Buchanan Studios Blog

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Posts Tagged ‘light

Photographic Term of the Week: Additive Color

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Additive color is the process of creating colors by combining light. IE, white light (neutral) would be created by combining equal amounts of red, green and blue light. Conversely, subtractive color is the process of creating colors by filtering reflected light. IE, black (neutral) would be created by filtering equal amounts of cyan, magenta and yellow. Additive color is used in transmissive displays (televisions, monitors, backlit transparencies) subtractive color is used in reflective displays (prints)

Note regarding subtractive color in commercial printing: Ideally the combination of C,M,Y inks would produce a perfect black, but in practice they do not. Therefore the addition of a fourth black ink (referred to as K) is used.

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Written by stevebuchanan

February 17, 2012 at 9:41 am

Photographic Term of the Week: Barn Doors

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Barn Doors are light modifiers added to an artificial light. Usually consisting of two or four independently hinged cards or flags used to block light from a particular portion of a scene.

Written by stevebuchanan

February 10, 2012 at 9:38 am

Photographic Term of the Week: Chiaroscuro

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Chiaroscuro is an Italian term that literally means light-dark. It refers to the tonal contrasts that give a represented object shape and definition or greater dramatic representation.

See this wonderful example from the National Gallery in London

Written by stevebuchanan

January 27, 2012 at 10:57 am

Photographic Term of the Week: Color Temperature

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Color Temperature is the description of the color of a light source. Expressed in degrees Kelvin, it’s based on an ideal radiator of light at a particular temperature. Daylight is usually thought of as 5500˚K, incandescent usually 3200˚ or 3400˚ Perceptually, our brains don’t see this difference in color easily, but photographic sensors and films do. Manual or automatic color balance is fairly easily achieved with digital still and video cameras, but situations with differing light sources and therefore differing color temperatures can present challenges.

Written by stevebuchanan

January 20, 2012 at 10:46 am

Photographic Term of the Week: Chromatic Aberration

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This week we begin a new series of defining photographic terms. This week…

Chromatic Aberration – (aka Achromatism) is a shortcoming of lenses where different colors of light are focused onto different planes. IE Blue wavelengths focusing nearer than red. Since all colors we see are made up of combinations of differing wavelengths of light chromatic aberration will cause a loss of sharpness in the color transitions occur. Generally speaking, higher end lenses reduce CA to the point where it’s not detectable with current camera systems.

Image by Stan Zurek

Other lens shortcomings (aberrations) include spherical aberrations, distortion and curvature of field.

Written by stevebuchanan

January 5, 2012 at 10:25 am