Open the Rodenstock Shutter Control interface (see icon below).

Leave the aperture at 8.0 and place the shutter speed between 1/25 and 1/30 with the current light setting (DT Photon XL). 1/30 is a good starting point if you shoot at 400 or 600ppi. Remember that this is very dependent of your light setting and position/orientation of the lamps.