Projects: Recovering Spectral Reflectance under Commonly Available Lighting Conditions. Recovering the spectral reflectance of a scene is important for scene understanding. Previous approaches use either specialized filters or controlled illumination where the extra hardware prevents many practical applications. In this paper, we propose a method that accurately recovers spectral reflectance from two images taken with conventional consumer cameras under commonly available lighting conditions, such as daylight at different times over a day, camera flash and ambient light, and fluorescent and tungsten light. Our approach does not require camera spectral sensitivities or the spectra of the illumination, which makes it easy to implement for a variety of practical applications.
Based on noise analysis, we also derive theoretical predictors that answer: (1) which two lighting conditions lead to the most accurate spectral recovery overall, and (2) for two given lighting conditions, which spectral reflectance is more likely to be estimated accurately. Handprint. LBNL Pigment Database: [Y02] Cadmium Yellow Light. Drop2Color by Zsolt. Drop2Color v. 3.10 a program to visualize the color of mixed paint recipes by Zsolt --- under construction: version 3.6 is shown below up to Download section --- Link to Drop2Color version 2.4 - English version Introduction Program description Notes List of updates Application examples Download Disclaimer Acknowledgments Frequently asked questions Introduction: This program converts the paint mixture into chromatic coordinates, shows the resulting color on the monitor and also places it in Munsell Space in 3D.
Program description: This program is written as a MATLAB script and for its execution it is necessary to have installed "MATLAB Component Runtime library (MCR)". In area (1) we define the paint recipe to be analyzed. The Dimensions of Colour. Paint mixing processes Artists who use physical paint media mix their colours in three basic ways: 1. by physical mixing, 2. by glazing (using superimposed transparent paint layers), and 3. by interspersing small patches of colour that optically blend completely or partially at the intended viewing distance. The physical mixing of paints is often described simply as subtractive, but in reality a component of additive-averaging mixing is usually also involved.
In a physical mixture of paints, most light bounces around and interacts with grains of all components in the mixture before emerging, so that each component has the opportunity to influence the colour of the light. However, unless the paints involved are perfectly transparent, some light will be back-scattered off grains of one or other component alone (Fig. 6.1.1). > Art Spectral Imaging. Color. It is common practice to define pure colors in terms of the wavelengths of light as shown. This works well for spectral colors but it is found that many different combinations of light wavelengths can produce the same perception of color. This progression from left to right is from long wavelength to short wavelength, and from low frequency to high frequency light. The wavelengths are commonly expressed in nanometers (1 nm = 10-9 m).
The visible spectrum is roughly from 700 nm (red end) to 400 nm (violet end). The letter I in the sequence above is for indigo - no longer commonly used as a color name. The inherently distinguishable characteristics of color are hue, saturation, and brightness. White light, or nearly white light from the Sun, contains a continuous distribution of wavelengths. American Cinematographer: The Color-Space Conundrum. Jump to: “The Color-Space Conundrum, Part 2” by Douglas Bankston Seabiscuit photo courtesy of Universal Pictures When John Schwartzman, ASC wanted to avoid the resolution-degrading optical blowup of Seabiscuit (2003), he took the Super 35mm footage into a digital-intermediate suite at Technicolor’s DI facility, Technique (now TDI), where the process was accomplished in a computer.
Though the digital era is in its infancy, its tools offer cinematographers unprecedented control over their imagery. And new digital tools — file formats, projectors, Look-Up Tables, cameras, algorithms for color sampling, compression and conversion, etc. — are being developed at a breakneck pace. With manufacturers pursuing their own directions and goals, this has led to a digital realm without order, beyond the controlled borders of a select group of post facilities who have been engineering their own proprietary DI workflow solutions.
X11 Color Space. This page contains a few Python programs that work with and display the X11 color space. color_space.py Displays the named X11 colors as spheres in RGB space. The user can zoom and rotate the color cube. Clicking on a sphere prints the color names and attaches a label. Here is a screen shot looking down the white-black axis: And here is the documentation. color_list.py. Munsell Color System; Color Matching from Munsell Color Company. Munsell Color Space Munsell hue, value and chroma can be varied independently so that all colors can be arranged according to the three attributes in a three-dimensional space. The neutral colors are placed along a vertical line, called the “neutral axis,” with black at the bottom, white at the top, and all grays in between. The different hues are displayed at various angles around the neutral axis. Visualizing Color Space - O'Reilly Digital Media Blog.
Charles Poynton. COULEUR.ORG.
Home. Gamutvision - explore color spaces, gamut mappings, and rendering intents. Welcome to Bruce Lindbloom's Web Site.