Using the cameraThe Matchbox Pinhole camera has an f number of about f90. There's no need to be very accurate about exposure times when using colour print film, use the following as a rough guide when using ISO100 or 200 film.Outside, sunshine: 1 or 2 secondsOutside, cloudy conditions: 5 secondsIndoors, normal room lighting: 5 - 10 minutesdamn .. 5-10 min
yep, 10 mins is nothing odd for a pinholeYou have to experiment though, every box is different.