Hello, I've been practicing with "the Vincent Paris" way of combining Hydrogen-Alpha with Red for (HaR)GB and am wondering whether or not one should perform a ColorCalibration run after the combination is done.
For example, below are three samples of M42 Orion Nebula.
The middle one shows the original RGB after combining the R, G and B monochrome images, performing a BackgroundNeutralization, ColorCalibration and SCNR (to remove the green tint). The left and right ones are the same image but after combining the Ha data with the R data to produce a new image. The following process was used:
((HA * 70) - (R * 7)) / (70 - 7) = "NewComb"
and
R + ((NewComb - Med(NewComb)) * 2.5) = "NewRed"
After the colour combination is done with the new red image, the background takes a more green-blue tone and so I perform another BackgroundNeutralization. This yields the image on the right. As a test though, if I then perform a ColorCalibration and SCNR (to remove the green tint), I get the image on the left. Unfortunately it seems that the image on the left looks FAR too much like the original RGB (no Ha data combined) and seems to show even less faint nebulosity. As a result, it feels as if performing a ColorCalibration on the combined image is not really the way forward, but without it the image seems a tad TOO red. I guess the "boosting factor" of 2.5 may be too high for taste in this instance but the question is simple: Should one perform a ColorCalibration after combining with Ha data?
