Unwanted layer mask bleedthrough

[weglian]

Disclaimer: I am new to Photoshop.

What I am trying to do: remove the background from my subject. So, I am using the object selection tool to grab the subject (a member of the marching band). That does a decent job, but I need to remove some of the background that peaks through holes in the instrument he is holding and then his hair is all over the place. So, I then try to use the lasso and or magic want to add or remove the bits I don't want. When I apply the mask some of what I kept has the background bleeeding through and some of what I deleted is still showing. From trying to find help on this, it appears that this will happen if you use a brush that is not black or white to paint the mask. But I'm not using any brush at all. Just the lasso and magic want to add/subtract from the mask edges.

There are hints of the hair at the top left of center and to the right and there is blue bleeding through on the left. I'm not painting anything, so I don't know how to fix this.

[weglian]

Well, I figured out a work around. Just add or remove the same area over and over again with the lasso tool. After doing that 4-5 times at the very same spot, there is no more bleed through (in either direction).

[Bojan Živković]

If you have a layer mask, paint with a white brush on the areas where you want to reveal hidden details, and use black paint on the areas where you want to hide details. Sometimes, you can use the selection tool to create a selection and then fill the mask with either black or white. Other times, you will need to adjust the brush size.

[weglian]

Disclaimer: This was my first real use of Photoshop. I keep seeing things about using a black or white brush. When I tried to use a brush, it would give me the circle with slash telling me it wasn't allowed. And I can't imagine trying to use a paint brush to do what I was trying to do, anyway. I just wanted to select the person and throw away everything else. Something was making my selections of what I include and not include be semi-transparent or something. Anyway, the solution was to add or reject the selection more than once and then it must have had the effect of painting with a black (white?) brush.

[davescm]

Can you repost the top pic without the 'marching ant' lines. Select and mask refine edge, followed by decontaminate (using a separate colour layer not the decontaminate button) should work.
Dave

[weglian]

I am so new to photoshop that I don't even understand anything you said. 🙂 I haven't found the decontaminate button or option.

What I was trying to do was the same as the option it was giving me to "Remove Background," but I wanted to have a little more control that what it was doing with that. So, I wanted everything in the marching ant lines and nothing outside of it. I didn't want to use a brush (and it wouldn't let me anyway for some reason). I just wanted to make my selection and keep the inside. I found that if I repeat my laso selection to add or remove from the selection over and over again, it did what I wanted it to do.