Alan, I agree that David's method is not a substitute for C41 process - it won't produce colour negatives. However, it is a viable method for developing C41 film in B&W chemistry. It gives better negatives (for both enlarging and scanning) than the straight forward development of C41 film in B&W chemistry. If OP choses to develop C41 film in B&W chemistry, then David's method is worth looking at.