When you open the m2 with m2modder and then press p (particles) you see all particles the m2 uses. Each particle has a number. If you press c (change colors) now, you can put in a number of a particle. For example the Particle with number 1 (1 is not always the first in list, there can also be 0). If you put in 1 and then press enter m2modder will show you 3 Hexadecimals. Start, Middle and End color. the first to digits is the opacity so just leave them as they are. You can change the other hexadecimal colors as you like. Just take Photoshop or something to look them up. I hope you understood everything. It looks like this for example:
Start Color: ffff0000 Middle Color: 00ff0000 End Color: a5ffffff
So the first 2 digits are opacity and the 6 after that describe the color. ff0000 is a red tone for example but I think you should know that
