Hi @Zhang, if I remember correctly you’re not actually using the OpenFlexure Microscope software, but you are using the LST calibration code from the calibration plugin.
If that’s the case, it should be relatively simple to readjust the gain/exposure settings after calibrating. If you run the calibration procedure as you are currently doing, then switch to the UV illumination, then re-run ru.adjust_shutter_and_gain_from_raw(picamera) it should result in a higher gain, and brighter images. As this doesn’t re-enable anything automatic, it won’t change the white balance. If you run ru.adjust_white_balance_from_raw(picamera) once, that will update the white balance but then keep it constant for all future images.