A red filter
increases the contrast between the blocks because the white and red blocks will be perceived as red, while the cyan blocks will be perceived as black under the red filter
* 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.
SureFire suggests the red filter
is useful for travelling to a stand in the dark without alarming game, while the blue filter shows up a blood trail if wounded game is being followed after dark.
Used with a red filter
, the E2 will not spook deer, and a blue filter aids in following blood trails.
Adams' revelatory 1927 experience in creating "Monolith, the Face of Half Dome," one of his most-famous images, is described in the Grove Dictionary of Art: "Adams planned his photograph, waited for the exact sunlight he desired, and used a red filter
to darken the sky against the monumental cliff.
The CCD camera views the surface through a red filter
. The camera has a 1,024 x 1,024-pixel field.
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.
One camera of each pair uses a red filter
; the other, a green one.
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.