We present synthetic broad-band photometric colors of a late-type giant located close to the RGB tip ( T _ { eff } \approx 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 \approx 0.16 , \Delta R \approx 0.13 and \Delta ( V - I ) \approx 0.14 , \Delta ( V - K ) \approx 0.20 .
Differences in the near-infrared are smaller but still non-negligible ( e.g. , \Delta K \approx 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 } \approx 60 K due to difference of \Delta ( V - K ) \approx 0.20 ) .