Using Starnet++ for star reduction.

[ollypenrice]

Here are some experiments using Starnet++ as a star reduction tool. I started with this image, on which star control had always been difficult. This is as far as I could get with existing methods like star masking during the stretch and Noel's Actions.

It's still pretty 'busy' with stars so I ran it through Starnet and got this.

Clearly not satisfactory on its own but a start. The larger (damaged) stars I would replace at the end but the golden pair near the middle had leaked out their colour quite badly so, using the clone stamp set to colour, I just reddened the golden spread.

I then made a three layer stack with the original on the top and the bottom with the starless version between them. I set the top layer's blend mode to lighten and pulled down the curve as below, experimenting with different curve shapes to find the best looking stars. You could take the reduction considerably further but I like to work in small increments so I settled for this.

After flattening the top onto the starless I was left with those larger damaged stars. I simply erased them from the modified layer to restore the originals. Below we have before and after, before being on the right.

Remember that I was starting on an already star-reduced image so the difference isn't extreme.

Olly

 

Edited November 17, 2020 by ollypenrice

[geeklee]

Thanks @ollypenrice.  After reading this, I had to give it a go, so stepped outside PixInsight with my two TIFF files and tried to match the steps as close as I could with Affinity Photo.  This has really been an eye opener for one of the problems I occasionally have with Starnet - turning something natural looking out the other end primarily when there are a lot of "damaged" areas.  I chuckled with glee when it spoiled a bright part of a nebula but I just erased that from the middle layer and got my original back so easily.  It let me fix other bits too + check out what a reduced star version would like of course!

That ability (which is one of many often talked about big pros of PS type workflows) to maintain the changes and just readjust existing layers and masks is brilliant.  This has made me think differently about how I might try and do similar steps in PI too.

Thanks again for posting this. 

Edited November 17, 2020 by geeklee