Answer

The spectre paint should be available in shop under the "special offers" tab. Please check in "special offers" tab. If it's not available there then, can you please take a screenshot of it and upload in here?

Answer
The only ways to receive the spectrum paint was either by opening containers or by buying the special bundle. The animated paint wasn't sold separately.
Customer support service by UserEcho
The only ways to receive the spectrum paint was either by opening containers or by buying the special bundle. The animated paint wasn't sold separately.