I place the Graylab 300 timer about 20Ē (about 50cm) above my developing trays on a shelf. The shelf overhangs the trays. The timer is high enough and far enough back on the shelf so that there is no direct line from any part of the phosphorescent face to the trays, yet the timer is still close and easy to see. Any light coming directly from the timer face towards the trays is intercepted by the forward part of the shelf.
Apparently, whatever light reflects off of various surfaces is far too weak by the time it reaches the open try to have any effect on my films or papers. The fastest sheet film I use is ASA 320 or ASA 400 and is developed in the same trays as papers. I donít see any fogging effect on these relatively fast films, which are likely more light sensitive than the papers.