Printing or saving the error list

HTML Tidy is very good. I'm teaching myself and getting lots of things wrong.
When I feed my work to Tidy, I can save the corrected version, and I can open the old and new docs side by side and compare them, but to see WHY a change was necessary, I have to go through the procedure again, because I can't find a way to save the error list. I think that the only way I'll improve is to understand how I'm going wrong, as well as having my mistakes corrected.  
This may not be a problem for everyone, but I have LOTS of errors.
Thank you so much for your help. I have many of the Dave Raggett pages in a folder and have learned heaps.
Fay Johnston,
Australia.