So, what exactly is eyelash tint??

I was going to ask about a good mascara since I have pretty short mascara and Asians tend to have very straight eye lashes rather than curly... but then i came across eyelash tint?? So what exactly does it do, just coloring?? or does it work like mascara (lengthens & shapes)?? I'm looking to find something that could give me fuller, longer, and curl eye lashes... any recommendations??