This is a timeline of photos of a glow in the dark star ceiling under different lighting conditions.

It took me 20 minutes to put up 100 star stickers. (Only the brightest were detected by the camera.)

Daylight ~ This is a back room which doesn't receive direct sunlight. The white decals blend in almost invisibly to the white ceiling.

Daylight with room light on ~ Late afternoon ~ The decal edges are picked up by the room light. 

Twilight with room light ~ Again the lights changes the appearance of the decals.

Night time ~ Dim light is washing in from another room. The decals were charged by leaving the light on for 10 minutes.

Complete darkness, fully charged. The decals will continue to glow all night with a whitish afterglow colour.