COLOR

  • About green screens

    hackaday.com/2015/02/07/how-green-screen-worked-before-computers/

     

    www.newtek.com/blog/tips/best-green-screen-materials/

     

    www.chromawall.com/blog//chroma-key-green

     

     

    Chroma Key Green, the color of green screens is also known as Chroma Green and is valued at approximately 354C in the Pantone color matching system (PMS).

     

    Chroma Green can be broken down in many different ways. Here is green screen green as other values useful for both physical and digital production:

     

    Green Screen as RGB Color Value: 0, 177, 64
    Green Screen as CMYK Color Value: 81, 0, 92, 0
    Green Screen as Hex Color Value: #00b140
    Green Screen as Websafe Color Value: #009933

     

    Chroma Key Green is reasonably close to an 18% gray reflectance.

     

    Illuminate your green screen with an uniform source with less than 2/3 EV variation.
    The level of brightness at any given f-stop should be equivalent to a 90% white card under the same lighting.

    , ,
    Read more: About green screens
  • HDR and Color

    https://www.soundandvision.com/content/nits-and-bits-hdr-and-color

    In HD we often refer to the range of available colors as a color gamut. Such a color gamut is typically plotted on a two-dimensional diagram, called a CIE chart, as shown in at the top of this blog. Each color is characterized by its x/y coordinates.

    Good enough for government work, perhaps. But for HDR, with its higher luminance levels and wider color, the gamut becomes three-dimensional.

    For HDR the color gamut therefore becomes a characteristic we now call the color volume. It isn’t easy to show color volume on a two-dimensional medium like the printed page or a computer screen, but one method is shown below. As the luminance becomes higher, the picture eventually turns to white. As it becomes darker, it fades to black. The traditional color gamut shown on the CIE chart is simply a slice through this color volume at a selected luminance level, such as 50%.

    Three different color volumes—we still refer to them as color gamuts though their third dimension is important—are currently the most significant. The first is BT.709 (sometimes referred to as Rec.709), the color gamut used for pre-UHD/HDR formats, including standard HD.

    The largest is known as BT.2020; it encompasses (roughly) the range of colors visible to the human eye (though ET might find it insufficient!).

    Between these two is the color gamut used in digital cinema, known as DCI-P3.

    sRGB

    D65

     

    , ,
    Read more: HDR and Color
  • What is OLED and what can it do for your TV

    https://www.cnet.com/news/what-is-oled-and-what-can-it-do-for-your-tv/

    OLED stands for Organic Light Emitting Diode. Each pixel in an OLED display is made of a material that glows when you jab it with electricity. Kind of like the heating elements in a toaster, but with less heat and better resolution. This effect is called electroluminescence, which is one of those delightful words that is big, but actually makes sense: “electro” for electricity, “lumin” for light and “escence” for, well, basically “essence.”

    OLED TV marketing often claims “infinite” contrast ratios, and while that might sound like typical hyperbole, it’s one of the extremely rare instances where such claims are actually true. Since OLED can produce a perfect black, emitting no light whatsoever, its contrast ratio (expressed as the brightest white divided by the darkest black) is technically infinite.

    OLED is the only technology capable of absolute blacks and extremely bright whites on a per-pixel basis. LCD definitely can’t do that, and even the vaunted, beloved, dearly departed plasma couldn’t do absolute blacks.

    ,
    Read more: What is OLED and what can it do for your TV
  • Polarised vs unpolarized filtering

    A light wave that is vibrating in more than one plane is referred to as unpolarized light. … Polarized light waves are light waves in which the vibrations occur in a single plane. The process of transforming unpolarized light into polarized light is known as polarization.

    en.wikipedia.org/wiki/Polarizing_filter_(photography)

     

    Light reflected from a non-metallic surface becomes polarized; this effect is maximum at Brewster’s angle, about 56° from the vertical for common glass.

     

    A polarizer rotated to pass only light polarized in the direction perpendicular to the reflected light will absorb much of it. This absorption allows glare reflected from, for example, a body of water or a road to be reduced. Reflections from shiny surfaces (e.g. vegetation, sweaty skin, water surfaces, glass) are also reduced. This allows the natural color and detail of what is beneath to come through. Reflections from a window into a dark interior can be much reduced, allowing it to be seen through. (The same effects are available for vision by using polarizing sunglasses.)

     

    www.physicsclassroom.com/class/light/u12l1e.cfm

     

    Some of the light coming from the sky is polarized (bees use this phenomenon for navigation). The electrons in the air molecules cause a scattering of sunlight in all directions. This explains why the sky is not dark during the day. But when looked at from the sides, the light emitted from a specific electron is totally polarized.[3] Hence, a picture taken in a direction at 90 degrees from the sun can take advantage of this polarization. Use of a polarizing filter, in the correct direction, will filter out the polarized component of skylight, darkening the sky; the landscape below it, and clouds, will be less affected, giving a photograph with a darker and more dramatic sky, and emphasizing the clouds.

     

    There are two types of polarizing filters readily available, linear and “circular”, which have exactly the same effect photographically. But the metering and auto-focus sensors in certain cameras, including virtually all auto-focus SLRs, will not work properly with linear polarizers because the beam splitters used to split off the light for focusing and metering are polarization-dependent.

     

    Polarizing filters reduce the light passed through to the film or sensor by about one to three stops (2–8×) depending on how much of the light is polarized at the filter angle selected. Auto-exposure cameras will adjust for this by widening the aperture, lengthening the time the shutter is open, and/or increasing the ASA/ISO speed of the camera.

     

    www.adorama.com/alc/nd-filter-vs-polarizer-what%25e2%2580%2599s-the-difference

     

    Neutral Density (ND) filters help control image exposure by reducing the light that enters the camera so that you can have more control of your depth of field and shutter speed. Polarizers or polarizing filters work in a similar way, but the difference is that they selectively let light waves of a certain polarization pass through. This effect helps create more vivid colors in an image, as well as manage glare and reflections from water surfaces. Both are regarded as some of the best filters for landscape and travel photography as they reduce the dynamic range in high-contrast images, thus enabling photographers to capture more realistic and dramatic sceneries.

     

    shopfelixgray.com/blog/polarized-vs-non-polarized-sunglasses/

     

    www.eyebuydirect.com/blog/difference-polarized-nonpolarized-sunglasses/

     

    , ,
    Read more: Polarised vs unpolarized filtering
  • StudioBinder.com – CRI color rendering index

    www.studiobinder.com/blog/what-is-color-rendering-index

    “The Color Rendering Index is a measurement of how faithfully a light source reveals the colors of whatever it illuminates, it describes the ability of a light source to reveal the color of an object, as compared to the color a natural light source would provide. The highest possible CRI is 100. A CRI of 100 generally refers to a perfect black body, like a tungsten light source or the sun. ”

    www.pixelsham.com/2021/04/28/types-of-film-lights-and-their-efficiency

    ,
    Read more: StudioBinder.com – CRI color rendering index

LIGHTING

Collections
| Explore posts
| Design And Composition
| Featured AI

Popular Searches
unreal | pipeline | virtual production | free | learn | photoshop | 360 | macro | google | nvidia | resolution | open source | hdri | real-time | photography basics | nuke




Subscribe to PixelSham.com RSS for free
Subscribe to PixelSham.com RSS for free