The balance point of the blue hour: The ten minutes when indoor and outdoor brightness are equal

The exterior of a building approximately twenty minutes after sunset, when the sky is a saturated deep blue, and the brightness of the indoor artificial lighting is precisely equivalent to the sky's brightness. At this moment, the building's exterior wall materials can still reveal their color and texture under the lingering twilight, and the indoor light can just penetrate without being overexposed. The glass is neither a black mirror nor brightly white, but clearly shows the spatial depth of the interior. The building's silhouette, materials, and indoor activities are simultaneously visible, making it the most information-rich moment of the day. The ground and surrounding environment still retain a faint twilight. Avoid: depicting the sky as completely black or still bright daylight, allowing indoor light to overexpose into white blocks, eliminating material details of the exterior walls, adding strong external floodlighting.

Translated from Chinese by AI.

日落後約二十分鐘的建築外觀,天空呈現飽和的深藍,而室內人工照明的亮度恰好與天空亮度相當。此時建築的外牆材料仍能被殘存的天光照出顏色與質感,室內的光也剛好能透出而不至於過曝,玻璃既不是黑鏡也不是白亮,而是清楚地看見室內的空間深度。建築的輪廓、材料、室內活動同時可見,是一天中資訊量最完整的時刻。地面與周邊環境仍保有微弱的天光。避免:把天空畫成全黑或仍然明亮的日光、讓室內光過曝成白塊、消除外牆的材料細節、加入強烈的外部投光。