Open Gleam Lagoon

Old English open, unobstructed — used as a color modifier since the eighteenth century for hues that read as airy or uncrowded. Open blue, open green: moderate saturation combined with optical spaciousness, the slight visual breath of a hue that doesn't crowd the surface it covers. Sits at the crisp-bucket center alongside clear.

Old English glǣm, brightness-or-shine. As a color modifier, gleam implies a low-and-glancing-and-bright quality, the visual register of polished-armor-and-river-water-gleam hand-polished-and-glancing-and-bright polished-armor-and-river-water-and-blade-edge gleamed-and-polished-and-glancing surfaces under polished-armor-and-river-water blade-edge-and-helm-and-shield medieval-tournament-light. Sits at the modifier-and-mood end of the grid, parallel to glint and sheen in usage.

A shallow body of saltwater partially or fully enclosed by a barrier — coral atoll lagoons in the Pacific, Venice's Laguna Veneta, the Florida Keys' backcountry. The color refers to the average reflectance of a calm tropical lagoon at midday: a saturated, slightly muted blue-green with the optical clarity of shallow water over white sand. Brighter than reef, cooler than aquamarine, with the postcard weight of a Pacific atoll seen from above.