Bloom R ,G, B,

Surface bloom is a near‑specular scattering effect that appears as a loss of reflective contrast in a mirror‑like surface and can include a subtle colour shift that is not detected by conventional monochromatic haze meters. Standard haze meters use a light source and detector combination filtered to the photopic V(λ) response of the human eye, producing a single luminance‑weighted signal, so wavelength‑dependent scattering can be visually apparent yet remain largely undetected in the measured haze value.

To detect this phenomenon, the Aesthtix instrument uses an unfiltered white LED arranged as a 10‑degree spotlight and an RGB camera, analysing the near‑specular region of the reflected image. The bloom is quantified independently in each colour channel as a normalised ratio of the bloom signal to a calibrated specular reference signal, and the spatial extent of the bloom in each channel is reported as an area in (\text{mm}^2). The red, green and blue bloom indices are defined as:

[
B_{R} = \frac{S_{\text{bloom},R}}{S_{\text{spec},R}}
]

[
B_{G} = \frac{S_{\text{bloom},G}}{S_{\text{spec},G}}
]

[
B_{B} = \frac{S_{\text{bloom},B}}{S_{\text{spec},B}}
]

where (B_{R}, B_{G}, B_{B}) are the dimensionless bloom values for the red, green and blue channels, (S_{\text{bloom},R/G/B}) are the measured near‑specular bloom signals, and (S_{\text{spec},R/G/B}) are the corresponding calibrated specular signals used for normalisation. For each channel, the bloom size (area of the near‑specular scattering region exceeding a defined threshold) is calculated in (\text{mm}^2), providing both an intensity‑based metric ((B_{R/G/B})) and a geometric metric (bloom area) to characterise the magnitude and chromatic character of surface bloom.