Try this:
1) Place the bust on a layer on it’s own and close-cut it. Name the layer "bust"
2) Duplicate the layer, name the duplicate "halo"
3) Hide the "bust" layer
4) Locking the transparency of the "halo" layer, colour it black. You should now have a black shape that matches the shape of your image.
5) Unlock the transparency of the "halo" layer and apply a Gaussian blur (play with the settings until you get a result you like)
6) Unhide the "bust" layer you should now have a picture of the bust with a black halo.
Play with the opacity of the "halo" layer
Rene,
Thank you for taking the time to respond to my question on the Adobe Forum. I tried the method you suggested and the result was quite nice, I can see where I could use this technique in other areas, however it wasnt the exact effect I was after. The halo is a little too subtle even using a small pixel radius.
Its a long story but Im using this image to make a watermark, not the digital kind but the real thing in paper (I make paper by hand). A significant but small halo improves the watermark by setting it off against the surrounding paper. If the halo becomes too large it starts to look like a halo around a deity but if its small it makes the watermark pop off the page. Again, to complicate matters I need to create a white halo adjacent dark areas and a dark halo adjacent light areas. This could be accomplished in two steps using the same technique and then I would have to touch up the transitional areas.
So what Im after on half the bust is a small glow from dark (~90% grey) to 33% grey or 90% grey to transparent. Ive looked at other methods such as the paintbrush but the gradient has to remain perpendicular to the edge, which is always changing directions. I believe the answer still lies in capturing the offset pixels and manipulating them but Im still stumped as how to do that. I appreciate any thoughts you may have.
Brian
I think playing with the opacity of the "halo" layer should allow you to adjust how much the watermark "pops" off the page.
You can also try painting in dark grey instead of black in step 4
AFAIK, there is no way to take edge pixels alone and manipulate them the way you intend.
Again, to complicate matters I need to create a white halo adjacent dark areas and a dark halo adjacent light areas.
Try this: in step 4, instead of painting in black, try desaturating the halo layer and inverting the colour, then apply the Gaussien blur. You may also want to play with the contrast of the inverted image before doing the blur.
Another thing to try is playing with Levels or Curves on the halo.
