Make text detect background colour and change colour due to this

Before I commence my design I was wondering if it is possible to get text in p's to 'detect' when the background-image colour is black rather than white and then the text would change to white when against the black background?

I have not started any code and would just like to know if this is possible before I start my design process? Possibly using one of the new CSS blending modes?

My plan is to use a background image which is part white and part black and then get the text to change from black to white when the background is black?

Is this bad web design practise?