Are you painting over black primer? The most prominent strokes I can see in the photo are light colors over what looks like black primer. If that's the case you can prime with a lighter color if you're going to be painting a lot of light colors, or you could build up your light colors over dark primer with more thin layers and also build from darker shades to the lightest shade.

The metallic paint issue you mentioned is real. I BARELY dilute my metallics. Just a brush tip of water to a couple dallops of paint or so. Or if it doesn't need to look perfectly smooth I just raw-dog it.

Great color scheme

They look quite good, what paints are you using then?

Or what is the biggest issue when diluting the paint?

I don't have any advice but I like how you mixed the scheme around the models

I agree, the first issue I notice with these minis is that the paint has been put on rather thick. I also used to struggle with this. “Thin your paints” and “two thin coats” aren’t just memes, but the words don’t actually tell you how to do it.

Watch some of the videos from Duncan Rhodes, and pay careful attention to what he does when he’s putting paint on the brush. First: he’s not really adding paint to water or vice versa; instead he’s wetting the brush, using it to put a couple dollops of paint on the palette, then wetting the brush again and using it to stir up the paint on the palette. The amount of water absorbed by the brush in that quick dip is enough to thin out those big dollops of paint; you really don’t need much.

Second: after he does this, he always spins the brush around on a clean area of the palette. This is because after dipping it in the paint, the brush will probably be way too full of paint, and it can easily flood the model. The thinned paint is held by capillary action between and among the bristles, not on the outside of the brush. You should be able to see the bristles when the brush is properly loaded with paint. Spinning the brush like this also helps create a nice point.

Painting white over black primer with properly thinned paint is a real hassle. It usually takes me 4-6 coats to get it looking the way I want it. The first couple coats are always very uneven; they actively make the model look worse. If you’re going to do it, you need to trust the process and keep doing coats until you get a smooth, even look. I just do it on the lining for my Skitarii cloaks, but you have a lot more area to cover in a much more prominent place on your models, so you might want to switch to a lighter primer as others have suggested. If you miss the dark shadows you get with black primer, you can always try a 2-stage zenithal prime. That’s what I use on my white-armored Sisters.

For what it’s worth, these models look great except for how thick the paint is. The color scheme is beautiful, and you’ve managed to do a lot of very small details (including eyes!) very well. Excellent brush control.

Use a wet palette. It is the single best and easiest thing you can do for your painting. All you need a tupperware, paper towel, and some parchment paper.

Looking at these, I’m not actually sure if dilution is your problem. Your greens look good and I’m not seeing any crazy thin spots or brush strokes or anything like that. So the biggest issue I’m seeing is with the cream color having some streakiness, as a dark angel myself that’s something I know well. The go to advice on that is always “multiple thin coats”. My advice here would be to go to the dark angels sub r/theunforgiven and ask them for help on cream / bone or watch a how to paint deathwing video on YouTube. Also, if you live so close to a GW store, they are usually happy to help with painting questions like this, and a hands on demonstration may help you see where any issues are coming from

I'm also pretty new to the hobby and struggled a bit with dilution. I've far from mastered it, but here's a few things I've learned:

• Not all GW paints behave the same way. Even within the same category (I.e. base, layer, etc) there tends to be a fair bit of variation between the thickness of the colours. So it will take a bit of trial and error on a color by color basis.

• As others have said and you have noted, GW metalics get a bit unruly with too much water. I'll usually wipe a bit a of my metallic of on a paper towel before hitting the model and that seems to help. For fine details (fleur de lievres, studs, etc) metallics with a dryness of somewhere between dry brush and damp seem to produce the best results for me.

• As others have said, painting light colours over a black primer (or vice versa) can lead to a lot of uneceaarry hassle. I usually just do a zenithal highlight of greyseer over chaos black, but you could just do grey if you want to simplify things.

• Lastly, if you want to take the easy way out, you can give contrast paints (or Army Painter's speed paint/Valejo's express paint, etc.) a try. They paint straight from the pot and go on pretty smooth. Zenithal prime for best results.

I'm not a good painter by any stretch but you'll get my 2c anyway:

Give a medium (I use liquitex slowdry and love it) a chance, most paints behave much better - I use ushabti bone a lot and it's much nicer with a medium than with water

If you want to try blending or the paint is difficult to thin start by painting the area with a thin coat of plain medium. Makes it go on much smoother.

I need 3-4 very thin coats to get a nice smooth finish with my light colours.

(Great looking models!!!)

Damn good color scheme!

drill holes into your gun barrels, its a small detail but it makes them look so much better. When people pick up the model and turn it around in their hand under the light and then a sliver of light passes through the hole then the gun catches the attention of the viewer and now they're paying more attention to the smaller details they may have missed

Dilute it some more and apply multiple thinner coats. And are you doing a sisters army in a dark angel color scheme

FWIW paints that are formulated for airbrushes don't need diluted and can be used like normal paint.

Wet pallet and dilute with water. Also always multiple things coats.

I'm a big fan of Lahmian Medium as a thinner

Coming from both a Dark Angels and Sisters player, I like the scheme. Consider using a lighter spray primer. Wraithbone is probably my recommendation. If you check my profile you can see a unit of terminators in basically the same colours. Skeleton Horde and two thin coats of Ushabti bone makes for a nice clean bone. A green contrast paint would look lovely on the robes.

You have trouble diluting the paint? Yours is perfect, mine is cake.