Blur filter layers in CS2 (am I going mad?)

[coldpenguin]

I am sure in the past, I could create a filter layer in CS2.

I.e., I had an image, I created an adjustment layer and selected to desaturate an area.
I then thought that I could create another layer, and apply a gaussian blur to an area of the image. By being an adjustment layer, I could later on decide to move or modify the layer.

However, the last time I tried, I couldn't work out how to do this. Am I going mad, could someone tell me whether I dreamt this capability, or if not, how I do it?

 

[swanseamale47]

You can't blur an "empty" layer, you actually need something to blur, it's often a duplicate layer with the blend mode changed to something else (overlay maybe) You can also blur a layer mask which you could return to later and ajust.
What exactly are you trying to achive?
There is smart filters is that what you mean?

 

[coldpenguin]

Maybe that is my problem.
Although I could have sworn I had done it in the past without the need to copy/paste or duplicate via copy.
The photo I was trying to edit previously, was somebody else's on here, so I won't show that.
However, here is a photo that shows a similar effect to what I was trying to do.


So, background layer is initial import.
I select the apple, and create a selection, apple
I select the leaf, and create a selection, leaf
I select both apple and leaf, and select->inverse.
I do layer, new adjustment layer, hue/saturation. I select saturation to be 0

Now, I want to blur the rest of the image. So I thought, in the past, I selected the inverse of apple and leaf, created a new layer from this, and then applied this layer as a blur filter layer. This layer is just a layer mask effectively, it doens't have any RGB pixels.

However, I have to at the moment, select apple+leaf, select inverse, edit->copy merged, paste as new layer, then filter->blur->gaussian.

Now, if I want to increase/decrease the number of leaves which are black and white, I can fill in/delete the adjustment layer, but if I want to increase/decrease the bluring, I have to go back to the background layer and re-copy.

I thought, in the past, that it was possible to create a layer, which was effectively like a filter in front of the lens/viewer

 

[swanseamale47]

Ahh I think I know what your getting at, I suspect what you did was create a new channel from the selection, then using blur/lens blur you can select the alpha channel as a source?.