Safe level of daylighting for artefact conservation in historic buildings is a difficult task to achieve. Previous studies indicated that lighting problems in historic museum galleries were mainly due to unshaded walls that allowed direct sun penetration over the display areas. Ceiling geometry can also affect the daylighting performance significantly, particularly on the interior distribution of light. Malaysia, with hot and humid climate, and tropical sky conditions receives plenty of natural light all year around. The fluxes in natural lighting exposures confirm the need for strategic daylight control programme in the exhibition gallery. The study aims to assess the ceiling geometry contribution for four orientations; North, East, South and West through computer simulations. The research approach was based on comparisons between pitched and flat ceiling simulation output data. Further comparisons were performed with the recommended lighting limits for conservation of artefacts. The comparisons allowed better understanding of light damage issues and highlight the control of daylighting distributions through realistic predictive images and ceiling geometry designs. The results showed that the types of exhibits materials and its placement are affected by the ceiling geometry and constant changes in natural lighting exposure. The study confirms that ceiling geometry can act as a control mechanism with the environment physical features as part of preventive conservation criteria in the exhibition gallery. Thus, a systematic light-monitoring programme in the exhibition gallery is necessary to control illuminance level and cumulative exposure limits, for artefact preservation.