Because raw data is "linear," it looks nearly black to the human eye.
Standard processing in PixInsight follows a specific path regarding the STF link: pixinsight lerar link
In the Screen Transfer Function (STF) , the button (represented by a small chain icon in the top left of the STF window) determines how PixInsight calculates an automatic stretch for your image. Because raw data is "linear," it looks nearly
PixInsight applies the same mathematical stretch to all three color channels (Red, Green, and Blue) based on the image's overall statistics. PixInsight stretches the channels separately
Perform processes like SpectrophotometricColorCalibration (SPCC) or BackgroundNeutralization .
When you use an Unlinked STF (Ctrl + Click the "Radioactive" icon), PixInsight stretches the channels separately, which removes that heavy green or red cast and lets you see the actual nebula or galaxy detail. The Workflow: When to Toggle the Link
Raw astronomical data often has a heavy color bias, frequently appearing green due to the Bayer pattern of color cameras or atmospheric conditions.