All definitions of perception, cognition, and matter exist within the river of time. The Threshold of Residual Light explores how the very foundation of our perception undergoes profound transformations with the evolution of epochal tools and technology, through the changing symbolism of the color white. Engaging in a repeated dialogue with an AI, Kou Tak-Leong challenges, questions, and demands corrections, forcing it to negotiate between the warm white defined by human sensibility throughout history, and the cool white of modernity. This process of human-machine dialectic yields a multitude of "whites", condensed onto this 2.5-meter-long, slender light strip. No longer a simple color display, the light strip forms an abstract cross-section of a moment in the river of time, with each segment carrying the perceptual definition of a different era. The optical film applied to the device restricts the viewing angle, so that each moving viewer can only glimpse the "white segment" exclusive to their own position, unable to simultaneously see the visual state observed by others nearby. This "monologue in a public space" mirrors the contemporary individual's condition—intensely connected by digital technology yet simultaneously fragmented. 一切感知與物質皆隨時間流動，我們的世界並非由固定真理構成，而是由不斷累積的經驗所形塑。本裝置以「白色」為核心，探討感知如何隨著時代、工具與技術更迭而轉變。從神話中溫暖的創世光，到中世紀象徵潔淨的石灰白，再到現代AI所生成的冷調數據白，每種白都承載著不同時代的認知。作品透過人機對話捕捉這種流動的「白」，並以2.5米的光帶呈現，冷暖交錯、視覺游移，暗示過往記憶與現代數據在感官中交疊。裝置中的光學膜讓每位觀者僅能窺見專屬片段，映照出當代科技時代中被分眾化的個體感知，邀請觀者體驗感知的流動與多重現實。