FAQ Customer questions Q A Why does the alarm not sound when my exposure is complete. Be sure that there is a ringtone assigned to the alarm and the volume is up. Q A Can I expose in the shade or facing North Yes, as long as your device has a clear view of the sky then it should do the exposure correctly with your usual dose. Q A How would i know if my glass windows block UV. Expose small test pieces one inside and one outside Q A What is the pause button used for If you need to stop and continue the exposure later.There is also a technique called double exposure where it may be a useful feature. Q A My results are not the same as yours on the video All makes and model of phone use slightly different technology. You may need to do a few small test pieces to find the correct dose for your device. Q A How long should cyanotype be exposed on a cloudy day? Generally 20 min but heavy and light cloud will be different. Q A Will the app work with a UV lamp? The App is calibrated for daylight it will not work with artificial light sources. Q A Does the app work at any time of day? UV levels are lower during sunrise and sunset so you will need to increase the dose when the sun is below 45 degrees.