I'm a photographer with intermediate PS skills retouching my own work. I want to apply the healing brush tool next to a prominent change in tone, texture and color. Normally, the healing brush at its destination samples a few pixels beyond its cursor edge and blends tone, texture and color for a smooth result. But I want to retouch skin that is right next to underwear without the destination cursor seeing beyond its edge and contaminating the skin with the underwear colors and tone.

With the Stamp Tool I just make a selection and the cloning is restricted to within the selection. The healing brush, an otherwise better tool for my purposes, doesn't work this way and at the selection edges it still looks beyond its cursor edge and incorporates those colors and tones as it paints.

I found a reference in a book to using a selection to constrain the healing brush, which I couldn't make work, and when I wrote the author about it he said I needed to modify the selection and reduce it by 1-5 pixels and it would work okay. I tried that and still can't make it work.

I'm using a healing brush with 100% hardness with normal mode, no pattern.

What am I doing wrong, how do I constrain the healing brush from contamination from outside a selection? Thanks very much.

I find it better to use the clone stamp close to the edge of something, plenty of ways to get that
spot to match tone and texture of surrounding area.

1. I am not in front of computer so I cannot be very specific but there is a setting for the brush size to show the actual working border. Try to find that.

2. Make sure your brush is of similar size to what you are healing.

3. The healing brush doesn't work well on border areas because it is based on internal frequency separation which PS does inside the brush area. So cloning is a better choice. Or you have to be very skillful in not touching adjacent zones which may cause tone bleeding.

4. Hard selection does work if made properly.

Thanks everyone, very helpful.