Python convert True False matrix to image

I have a matrix consisting of True and False values. I want to print this as an image where all the True values are white and the False values are black. The matrix is called indices. I have tried the following:

indices = indices.astype(int)  #To convert the true to 1 and false to 0
indices*=255                   #To change all the 1's to 255
cv2.imshow('Indices',indices)
cv2.waitKey()

This is printing a fully black image. When I try, print (indices==255).sum(), it returns a values of 669 which means that there are 669 elements/pixels in the indices matrix which should be white. But I can only see a pure black image. How can I fix this?