Hey Pritha,

Yes, you can go in exam hall with a black and white admit card. since, It is nowhere mentioned that you have to take a coloured or black & white print out of the CMAT Admit Card. If you are taking black and white print make sure your details and images are clearly visible on the admit card in order to avoid problems during verification at the exam center. Although, it's always advised to carry coloured admit card, this will make your verification easy.

Hope this helps!