Lightness (sometimes called value or tone) is a property of a color, or a dimension of a color space, that is defined in a way to reflect the subjective brightness perception of a color for humans along a lightness–darkness axis. A color's lightness also corresponds to its amplitude.

Various color models have an explicit term for this property. The Munsell color model uses the term value, while the HSL color model and Lab color space use the term lightness. The HSV model uses the term value a little differently: a color with a low value is nearly black, but one with a high value is the pure, fully saturated color.

In subtractive color (i.e. paints) value changes can be achieved by adding black or white to the color. However, this also reduces saturation. Chiaroscuro and Tenebrism both take advantage of dramatic contrasts of value to heighten drama in art. Artists may also employ shading, subtle manipulation of value.

The Munsell value has long been used as a perceptually uniform lightness scale. A question of interest is the relationship between the Munsell value scale and the relative luminance. Aware of the Weber–Fechner law, Munsell remarked "Should we use a logarithmic curve or curve of squares?" Neither option turned out to be quite correct; scientists eventually converged on a roughly cube-root curve, consistent with the Stevens power law for brightness perception, reflecting the fact that lightness is proportional to the number of nerve impulses per nerve fiber per unit time. The remainder of this section is a chronology of lightness approximations, leading to CIELAB.

Larry Weber (born July 7, 1955) is an American entrepreneur and globally known expert in public relations and marketing services. He is founder and chairman of W2 Group, a marketing services ecosystem organized to help chief marketing officers in their new role as builders of communities and content aggregators. W2 Group includes Digital Influence Group, a social media marketing agency, Racepoint Group, a global public relations agency, and Two Martinis.

In 2001 Weber founded Weber Shandwick, one of the largest public relations agencies in the world. He also co-founded the Massachusetts Innovation & Technology Exchange(MITX), the largest interactive advocacy organization in the world. Weber is Chair of the MITX Board of Directors and serves on the Executive Committee of the Council on Competitiveness, a non-governmental organization working to ensure U.S. economic prosperity.

Weber is the author of four books on business and marketing – The Provocateur: How a New Generation of Leaders are Building Communities, Not Just Companies (2002), Marketing to the Social Web: How Digital Customer Communities Build Your Business (1st ed. 2007, 2nd ed. 2009),Sticks & Stones: How Digital Business Reputations are Built Over Time and Lost in a Click (2009), and Everywhere: Comprehensive Digital Business Strategy for the Social Media Era (2011).

Scott Benton White (June 8, 1970 – October 21, 2011) was a Democratic member of the Washington State Senate, representing the 46th legislative district. His district included much of North Seattle, including the neighborhoods of Northgate, Greenwood, Bitter Lake, Broadview, Haller Lake, Pinehurst, Olympic Hills, Maple Leaf, Lake City, Wedgwood, View Ridge, Laurelhurst, and Windermere.

On October 21, 2011, Senator White was found dead in a hotel room at Suncadia Resort. The coroner's report indicated that the cause was a cardiac problem linked to a previously-undiagnosed enlarged heart.

During the 2011-2012 term, White's assignments in the Senate would have included serving in leadership as Majority Whip, as Vice Chair of the Transportation Committee, and serving on the Higher Education and Rules Committees.

White served in a variety of professional and community leadership positions before being elected to the legislature. He is a former Chief of Staff to the Metropolitan King County Council, and he has served as budget and policy staff in both the Washington State Legislature and King County government. White has taught graduate-level courses in public policy at the Daniel J. Evans School of Public Affairs at the University of Washington. In 2004 he was selected as a Marshall Fellow by the German Marshall Fund of the United States. White has served on the board of Humanities Washington, the Public Policy Committee of the United Way of King County, and is an award winning grassroots organizer with the Democratic Party.