After the first 30 seconds, agitate for 5 seconds at 30-second intervals. Agitation should consist of 2 to 5 cycles, depending on the contrast you need and the type of tank. Wind each roll onto a spiral reel. Many racks can hold up to 30 rolls of 35 mm film or 18 rolls of 120-size film. Lower the rack, basket, or spindle into the developer, and tap it quickly and sharply against the tank to dislodge air bubbles from the surface of the film.
Air bubbles can interfere with development and produce low-density circles on the film.
Be sure to keep the reels in the solution. Do not agitate the rack, basket, or spindle for the remainder of the first minute. Alternate the direction of tilting the rack, basket, or spindle. Rock the tray immediately to make sure the film is covered with solution. Next, raise and lower the right-hand side, then the near side again.