minis I used to base coat all over with this colour, but that means the gun loses definition.
Step 3 - 1st Highlight
To the above mix, I add a drop of Light Grey and more water as I want this layer to be thinner and have less coverage.
Step 4 - 2nd Highlight
I add white to the above mix and a small touch of water, just to keep everything flowing smoothly. White is such a chalky colour, so it's important to be concerned with smoothness.
Step 5 - 3rd Highlight
Instead of adding white to the above mix, I now start with a drop of white and add a brush stroke of the above mix. This will be quite a transition, so it's important to thin the mix and only paint a small area.
I made quite a few mistakes when applying this layer this time, so it's really handy to have the previous mix to help make corrections. Accepting that mistakes happen. before the final edge highlight, I try to clean up any black bits that have become obscured... I think that this is key to having a "clean" paint job.
Step 6 - Black Clean Up
I used to have this idealised view of painting miniatures where I could paint and every stroke would be perfect and there would be zero mistakes, which is how I imagine life is for Angel. Eventually I woke up and realised that I could improve my paint jobs ten-fold by taking the time to correct the mishaps. With that done it's on to the final step.
Step 7 - Edge Highlight
I tend to use pure white for this, I both love and loathe this step. Love it, because it's so good at making whatever you are painting really pop out. Loathe it, because it's so frickin' hard, well it is for me as I have crazy shaky hands.
Now for the rest of the model!
I hope you've enjoyed this write up and that it is useful to someone somewhere. If you have any feedback at all, then please do let me know. I'm always looking to improve and feedback is valuable.
A quick showcase of previous paint jobs... you can really see the lack of black undercoat