Take three cups and add the dosai batter in all the three cups.
Keep one cup aside and this will be used as the white batter.
For the orange batter, grind tomato and red chilli into a fine puree.
Mix it with the second cup of the dosai batter. There should be no lumps. The batter should be smooth.
For the green batter, grind coriander leaves and green chillies with little water,
Add this into the third cup of batter.
Now keep all the three batter ready.