Luminance
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Luminance
The measurable amount of light which is emitted by or reflected from a source.
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LCH stands for Luminance, Chrominance and Hue, which are three of each image's basic characteristics, affecting the viewer's perception of color.
Luminance Noise and Color Noise
Figure 1: Luminance Noise
Noise appears as a grain or as numerous tiny specks. When the specks vary in tone only, the noise is referred to as luminance noise.
Luminance - The lightness or luminance of a color is similar to its value or brightness but the two are not the same thing. In the physical world, luminance is the physically quantifiable intensity of light measured in energy per unit area.
luminance
photometric measure of the density of luminous intensity in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle
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Luminance noise graph
Our new luminance noise graph shows noise levels in both the middle gray and black patches.
Luminance
Luminance is the amount of visible light that comes to the eye from a surface.
Illuminance is the amount of light incident on a surface. Reflectance is the proportion of incident light that is reflected from a surface.
Luminance - The brightness or intensity of an image. Determined by the amount of gray in a hue, luminance reflects the lightness or darkness of a color.
Mask - To cover part of an image so it will not be affected by other operations.
luminance:
Refers to the black-and-white information, including brightness, sharpness, and contrast, encoded in a video signal or graphic image.
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luminance
The brightness or intensity of a color. The pixels in a monochrome image have a luminance of either 100 percent or 0 percent.
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luminance
The amount of luma in an image. See also chrominance.
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Luminance
The intensity of light as emitted or reflected by an object/surface. This is usually expressed in candelas per square meter (cd/m2). It is a measurement of the brightness of an object or light source.
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Luminance: One of the components of an HSL (hue, saturation, luminance) RGB (red, green, blue) image on a video monitor. It is the highest of the RGB values plus the lowest of the RGB values, dived by two. [ back to top ]
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Luminance
Lightness. The highest of the individual RGB values plus the lowest of the individual RGB values, divided by two; a component of Hue-Saturation- Lightness image.
-Illuminance - term quantifying the illumination of, or incident light falling on a surface.
-Image - two dimensional representation of a real object, produced by focusing rays of light.
#1: Use Luminance to Create an Intense Sky
On bright, sunny days, you'd think it would be easy to shoot beautiful blue skies.
Luminance
n, Physics 1 the state or quality of reflecting light. 2 the intensity of light emitted from a surface per unit area in a given direction.
(Also see Chrominance
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Luminance works the same. While you don't want to do major brightness changes to an image with this control, it can be useful in making a certain color lighter or darker.
Luminance refers to the lightness or perceived brightness of the colors we are targeting in the HSL panel.
Luminance (B&W) = (0.299 x RED) + (0.587 x GREEN) + (0.114 x BLUE)
As you can see, the green channel gets far more of a weight than the red or blue channels.
The luminance of the scene, as measured on a reflected light meter, also affects the exposure proportionately. The amount of light required for proper exposure depends on the film speed; which can be varied in stops or fractions of stops.
The luminance histogram is very close in shape to the green histogram. This reflects the heavy bias toward green referred to in the luminance histogram explanation in the first paragraph of this page.
Monitor luminance = Contrast × (Input Gamma) + Brightness
That is, while the input value to the power of the gamma value is the heart of what is going on, ...
Brightness, Luminance
A measure of a surface's or subject's reflectivity in a given direction.
The difference in luminance from the darkest to lightest areas of the image.
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Colors also have a luminance value. A deep red color, for example, might have a luminance value that is darker than 18% gray and so will be rendered more accurately and more richly with an underexposure.
Total negative contrast is dependent upon factors, such as subject luminance ratio, camera exposure level, color of light, and gamma. Gamma is only one of the factors that controls the total contrast of a negative.
An interesting effect of human vision is that we get most of the spatial information about an image from the brightness, or luminance, portion of the image and not from the color, or hue, portion.
Essentially, dynamic range (DR) refers to the range of luminance values, from the brightest to the darkest, that any device can capture.
When I "develop" the RAW file I can choose whatever color space I wish (RAW files do not contain color, only luminance) and I can use 16-bit color.
Be careful with exposures, particularly in areas of high luminance such as glaciers or snowfields. Altitude and ultra-violet rays can adversely affect exposures, particularly when measuring incident light with a hand-held device.
