Difference, Δ = m_synth − m_cat, versus color index, color_bv = (B − V), for everything identified in APPLAUSE DR3 that was cleaned and matched with Gaia DR3 stars. Left: plate 12368, Großer Schmidt-Spiegel, Hamburg Observatory, 12 Dec 1968, Kodak IIa-O with filter GG13(=385), scan 14850, color term 0.83. Right: plate 11626, Großer Schmidt-Spiegel, Hamburg Observatory, 5 Oct 1964, Kodak 103a-D with filter GG11, scan 14057, and color term 0.01. We used an air mass of 1.25 for the analysis in both cases. These plates in APPLAUSE have two scanned files with different color terms, producing two distributions. To keep this analysis figure simple, only one distribution for each such plate is shown.