However front projection has some obvious disadvantages as it is very sensitive to ambient light. The contrast level is directly dependent on the amount of ambient light striking the screen.
Using traditional (i.e. white) front projection the black parts of the images are not really black, but are perceived as such because hardly any light from the projector strikes these parts of the screen. The contrast will be diminished by the amount of ambient light striking the screen.
Since this Guide was first produced, dnp has now produced an ‘optical’ front projection screen – the dnp Supernova Screen. This revolutionary screen absorbs ambient light, remaining near black until projected light strikes it. Therefore it is now possible to use front projection in situations of high ambient light. Please see other sections for specifics.
One potential disadvantage of front projection is the possibility of casting shadows on the image e.g. a lecturer walking in front of the screen. Not only can the shadows affect the image for the audience, it comprises a risk to the eyes of the presenter. In such cases you should consider rear projection as your preferred option.
Furthermore, as the projector has to be placed in front of the screen it is often installed in the ceiling where it is visible and also noisy. If potential noise pollution is an issue, again you should think of rear projection as the preferred option.