I've only had Affinity Designer for a few days. In the past, I've used Photoshop, although I'm not an expert. My favorite Adobe program was Fireworks, which has been discontinued.
I'm trying to do a very basic thing — set part of a photo to a heavy blur, but whatever I do, the Gaussian Blur seems to always affect the entire photo. (Yes, I could select part of my photo and add it to another Layer but, in the other programs I've used, there was always a quick way to only affect the part of the image which was Selected.)
In testing this, with a simple document, these are my Steps:
create new document
switch to Pixel Persona
select the Paint Brush Tool
set Width to 110px
set Flow to 100%
set Hardness to 100% (Steps 4, 5 and 6 are only to create a sharp image, so I can more easily see the results of the blurring effect.)
select a blue color
draw 5, horizontal strokes, each separated from the others
select the Rectangular Marquee
draw a selection down through all the strokes but leave parts of them unselected
select Effects from the right-side panel
put a Checkmark in Gaussian Blur
drag the Radius past 15px and "everything" is blurred. Why? Why isn't the blur only applied to the parts of the image "within" the Selection?
I see the same results if I use the Selection Brush Tool (or Rectangular Marquee).
If I select the Paint Brush Tool and draw across this page, it only paints within the Selection, which is what it's supposed to do. Why is Gaussian Blur ignoring the selected area?
Yes, I've tried using the Blur Brush Tool but, no matter how I adjust those Settings, it's effect is extremely weak.
I have watched a few Affinity Designer videos and searched this Forum but could not find an answer to this. I'm sure it's something very simple that I'm "doing" or "not doing".