Racist or just the meaning of the word "Black" ?

Was having this random thought ...

Weeks ago , I went back to school for the farewell party gathering back at school, and representative for my course , Naresh went up for a speech and as usual we asked him to move infront of the projector , so that we can see him ! LOL ! Yes, he is Indian ! A great man though ! He is so used to us making fun of him that he can laugh and talk to us. Back in class, we used to off the light and shouted " Naresh , where are you ! " Those were the times haha !

So the question is, are we racist ? Or it's just the perception of the word black?

From young, parents tell us : Ehh Son, Your School Shoe BLACK already ! Go and Wash !
From young, parents tell us : Ehh Son, On the lights , it's very dark , it's bad for your eyesight when using the computer.

The meaning of black itself got a problem, and I believe as much as we make fun of Naresh, he know we are not racist towards him ( I hope ) , in fact most of us treat him as a good friend ! This kind of joke will sure be continued because of the meaning of Black ! So are we really racist if we only make jokes of them but did not look at them differently from other human beings?