I’ve done a series of trials with CSS blur, brightness and hue‑rotate stacked on the same element. Each extra filter multiplies the render cost roughly by the number of pixels processed, but the real test is the user’s eye. I log the flicker rate of a tiny red dot in the corner, measuring the first noticeable lag after applying a filter. When I added a 0.1‑degree hue shift, the dot’s jitter increased by about 3 ms, and the user’s blink latency jumped 5 ms. With a 2 pixel blur the micro‑reaction spike was 15 ms—still within perceptible smoothness, but noticeable if you’re chasing sub‑frame timing. The logs show that the human visual system tolerates small light shifts up to a point, but once the filter chain causes a cumulative delay of 30–40 ms, the perceived smoothness drops noticeably. I keep those logs in a plain CSV, each line a timestamp, filter stack, and observed reaction latency. It’s a puzzle of light and time, not a rulebook.