Umbala

Umbala umbono obonakalayo osuselwe ku-spectrum kagesi. Nakuba umbala ungeyona into yemvelo yento, ukubona kombala kuhlobene nokumunca ukukhanya kwento, ukucwebezela, ukukhishwa kwe-spectra, nokuphazamiseka. Kubantu abaningi, imibala ibonakala ku-spectrum yokukhanya ebonakalayo enezinhlobo ezintathu zamaseli ekhoni (trichromacy). Ezinye izilwane zingase zibe nenani elihlukile lezinhlobo zamangqamuzana e-cone noma zibe namehlo azwelayo kumaza amaza ahlukene, njengezinyosi ezikwazi ukuhlukanisa i-ultraviolet, ngaleyo ndlela zibe nebanga elihlukile lokuzwela umbala. Umbono wezilwane wombala usuka kubude obuhlukene bokukhanya noma ukuzwela kwe-spectral ezinhlotsheni zamaseli e-cone, abese ecutshungulwa ubuchopho.