How can I remove all the pixels in an image except pixels colored black?

I have taken pictures of drawings, and I want a script that will leave me with the 'shell' of my original drawings. All I want to remain from my original drawings, are pixels that are colored black. Can someone help me?

Answer 1

[sandeep]

I need to see the image to advise on that. However, I believe basic thresholding operation would help solve the problem.