My paint is... Changing color?

[swagster2000]

Well, so, I’m experiencing something.
So I got this AMIG Sinai Grey Acrylic color

And it’s really really weird.
Out of the bottle it’s this color, which seems obvious, like, it’s the same color as in the bottle, duh.

And while it’s not the color I was looking for, I was looking for, well, the actual grey found on the Merkava Mark 4 for example, I tried painting a tank with it, and, somehow, for some reason, when I applied it via airbrush, it did come out as the grey I was looking for:

This does not look like the color in the bottle. But it is. It’s the same paint, I didn’t mix or add anything to it. It just, came out looking the perfect grey I was looking for. So I did another tank with it, the Merkava mark 4, and again, it came out as the perfect grey I needed:

Great, right?
But now I’ve painted my Sho’t Kal Gimel I’m working on, which needs the same Sinai Grey. I did it like I always did, thinking once again the paint will come out as this grey, but for some reason, this time it came out the color that the paint actually is, in the bottle!

It’s a subtle difference, but you can see it in here, with the Magach and Merkava in the background, they’re much more grey, while the sho’t came out closer to desert tan:

And, I’m just so confused. Why did the paint change all of a sudden? I know this is a weird question, but why is it accurate to the paint in the bottle and outside of it now all of a sudden, when in the last two times I used it in my airbrush, it came out a sinai grey?
I didn’t do anything different. I use my airbrush to apply it in the same way and layers, over a black primer base with white primer preshading (which I considered to be the culprits in changing the color, but no, it can’t be, I did the same black basing with white preshading in the Merkava and magach)

I know this is way out there, but can anyone figure out why my paint changed all of a sudden on this tank? It’s the same paint bottle used in all 3 tanks, with the same airbrush, same base coat, same technique, but all of a sudden it’s not the sinai grey of the magach and merkava. What the hell is going on here?
Here’s a more direct side by side comparison of the colors

Would really appreciate any help if anyone knows! I have a lot more tanks to pay with Sinai Grey and I’d like to be able to get the same color with all of them!

[Uncle-Heavy]

Same technique with the airbrush?
Same air pressure, same airbrush?
Same weather/humidity?
Did you stir the paint or shake the bottle thoroughly?

[swagster2000]

-Yes, certaintly
-I think I might have painted at 20 PSI rather than 15, could that have made that much of a difference?
-Yes, same, maybe a tiny bit colder, but not my much
-Yes, I always shake the bottles thoroughly for like 20 seconds before each use, even when I top off the paint reservoir, I shake it prior

[Biggles50]

I’ve read that about real Sinai Gray paint…it’s sort of a chameleon color. Sometimes it looks grayish; sometimes greenish; and sometimes sandy- brownish. I think it has something to do with the time of day ie; position of the sun.

[Dioramartin]

Shaken, not stirred? All other possibilities seem to have been eliminated, so was it Sherlock that said when that happens, the only remaining solution must be true no matter how far-fetched it seems. I always stir thoroughly with a toothpick for at least 30 seconds every time no matter what kind of paint it is.

[swagster2000]

Alright, well I tried this, went and stirred the bottle like hell with a toothpick for like a minute. When I took the toothpick out I didn’t see anything odd on it, no residue or clumping, nor did the paint or color inside the bottle change, also did a few test drops on paper, it was the same as always
But anyway, I did a test with my airbrush, and, nothing changed. It’s came out as the same desert tan-ish color, rather than the grey color I got on the magach and merkava
So, probably not related to stirring rather than shaking…
Super weird…

[varanusk]

I guess it must be related to shaken. Perhaps it was not well mixed when painting the first tank and the yellow pigment stayed at the bottom

[Biggles50]

I found this recipe somewhere on line for one variation of Sinai Gray: 50/50 mix of Tamiya Medium Gray (XF20), and Tamiya Buff (XF57). Like I said, this is just one variation of this color - other modelers may have differing opinions.

[phil2015]

I had a similar experience with a Tamiya paint and concluded there was just more pigment in the mix the second time around (as the amount of carrier in the bottle decreased). I think I’m diligent about mixing but I always have a kind of pigment layer at the bottom of a Tamiya paint bottle. I’m not sure that makes sense for a dropper bottle though…..

[swagster2000]

Well, seems like from now on I’ll have to mix my paint with some grey to achieve the same sinai grey on my magach and merkava….
Oh man, I hope I can get it as close to identical as possible…

[Edro]

Some paints will separate out significantly. If the paint isn’t thoroughly mixed, every time from when you first open the paint, you can end up with what you are experiencing. BTW, I think you got great results with what you had.

Edro

[Damraska]

I think Ralph at the factory put the wrong label on the bottle. That looks way too much like earlier IDF sand colors.