Brother MFC-3420C - Manual (Page 15)

USING THE MACHINE AS A PRINTER 1 - 7
Bi-Directional Printing
When Bi-Directional Printing is selected, the print heads print in
both directions and offer faster print speeds. When not selected, the
print heads will only print in one direction to provide higher quality
printouts.
Media Type Color/Grayscale Print Quality Selection
Plain Paper Color/Grayscale Fast, Normal, Fine, S.Fine
Inkjet Paper Color Fine, S.Fine, Photo
Grayscale Fine, S.Fine, Photo
Glossy Paper (4 or 3 color) Color S.Fine, Photo
Grayscale S.Fine, Photo
Transparencies Color/Grayscale Fine, S.Fine
The factory settings are shown in bold.