Mark, Thank you for ArcsinhStretch! It will be detailed in my book's second edition. Afredo/DLD, Mark explains the error well. But, in general, debayering must occur (not only before Drizzle, but) before alignment. The matrix's info has to be decoded before the transformation that occurs during registration- got it?! As Mark explains Drizzle, it's a bit mysterious to those of us 'not under the hood.' Debayer collects the matrix offset info to pass on to StarAlignment, which generates the Drizzle files. ImgInt then updates these xdrz files for DrizzleIntegration. This took me a bit to get too! Yes, the Debayer process is used in the proper sequence, but as you say, it's DI that produces the final, uninterpolated color image. The good news is, OSC/CFA Drizzle is now easier than ever with either BPP or the manual track.