2% milk?

The rule of thumb is that you thin your paint to the consistency of milk with 2% fat or 98% fat-free.  How do you judge that?  It does indeed take a certain knack that for me simply took a lot of experience to gain.  Even now, I'll sometimes add too much or too little thinner.  Things I look at to help me determine the paint consistency is to see how it flows off the toothpick that I use for mixing and to see how the paint flows down the side of the color cup. 

Andy 

To be honest, I never use the 'consistancy of milk routine.  I just mix my paint with a tooth pick. I shake it for a little bit, open it and mix it.  After a little bit of mixing I pull it out, if there is any paint globbed (like solid) on the pick I add thinner, and mix more, then shake, untill no more solid glob.  Then its the right consistancy for me.

Using the Mark I eyeball is a talent, and is best used after much practice. One of the best ways to learn is to actually get some 2% milk and seeing how it looks swirled in a glass and dripping off a toothpick.

Personally, the only time I get "real" precise is when I'm mixing colors. Otherwise I slop thinner into the color cup, and then stir in the paint. That can be any where from 50/50 to 80/20. Paints with lots of pigments (black, dark blue, red) can be thinned quite a bit, while paints with less pigments (white and yellow) require less thinning.

I still measure precisely with syringes, but as a retired lab rat, it's just an old habit—but it's a good way to learn.

The problem is that different paints, even of the same brand, may have different viscosities, which change slowly over time with gradual solvent loss. So I start by measuring fairly carefully an amount of thinner that I think is just too little. Then I look at it. If it looks like it needs more thinner, I add more. If it looks too thin, I add a little paint.

The suggestion to actually look at some 2% milk in your mixing container is excellent. And the bottom line is that it takes practice, just like everything else with an airbrush.

I use Tamiya acrylic paint almost exclusively and I mix it 3 parts paint to 1 part thinner and that works perfectly. But to get back to the milk thing, pour a little 2% milk into a clear glass. Now gently roll the milk in the glass to get some up the sides of the glass. Look closely at the area washed by the milk to see how much of the milk "stuck to" the sides and imagine your blue or green or grey leaving the same degree of transluscence on the side of the glass. That's what you're after.

Basically though, it comes down to experience and experiment. Once you've got the formula, you're all set. Keep 'fiddling' and you'll get it.

Rich

Ditto the method of actually observing 2% milk. That really made a huge difference for me in my airbrushing.

Helps to have some Oreos handy too......

I thought I was losing it. TWO% milk, not one or three. TWO.

cheers