The Ghost Leaf

Experimental Procedure

1. Configure Parameters: Select a starting silhouette preset. The classic Magenta Leaf produces an emerald-green phantom, while Yellow yields a deep blue afterimage and Cyan produces a rich red. You can also slide the custom spectrum hue to generate any wavelength sequence.
2. Prepare Visual Field: Adjust the background. A neutral 18% gray is recommended as it helps stabilize afterimages by providing mild baseline photon stimulation to the recovering cones.
3. Initiate Test: Click the "Start Gaze Phase" button. The visual chamber will dim to your selected background configuration.
4. Lock Your Gaze: Direct your eyes to the central white target dot inside the leaf. Do not let your eyes drift. Keeping your visual coordinates perfectly static is vital, as even tiny saccadic eye movements redistribute the light across neighboring healthy receptors, weakening the bleaching effect.
5. Observe the Transformation: When the 15-second countdown ends, the leaf will vanish. Keep staring at the central target. Within fractions of a second, a vivid green phantom leaf will crystallize. Avoid rapid blinking to maintain the afterimage.

System Execution & Biophysical Mathematics

The localized photopigment bleaching is governed by a first-order differential decay model computed in real-time in the rendering loop. Let $S_{L,M,S}$ represent the relative physiological sensitivity of the L, M, and S-cone populations inside the macular boundary of the leaf projection:

during exposure:     dS_i / dt = -k_bleach * I_i * S_i
during recovery:     dS_i / dt = k_recovery * (1.0 - S_i)

Where $I_i \in [0, 1.0]$ is the normalized excitation coefficient of the color channels (Red, Green, Blue) corresponding to the stimulus, $k_{bleach} \approx 1.9 / \text{Duration}$ (ensuring a target depletion down to ~15% at completion), and $k_{recovery} \approx 0.05$ per second.

Technical Notes & Architecture Decisions:

• Retina Foveal Simulation: The dashboard canvas renders a procedural 2D packing array of 160 photoreceptors based on Fermat's spiral (using the golden angle $137.5^\circ$). Points are mapped inside the analytical boundary of the pointed leaf using the geometric envelope formula $|x| < 0.55 \cdot \cos(y \cdot \pi / 1.8)$ to selectively trigger bleaching animations.
• Web Audio API Integration: To heighten sensory pacing and scientific focus, a dual sine-wave oscillator is initialized upon gaze activation (180Hz and 182Hz to create a slight binaural focus beat) and swept exponentially to 220Hz. Upon transition, a resonant decay chime triggers at 660Hz to mark the blanking phase.
• Inactivity Demo Loop: A lightweight automated tutorial loop mimics gaze interaction after 25 seconds of idle behavior to assist new users in understanding the flow.

Visual Research Roadmap

• Saccadic Drift Modeling: Incorporate mouse or eye-tracking interfaces to shift the bleached retinal coordinates in real-time, simulating how natural ocular drift degrades or splits visual afterimages.
• HDR Display Scaling: Leverage modern High Dynamic Range (HDR) browser canvas APIs to significantly increase the peak luminance of the stimulus silhouette, drastically speeding up photochemical bleaching and intensifying the resulting phantom afterimage on supported screens.
• Spatial Frequency Grating: Integrate dynamic Gabor gratings to test how spatial details influence the sharpness and structure of manufactured afterimages in the visual cortex.