GIMP Version: 2.8.14
Operating System: Linux
GIMP Experience: Intermediate Level

List any relevant plug-ins or scripts:
Filters > Light and Shadow > Supernova

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Supernova

- I am having an issue with Supernova creating gradient 'rings' of color far out from the radius of the supernova
These are rings and not the rays.
They make the rest of the image i am working on blurry with the color of that supernova

here is an example from Asteroid City: The flare is tiny to make a beacon light, but there are rings farther out
How can i clear or minimize this yet still keep the rays when the supernova is larger

Thank you

Hi leftyleo! GIMP by default have an Image precision of 8 bit integer. Before you apply the Supernova filter, go to: Image> Precision, and change it to 32 bit integer to see if that work. Usually in 8 bit integer you will have the same effect if your blur anything in dark.

Good advice!
16 bit should be enough, with 32 bit he will get a huge sized file and might not even see the difference between 16 and 32



Another solution which is working well in 8 bit:
Your supernova is on its own layer (each supernova has its own layer, another advantage of this is it allows you to put your supernova behind your buildings)
Ellipse tool > make a circle around the supernova size you want to keep > then add a Mask from the selection > Be sure that the mask is selected > Then Filters/Blur/ Gaussian blur > blur a lot

(Selection is in the Channels, selection has feather edges ~25)

Pocholo and PixLab: Thank you for the responses

I understand the precision method. It does clear up the rings, even on the lower 16bit Int
and going up to 32bit might not be necessary in most cases for me, but i will keep it in mind.

Patrice: I understand about 95% of your example and tried it myself. Of course we will have some
variations but it worked great. The piece i didnt understand is why is the selection in the channels tab.
Specifically : "(Selection is in the Channels, selection has feather edges ~25)"

I do see the copy in the channels tab. I know you can switch color channels on/off
but to edit you have to go to the colors>curves. Is there something i need to adjust in channels
Or are you just using that to select the blue and not other colors?

Thank you for the reminder to use feather edges , i often forget to use it.
And now i understand the "Radius" slider under Feathered Edges .
(face palm) .. silly me on that one

The issue on this recently came up then i was trying a YouTube Glass Spheres tutorial
from one of the threads and one step was a white supernova that washed out the image.
I did some ellipses, fills, blurs, cuts, etc without using supernova and got a pretty
good result. Basics a great fall backs .

You don't need to have your selection saved in the Channels tab = nothing to adjust
It was just for you as an example -> IF you wanted to try out with that specific selection on the XCF I uploaded, that's all
(some time I give too much infos without explanations, like something which needs A->B->C, I give A straight to C, sorry about that )

So let's forget that selection in the Channels tab, like if it never existed and say that you understood 100%

OK (lol) thank you

@ @
\_/