Question

why did the British official put everything in black and white ???​

Answer 1

I think--it was Much easier to read than using white ink on white paper or black ink on black paper ...

Answer 2

Answer:

They introduced India to the rigid bureaucratic frame work, to rule a big country with a far bigger population. They started the Indian Civil Service drafting the best talent from Britain (later Indians too) & an effective police force. They gave a fine judiciary. Also provided a top notch Accounting service. The administrative & police services are still the skeletal frame-work of Indian nation. It is so efficacious that India sticks to them that the British provided; and why not? Population in Indian Empire was two thirds of the whole Empire. Please note that the British didn't have such things for their own people as they felt that they don't need one. 

All these require black 'Indian' ink on white paper (Black & White).