Completely removing part of an image?

[Bob Hawkins]

I have isolated a person in a photograph using a combination of Magic Wand and Eraser. I notice, when I open the resulting .png file in another application, such as Paint, where the background is black, that there are numerous tiny bits that I have missed. This is mainly due to the confusing nature of the grey/white chequerboard, even when I am at 800% zoom, say. Is there any method that I can employ to ensure no such bits are left behind?

I notice, too, when using the eraser, that it might take two or three clicks to obtain a completely white square. I do not understand what this is about. Is this supposed to happen? Even more problematical is knowing when part of a greyish background over a grey chequerboard square has been completely erased.

[Sarkut]

Have a black (or other contrasting color) layer as the lowest layer.

Do your work above that layer.

Set the Eraser tool to Antialiasing Disabled.

[mountnman]

you can also use feather or a blur to smooth out such leftover pixels and make it blend well

[Bob Hawkins]

Sarkut

Many thanks - perfect!

[Bob Hawkins]

mountnman

Thanks - I'll experiment with them, too.

[ventor1]

Bob,

This sums up approx. 90% of what I do on PDN (assuming the threshold method doesn't give me the desired result), and I always follow these procedures:

1. Once I open up the image I create a new layer, send it to the bottom and with the paint bucket I make it blue.

2. Select the top layer (image) and use the magic wand at a low tolerance to remove most of the image background.

3. Use the eraser with antialiasing disabled to clean up any junk pixels.

4. Use the line tool (color set to same blue as background) to draw curves around object. Use control points to adjust curves as desired and then magic wand to delete curves.

5. Finish off the image edges with feather... and on the odd occasion I find myself using smart blur.

Edited December 9, 2010 by ventor1