Phase curves corresponding to photometric parameter combinations (b, B₀) that reproduce the same laboratory reflectance at the reference geometry (i₀, e₀, g₀) = (30^∘, 0^∘, 30^∘). The parameters are explored over −0.3 ≤ b ≤ 0.7 and 0 ≤ B₀ ≤ 3, while the single-scattering albedo and opposition-surge width are fixed at ω = 0.6 and h = 0.1, respectively. All solutions intersect at the measured phase angle g₀ = 30^∘ by construction but diverge away from the laboratory geometry, particularly toward small phase angles where opposition effects dominate. This demonstrates that identical laboratory reflectance measurements can correspond to substantially different angular scattering behavior.