in photography I like when the object is focused and sharp but everything else is blurred. But how do I get the background blurred but also see a depth, so how can I paint the nearer part and the part further away, although both being blurred?
Also with saturation like perspective without blur?
For a new image that you’ve just started working on, you can structure the layers so that you have ‘foreground’, ‘middle ground’ and ‘background’ (or even more different depths if you like).
Then you can paint them ‘normally’ and afterwards add a blur and desaturation filters then adjust the amount of blur and desaturation to get an effect that works well.
For an existing image or even a photograph with a small aperture that has given a deep depth of field, you can use the selection tools (with local selection masks) to isolate foreground, middle ground and background and then apply the filters.
It’s helpful to put feathering on the selections to avoid sudden transitions of blur and desaturation amount.
I would draw the background in low detail and then apply a blur filter mask to it. That’s how I did it in the past.
However I find that for myself at least blur for paintings doesn’t really work like it does for photos. So unless I go for a camera effect on purpose I try to avoid all the typical lens effects like blur, flare or chromatic aberration. I stick with the low detail however, similar to how games do it wit LOD models, to guide the viewer.
Guess it depends a lot on the painting style. For more realistic, blur might work better.