What source emits the most illumination?

Illumination is measured in lumens, which indicate the total amount of visible light emitted by a source. A light source with 10 watts and 4000 lumens emits more illumination than other options with lower lumens. Lumens are a direct measure of light output, so a higher lumen value corresponds to greater illumination. Axis product guides and technical references on lighting confirm that 4000 lumens provide the highest illumination among the given options.