How increase grain during darkroom printing? Depends on film, chemicals and focus while shooting.
Darkroom effects (dodging and burning)
Darkroom contrast control
Grade (0-5) : high contrast turn things into black or white areas ; low contrast makes a flat image as a bad photocopy
Exposure (in camera and in print room) influences contrast results
1. Use graded papers that come in range from 1 (lowest contrast) to 5 (the highest contrast).Using graded paper is easy. If you’re print is flat, step up a grade and try again. If your print has too much contrast, simply step down a grade.
2.Use variable contrast (VC paper). yYou produce a variety of contrasts using the same paper, simply by changing the color of the light you project onto the paper.
Magenta filter increases contrast + absorb more light > need to increase exposure time ; yellow filter decreases contrast
3. Filter sets (Ilford or Kodak)
Underexposure : thin (almost invisible) negatives with low density > low contrast prints > use a high grade paper or high number filter to correct it.
Overexposure : dark which negatives > usually (but not always) high contrast prints > use a low grade paper or yellow filter
The agitation during processing affects the contrast of your film (read chemical instructions, experiment and find your preferred settings)
Agitating it too much will result in large grain and high contrast. Agitating too little will result in thin negatives and flat prints.