When to Use Linear Fit

jeffrey merrill

Hi Adam:  

 I reviewed the linear fit videos..saw the utility of Linear Fit when blending Ha into either Luminance, or into Red channel, and reviewed your argument to not use linear fit to match red master to green master to blue master when combining into RGB image.

I was wondering whether there was a role in matching the L* channel of an RGB to the luminance before combing using the LRGBCombination tool into the LRGB image?

jeff

BlockHead

Hi Jeff,

It can be used in that way- but again (as you will likely encounter time and again) my techniques are "novel" is I think the word you used. I generally argue that simply "matching" a luminance with chrominance via Linear Fit isn't necessarily going to give you the best/most pleasing result. It can certainly get you in the ball park- I instead use a combination of other non-linear adjustments on the color image to better match the Luminance and give me a colorful result quickly. 

(Those that are familiar with my past techniques in Photoshop using Shadows/Highlights will appreciate this distinction.)

-the Blockhead