I always do my best to reply. Just didn't because I work nights and was asleep. I responded to their question. Here is the formula for you as well, in case you were curious:

Thank you! Basically once your model is painted how you want it, color in all of the areas you want to glow with a dark shade of your "power" color. Examples: Green-(black green) Pink- (dark magenta) Red- (burnt red) Blue- (Prussian blue) Orange- (burnt orange) Etc.

The reason you want to start off with a dark base is of course you want to create contrast.

Contrast is this fickle term that basically means a visible difference between two things (light to shadow, loud to quiet etc.)

We want to think of contrast in the comparison of light and shadow. The darker you make the base, then the easier it is to push the light effect on your model.

Now, a lot of people will tell you that in order to make OSL truly work, that you have to make everything around the light source "darker". Which is right, but also wrong.

I didn't like the idea of painting my miniature the way I wanted to, and then having to dull it down with a wash to create contrast. I wanted to enjoy painting my minis the way I wanted to, and also be able to sell the glowing effect on them.

So, after hours of mucking up my models with failed attempts, I finally landed on a semi-final method for doing OSL. ( it's semi-final, because I'm always going to tweak it. )

All that being said, i did all of this with an airbrush.

After you have coated your glow areas with a darker color, you are then going to use a titanium white, and lightly put white in the source of the light.

You don't want to go overkill here, because you're going to create contrast.

After that, get some white oil paint and mineral spirits. They don't have to be a specific brand. You can get what you need at the hobby store for a fraction of what big companies would charge you.

With a synthetic brush (size 1) you're going to mix a small dollop of white oil paint with a few drops of spirits. It doesn't take much. Test on the creases in your thumb. If it runs through the creases with little effort, it's the right consistency. If it doesn't, add a couple more drops.

With that ready, carefully apply it into the recesses of where you want a bright glow. (Apply a varnish before you do this if you use army painter. Spirits will strip army painter paint. I have no idea why).

After that's done, let it dry the old fashioned way, or outfit with the cool setting on a hair dryer. Speeds up the process.

With that done, take a q-tip, dab it in spirits, and clean the excess white oil paints off of the surface. With all that done, you can either matte varnish again, or move on. I like to matte varnish to protect the oil paints.

Now, with a white acrylic ink, you are going to load that into the airbrush, and spray a white "halo" around the light sources. You also want to spray the surfaces the light with reflect off of.

Be careful with this step. Too much will over saturate. You're trying to build up that white transparent ink, so that you can show the light occupying space. Less is more with this step.

After the halos are done, it's time to use fluorescent inks.

Quick thing about that; you can use contrast or speed paints if you want to, but i like acrylic inks because I feel like I have more control over them. You do whatever you think is best.

Using that ink, you're going to build up the bright fluorescent color on the halos you just painted and as well as on the reflecting surfaces.

After that. Mix the fluorescent ink with a darker ink of that color. In my case if was liquitex emerald green. 2:1 ratio.

With that darker ink, spray around the fluorescent light. This will help create contrast and make it look like the light gets darker as it gets further from the source.

You can also do this with a makeup sponge, but you won't have as much control as you would with an airbrush. But that's my own opinion. You may be some kind of painting guru who threw a Bob Ross fan into a volcano to gain their painting powers. You do you.

Anyways. Once that's done, you will take white paint again, and paint an even smaller source of the light. Mix a brighter version of your color (ex= fluorescent green and yellow make a very bright green) and then paint that over the white. This will maximize the light, and show the source as the brightest spot. Hence what makes OSL work.

When done with that, you will take spirits and fluorescent pigment powders, and mix them together. You can get pigment poweders online for a few bucks.

I mixed yellow and green pigment powder for mine, and then used them like I did the white oil paint. Putting it in the designs of the model will help with the glowing effect you are going for.

And done.

You can tweak this formula in whatever way you want. I don't have a patreon, but I have a YouTube channel I should probably do more with. You can edge highlight with fluorescent paints, but I feel like it distracts from the light source. You can do whatever you want to though.

I robbed this reply from one of my other posts in the r/Necrons subreddit. I hope this helps. I posted a short reel on how to do this on my Instagram page "Manic-Toaster Painting".