Currently, projection screens are being installed off-center (sometimes two screens are
installed) so that the chalkboard can be used at the same time as material is being projected. This
requires that the chalkboard be illuminated without any light spilling onto the projection screen.
Illumination of the chalkboard or marker board should be 10-15 lumens distributed
uniformly across the entire writing surface. The lights over the writing surface should be
controlled in separate sections to permit illumination of a portion of the board while one projection
screen is in use. Proper selection and installation of the board lighting and/or baffles should
ensure that the lamps in the fixtures will not be visible to students seated in the front rows. In
addition, the fixtures should not interfere with raising/lowering the screen(s). Board lighting
should not cast any light on the projection screens. Whenever possible, this should be achieved by
placing the lighting behind the screens (between the screens and the chalkboard) and sitting
directly on the top edge of the board. This requires that the lighting have a narrow profile so the
screen doesn’t need to be too far forward. In cases where the nature of the screen mounting
precludes this, lighting fixtures should be selected that sufficiently control the spread of the light
so that no light spills over onto the adjacent projection screen.