Another tool I use for b&w work is the Hue/Saturation/Luminance tab while still in ACR. This allows me to push similar colors farther apart or closer together, as in the cheetah image (page 52).
(1) a range of luminance values for evaluating shading through white to black; (2) a reflection or transmission scale of gray tones in steps from clear or white at one end to black at the other, ...
Gamma or gamma correction is a non-linear operation which is used to encode and decode luminance or color values in video or still image systems.
Opening up your RAW image in CS5 makes available several new control sliders: Luminance, Color, and Edge Detail. Move the Luminance slider to the right to remove grayscale (non-color) noise. Move the Color Slider to the right to remove Color noise.
So he quickly exposed a negative, using his knowledge of the moon's luminance and his own Zone system to estimate the exposure. Ansel tried to get off another image before the light changed, but it was too late.
HDR - High Dynamic Range imaging - is processing images to a higher dynamic range of luminances, increasing the difference between light and dark, either to get a better representation of the original scene or to give more impact to the image.
This is the law of diminishing luminance that states that light reduces by the inverse of the distance squared.
A typically circular device that acts to reflect light back at a subject; reflectors are designed to control contrast and color saturation, and boost luminance levels. There are two types of reflectors - lamp and board.
The Value of colors are Intensity, Brightness and Luminance Factor. Thus colors are said to have Strong or Weak Values. They can be Warm or Cold, Advancing or Receding.
A new criterion for assessing projector quality is color luminance. To measure this, the lumens of three primary colors (red, green and blue) are measured in nine fields, three of each color.
Because the LAB colorspace separates the Luminance ("Brightness") of your image from the color components it makes it possible to quickly operate on just the color or just the tone of your images.
Noise exhibits itself as luminance and chrominance noise. Luminance noise is the digital equivalent of film grain, and appears as brightness variations. Chrominance noise (or colour noise) appears as coloured splotches.
see What Is... Noise?
The first one being storage of luminance information while the second records the chrominance information. You might not believe it but that camera can accommodate a 720,000-pixel image stored on the disk in field or frame mode.
One may lower the intensity by adding white or black.
Luminance / Value: A measure of the amount of light reflected from a hue. Those hues with a high content of white have a higher luminance or value.
Pretty much what it sounds like - this increases or decreases the luminance of a photo or selected area by whatever amount you specify. 0 means no change.
Dynamic Area AF See AF Area Modes. Dynamic Range Photographers use "dynamic range" for the luminance range of a scene being photographed, or the limits of luminance range that a given digital camera or film can capture. Find out more.
Brightness range
The distinction in luminance from the darkest to lightest areas of the image
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Unfortunately these films are so contrasty, even when developed with a low- contrast developer such as dilute Solarol, that the transparencies show some reversal in the extreme highlight areas of scenes with normal luminance ranges.
Photoshop will open the RAW files from your camera directly, and will allow you to set the white and color balances, sharpness, contrast, luminance, etc. without any other software.
Chroma
The color of an image element (pixel). Chroma is made up of saturation + hue values, but separate from the luminance value.
Chromatic Adaption
Adjustment to overall color shifts, like those produced by filters.
The CIE 1931 chromaticity diagram represents all visible colors at full luminance.
It is part of the CIE-XYZ color space. Think of the diagram as the top slice of the CIE-XYZ color space.
A perceptually linear color space (RGB and CMYK are non-linear color spaces) that utilizes luminance as a means of increasing contrast and color saturation.
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LAB
LAB colours consist of a luminance or brightness component and two chromatic components.
DSLRs work best, although there are a handful of compact and EVF cameras that will also produce high-quality results. The goal is to capture the entire luminance range of the image, from overexposed shadows to underexposed highlights, ...
It appears that their algorithm looks at luminance which is most concerned with the green content of the image. If you have lots of red or blue in your image, and very little green, you'll end up with a disaster.
Super Video Home system. Clearer than the conventional VHS because it separates chrominance and luminance transmission
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Chroma - The color of an image element (pixel). Chroma is made up of saturation + hue values, but separate from the luminance value.
Noise is a term used to describe the graininess, usually associated with using high ISO settings or high speed films. There are two kinds of noise: chrominance noise consists of variations in the colour of pixels and luminance noise is a ...
 See also: Image, Camera, Light, Color, Photograph
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