Luminosity Control In Photoshop
What does it take to visualize luminosity in black-and-white and color photography, then see and control it in Photoshop?
By George DeWolfe ...
Luminosity
The petals of the red flowers caught direct sunlight, so their red color became clipped, even though the rest of the image remained within the histogram.
Figure 2: Day Luminosity Response
The result of the cone's response and the disparate numbers of the red, green, and blue cones is that day luminance is dependent on both the intensity and the wavelength of the light that strikes the eye.
To give it a try, first select the luminosity channel for the image and then invert the selection. Now create a new curves adjustment layer but don't change the curve from its default. Click on "OK.
Luminosity
Luminosity measured in lumens, and describes the brightness of either a light source or a reflective surface. Luminosity also measures the highest to the lowest RGB components of an image.
LUMINOSITY - the brightness of a light source.
LZW - Lossless compression when storing images.
CIE luminosity function
a plot of the relative magnitude of the visual response as a function of wavelength from 389 to 780 nm adopted by CIE in 1924.
Luminosity:
Brightness or intensity of either a light source or a reflective surface.
Intro ...
Luminosity - brightness of either a light source or a reflective surface.
Luminous flux - intensity of a light source, measured in lumens.
jump to top ...
The luminosity histogram, as the name suggests, shows the combined value of each pixel on one graph. So we can see at a glance whether the photo is too dark or too bright.
The Problem ...
10. Luminosity emphasizes the shadows and enhances brightness.
11. Micro-contrast improves the contrast of the details.
12. Smoothing affects the dynamic range of highlights and shadows.
Examples of dark matter include planets, black holes, white dwarfs (because they are low luminosity) and more exotic things like weakly interacting particles.
To quote from the beginning of this page, "Slide and negative scans have a much greater tonal and luminosity range than scans made from prints.
Color is the combination of three elements-hue, saturation and luminosity. Brightness, also called luminosity, also called value, can be confused with saturation.
This graph shows noise as standard deviation of luminosity at all of the EOS 550's high ISO noise reduction settings, from ISO 1600 and above.
For this particular setup, I gave a slight increase to vibrance and clarity (midtone contrast), and the blue in the sky and water were deepened slightly by lowering the blue luminosity, ...
Practical imaging systems, digital and film, have a limited "dynamic range": the range of luminosity which can be reproduced accurately.
This value describes the luminosity, the luminous intensity. It is the amount of light emitted by a color.
The dynamic range (or luminosity range) of the scene is the ratio between the largest and the smallest values of luminosity in the scene. The dynamic range of a sensor is the ratio between the largest and the smallest signal it can generate.
Low contrast compositions use colors within a narrow range of luminosity or brightness levels.
Moderate contrast
moderate contrast compositions use colors within a moderate range of luminosity or brightness levels.
High contrast ...
This method works well for highlighting parts of the animals, emphasizing their shape, or altering the luminosity of your background to better suit your subject. I used it to get the effect of a black seamless in the baboon picture on page 54.
Increased luminosity also increases color depth
(saturation), edge definition (clarity) and light-to-shadow radio (contrast). Increased light also
allows the camera to produce the same images at a lower ISO sensitivity, which relates to higher ...
By loading the luminosity mask (Alt-Ctrl-~), inverting it (Shift-Ctrl-I), then creating a Levels layer, you can reduce contrast without killing saturation like Gamma would. Adjust the white point to brighten up the shadows only.
It did show a histogram, however it was marked "luminosity" which is useless since problems with exposure in any one of the R, G or B channels ruins an image and will not show on a luminosity histogram.
There is a dramatic luminosity difference between the pale sky and the black rocks in the foreground. The automatic conversion creates a pleasing image [46] but the sky is too bright as compared to the ground.
The luminosity slider adjusts the global brightness of the picture. If you pull a lot of detail from the shades, the pictures will look too bright. In most cases I have a slightly negative value here.
You can adjust the luminosity control to modify the overall brightness of the image. The ‘Micro Contrast' setting controls any haloing you may get around objects that are dark against light in the image.
Acronym for Hue/Brightness/Luminosity. See HSI.
heuristics
A set of rules derived from experimentation or experience.
Brilliance
Strength of light reflected from a surface. It is sometimes an substitute term for luminosity.
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Information provided by: SWPP BPPA
More Photographic Terms ...
-Brilliance - intensity of light reflected from a surface. It is sometimes an alternative term for luminosity.
-Broad lighting - portrait lighting in which the main light source illuminates the side of the face closes to the camera.
CIE LAB ( L*a*b* )
A colour model to approximate human vision. The model consists of three variables: L* for luminosity, a* for one colour axis, and b* for the other colour axis.
If you want still more inside info on Avenaim’s technical wizardry, wait for the 2006 publication of his book Luminosity, which will explain precisely how he shot dozens of his most famous portraits.
Colour Contrast Analyser is a Firefox extension that lists color combinations used in your web pages. It lays out the colors in a table that summarises the foreground color, background color, luminosity contrast ratio, ...
Try this test: take a good print that you have, and print it again, with 10% less time. Printing AS LIGHT AS YOU CAN will give your prints luminosity, a kind of glowing quality.
Perhaps he liked the solarization because its luminosity resembled that in scenes that he was fond of depicting. If the solarization had no further significance to Degas, it was nevertheless an artistic application of solarization, unwitting or not.
In the Photo Filter dialogue box, enter these settings: Filter-Sepia, Density-50 percent, Preserve Luminosity-selected. You can experiment with altering the density to change the image [source: Apple].
 See also: Image, Light, Camera, Color, Photograph
  
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