How to add Luminance to RGB


New member
Mar 29, 2020
I am new to Pixinsight, when combining LRGB, it is advisable to leave the Luminance behind, otherwise, the image wont comes outright. Please can anyone give me a bit of guidance on how do I combine Luminance when finishing the image, or how to combine LRGB image?

Many thanks.



Well-known member
A crude description of my workflow is as follows.
Assuming you have the integrated masters: L, R, G; B
I crop the masters to exclude stacking artefacts. I make absolutely sure that the masters get cropped exactly the same. The masters were already aligned, because I use one and the same sub exposure during star alignment.
Then I combine R, G, B into an RGB image.
I use separate DBE processes on the RGB and on the L image
From that step on I process the RGB data for maximum colour punch. I don't care too much about detail. Eg no deconvolution. My stretching method of choice is arcsinh stretch, because it keeps colour balance. I also make sure that star colour is ok, and that stars don't grow too much during processing.
Next, I process the L image for maximum detail; deconvolution, stretching, hdr-transformation, etc
Finally I combine the L image with the RGB image using LRGB-combination (only check L) applied to the RGB image.
I then continue with tweaking contrast and saturation.

Hope this helps