Dive into STF: What the Heck is the Screen Transfer Function Even Doing?

There seems to be some confusion, especially around beginners as to what the STF is and isn't doing in PixInsight (hint, it is doing nothing to your image!). Let's figure out why after NoiseXterminator your STF goes all crazy, what that means and why you should stop worrying what the STF is showing you.
If you want to check out my beta version of my new Statistical Stretch script you can find it at the bottom of my PJSR scripts page: www.setiastro.com/pjsr-scripts
Please leave any questions or comments!!

[@carlburton3900]

Thx for doing this, you explained what happens to the image during processing and what the STF is doing.
I tried your stretching script and the setting I used was .13, then execute 3 times until happy with the stretch. I'll run more and let you know.
Great video, I'm glad someone does the math.

[@bosseblomqvist2272]

Still learning Pixinsight and this was very helpful, thanks!

[@setiv2]

There is a lot in pixinsight. I have some full pixinsight walk throughs that I made too which may help. Keep at it!

[@AmatureAstronomer]

Informative.

[@JeffHorne]

I’ll be installing this script! Thank you for the explanation, as well as the script. My main takeaway is that one should probably be selective with what gets used before a permanent STF. Maybe stick to gradient removal, color calibration, BlurX, and processes like that, before doing any STF.

[@setiv2]

I flick stf off and on all the time. Just really good to understand what it is showing and not freaking out. I had a couple extra mouse buttons on my computer mouse and mapped one of them to ctrl+a and the other to ctrl+F12. That lets me flick stf on and off witha mouse press