When students look at the figure through a red filter
, the area without any red component will be perceived as black, while the rest will be perceived as red
Take pictures without an infrared or red filter
on your lens.
So black-and-white scanners used for OCR/ICR of HCFA forms often have a red filter
in front of the digital camera component of the scanner, the CCD arrays.
The CCD camera views the surface through a red filter
In macaque and humans, color vision sensitivity is so high that a sub-threshold white light becomes visible if passed through a broadband red filter
(Kodak Wratten #25).
For instance, one might place a red filter
along a spot of the circumference of the beacon, producing a red spot on the opposing wall.
The Chili Red filter
will debut as part of the Chili Red Alliance multi-vendor campaign at the Gourmet Show.
The red filter
lets only red wavelengths pass through.
Exposing the original photo through a red filter
creates a negative from which a printing plate is made, in a process not unlike making a regular photo from a negative.
Marlboro went from a red filter
tip targeted to women, with a minor share of market, to the position of leader of the pack.
He used a deep red filter
for his next shot, which caused the sky to darken to a dark gray, and to emphasise the white snow on the Half Dome.
A reddish feature, for example, reflects red light but absorbs green and blue light, so it will appear bright through a red filter
but dark through a green or blue filter.