Strange (?) Invert Selection result

[OldNick]

I have a photo of a flower, a simple jpg with no layers etc. Just the straight shot. I was trying out darkening just the background. I selected the flower mostly with the Magic Wand and then with freehand just circled a few bits that were missed.

The result is as you can see in Before Invert.jpg. To me the flower looks totally selected.

When I Invert Selection, a lot of the flower is included in the inversion, as shown in After Invert.jpg.

I used to do quite a bit of this sort of stuff and I do not remember this happening.

I realise I can remove the stuff I do not want from the inversion, but for all of me the inversion should include none of the flower.

Any help appreciated.

[JoeB]

That means that you hadn't actually selected all of the pixels within the flower before doing the invert. It just looked like you had because the unselected areas were too small to see at the magnification/zoom level you were viewing it at.

[OldNick]

OK. Thanks. That makes sense, but....

So how come they _are_ suddenly big enough to see when they are inverted? I guess feathering might explain it. But I am only feathering by 6 pixels on a full-sized 5200*3500 image.

I just zoomed in the 50%, then did some selecting. It _still_ looked as if it was all selected, but when I inverted, quite large chunks changed.

[hartpaul]

They are big enough to see when inverted because the marquee / marching ants surrounds even a couple of pixels with a feathered amount and as well you see something moving which attracts the eye more easily.

Before you invert you might go to your Layers Palette an click the 4th button Edit Selection or Selections > Edit Selection.

You will see that all the selected area becomes red with a mask overlay.
Move to the paintbrush and select white as the color , zoom in and anything not red should be painted to include in the selection.
If you were selecting a subject that was the same red color as the mask overlay it might be difficult to see any areas not covered, just select that Mask layer in the Layers and right click and choose Properties. Here you can change the color of that mask so that it is say green and then any red parts of the flower not selected will be very obvious.

[OldNick]

Thank you very much for taking so much effort over this. I tried what you said with the brush and even at huge zoom nothing showed. Same for the mask.

I then tried selecting with zero feather and that solved it. I would have sworn the inverted selection bits that appeared were more than 12 pixels wide. In some cases I can only think that 1 pixel only, or a strip 1 pixel wide, was missed they, are so impossible to see.

I used to use feathered selections a lot. I need to get back into Modifying selections and feathering after the fact and see what happens. If that's a workaround, that may be why I do not remember this problem as a problem.

[OldNick]

I selected the flower with 0 feather, using the Magic Brush. When I inverted there was no strangeness. I then Modified and Inside/Outside Feathered the inverted selection and the result was exactly as I wanted.

Thanks again for talking through this with me.