  We present synthetic broad-band photometric colors of a late-type giant
located close to the RGB tip (T_eff = 3640 K, log g = 1.0 and [M/H] = 0.0).
Johnson-Cousins-Glass BVRIJHK colors were obtained from the spectral energy
distributions calculated using 3D hydrodynamical and 1D classical stellar
atmosphere models. The differences between photometric magnitudes and colors
predicted by the two types of models are significant, especially at optical
wavelengths where they may reach, e.g., \Delta V~0.16, \Delta R~0.13 and \Delta
(V-I)~0.14, \Delta (V-K)~0.20. Differences in the near-infrared are smaller but
still non-negligible (e.g., \Delta K~0.04). Such discrepancies may lead to
noticeably different photometric parameters when these are inferred from
photometry (e.g., effective temperature will change by \Delta T_eff~60 K due to
difference of \Delta (V-K)~0.20).
