So I used the defect list option in cosmetic correction and like you say it's pretty straightforward particularly as my sensor has really just 1 bad column. The individual cosmetically corrected frames to me look better but the final integrated result is still the same??? So not sure what to do. I am pretty certain I am applying it correctly. I tried using CC as a new instance during batch preprocessing and also applying CC after calibration was complete. No difference. I created the defect list by opening the cosmetic correction process, clicking on the "defect list" box at the bottom, opening a raw uncalibrated frame, clicked on "column" at the bottom of the defect list window and then clicked on a single pixel in the bad column of the raw frame. The defect then appears in the list with what I believe is the X value of the column. I save as a text file and then reload during the cosmetic correction process. Maybe this is wrong I am hoping? Not sure why there would be zero difference in the end result. I used the same integration with both (windsorized sigma) I have the 2 files attached. PI2 is cosmetically corrected WITHOUT defect map included. PI3 is WITH defect map included for supposed correction