Comparison between the WFC3 IR persistence models calculated taking into account 96 h of previous observations (left column) and the persistence models available at MAST, with a limit of 16 h of lookback time (right column). Top panels: persistence models for dataset ib5x22b8q. Bottom panels: persistence models for dataset icxt25byq. The images corresponding to the same dataset are at the same colour scale. Note on the top left panel a background of persistence covering the complete field of view caused by the flat calibration lamp in the previous hours to the observation of the HUDF, not detected on the persistence model available at MAST (top right panel).