je peux avoir un lien sur ces sites? c'est pour comprendre
edit: extrait de la doc Kodak 
"PRINTING NEGATIVES
Note: 
BW400CN Film is optimized for printing on color 
negative papers. BW400CN Film can be printed on 
traditional black-and-white papers, but the printing time will 
be substantially longer and require a higher contrast grade of 
paper (3.5 to 4). For best results when printing onto 
black-and-white paper, we recommend a traditional 
black-and-white film su
ch as KODAK PROFESSIONAL 
TRI-X 400 or T-MAX 100 Film.
BW400CN Film is designed to deliver excellent 
black-and-white prints on professional color papers. When 
printing on color papers, you 
can also create special-effect 
tones, such as sepia, simply by changing the printer color 
balance"
https://www.blende7.at/datenblaetter/ko ... w400cn.pdf