Digital BW, The Print

Dear all:

again, my excuses for a very simple question. As you might know, English is not my first 
language (nor even the third). I have been trying to find a translation /explanation of the 
technical word "bronzing", with no success. Although I intuitively guess its general 
meaning, I would love to have a not-that-intuitive explanation. Would any of you be so 
kind to explain it to me? Maybe in order not to clog the list, you can simply make this 
"opus misericordiae" sending me an email.
Thank you very very much
Jesus R. Velasco