As Old as I Wanna Be

I wanted my knight to project that it was old — neglected, cursed with Nurgle's decay, and slowly succumbing to Grandfather's entropy.

The very sharp eyed among you may have noticed that the shot of my primed knight was ... rough, shall we say. Literally rough — I'd applied fine-grain sand to edges and other locations before priming, to ensure I had some raw texture to work with down the line.

Next step: The rust undercoat. First, I hit everything with a silver — I'm so tired of working with ceramite colors, I can't even explain with words — and then I added the rust colors.

Games Workshop's Knight Valiant, with a base made with cork and the scenic base from Forge World's Perturabo model.
Fine-grain sand has been liberally applied to the Knight Valiant.

To create the initial illusion of rust — it won't be the final, there's plenty more to do — I used Golden Hi-flow acrylics with an airbrush. I laid down a base of Sepia, then overlaid with Transparent Iron Red Oxide. There's a reason I'm laying down the rust effect first: it's because I'm going to create a mask, so when I apply my primary color, teal, I'll remove the mask and get a nice rust effect.
So what mask shall I use? Masking fluid? Tape? My fingers?

Nope.

Salt.

Well, salt and water.

Here's how it works: After the paint is dry, I use an old brush to dampen the sections I want to show through the final color. I then apply liberal amounts of large-grained salt — why, hello kosher salt, you're used for more than ice cream and delicious marinades — to the wetted sections. (Some tutorials suggest using hair spray, which seems like a giant pain in the lower back.) Most of the grains stick to the water well enough that they can resist even moderate blasts of air from my airbrush.

You go through a lot of salt this way. I tried to reuse old crystals. ...
In addition to the above bits, this picture features a loyalist Rhino box.

Once I was happy with the salt — yes, I did two passes, I'm aware of how absurd that is — I broke out the teal.

I love teal. It's one of my favorite colors — vibrant, yet nonconfrontational; bright, but somehow in the middle of the hue
structure and therefore able to be both highlighted and shaded; and it makes oranges pop. Use more teal.

Then I took a large brush, wetted it, and began wiping away the salt crystals. They (literally!) melt before the water, and leave behind areas of the underlying paint — in this case, mostly rust.

Sorry about the picture quality. For some reason, I just couldn't get a decent shot
of this effect — this is what you get, I guess.

You'll note there's not a perfect 1:1 between the sandy areas and the rust. I'm going to go back in and add a second later of above-paint rust and corrosion, targeting the sandy areas, but it'll have a different texture (thanks to GW's Typhus Corrosion). It'll also have a different color profile — while the existing rust splotches will tend toward orange, the other ones will tend toward green.

But before I do that, I'll go in and add some highlights — this is awfully monochromatic right now, and it could use some orangey splashes — and then we'll build up to the final crust. After that: OSL green lights.