Other contrast-enhancement devices Hoods and mesh screens may also be used to increase contrast.
Hoods block unwanted illumination from the workplace.
Effective hoods must surround the VDT image and extend close to the viewer's face. In fact, commercial hoods have compliant forehead rests. Homemade hoods are usually fashioned from cardboard by the user in an attempt to cope with situations of poor room illumination. This is always almost a poor solution. A typical result is a shadow across the screen.