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Help me fix this problem please on channel masking


balavalli

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Hi Gurus today am trying to cut an image from its white background using channels .Everything goes well.But when am working on it i see a small lines around the image which are being created while am masking it with the brush tool and its creating a hallow white borders around the final product. Please help me fix this problem please ? Explain em and teach me how to deal with these incidents.i always come to here when i got struck some thing on Photoshop.Thanks in advance and i attached the images.

ps.jpg

As a result this is the out put

output.jpg
 

IamSam

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You can't get these results using the Brush Tool. It's impossible unless you yourself are creating the thin black strip.

The channel must all black and all white. If you leave that small black strip all the way around, you will have the results your getting.

You must be using a different tool to make your selection.
 

IamSam

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This is my green channel copy.
Screen Shot 2016-01-19 at 12.08.40 AM.png

This is my green channel copy inverted using Cmd/Cntrl + I.
Screen Shot 2016-01-19 at 12.08.59 AM.png

This is my inverted green channel copy after about 3 to 5 minutes BRUSH TOOL work.
Notice I did not leave the black strip. (not stripe)
The bag is all white and the BG is all black.
Screen Shot 2016-01-19 at 12.19.00 AM.png

This is the bag after the channel selection with a black BG.
Screen Shot 2016-01-19 at 12.20.48 AM.png
 

balavalli

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ok sure
I selected an image which i want to remove the background of it.In this case the golf kit.
Then
1) i select the best channels which will have more contrast.In this case i found green is channel is the best.
2)Then i used levels option to make the golf kit to make it darker that differentiate from the white background.
3)Once i think its better i inverted the image
4)Then i choose the brush tool and set the blend mode to overlay and try to make the image black playing with the softness and hardness of the brushes ,here am getting a halo around the image as i attached in here in my earlier post above )

Callaway GBB Golf Bag.fw.png

This is the result

result.jpg
 
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Tom Mann

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I suspect the major problem you are having is simply that your brush work isn't accurate enough.

When it looks like too much fiddly, accurate brush work is required, a shortcut that I take is (using Sam's green channel image as an example) to use the Quick Selection tool on the almost completely black background to give you a hard edge. See the marching ants in the following screen capture:

01-result_of_quick_selection_tool.jpg

Then, use the Paint Bucket tool to fill the outside with black:

02-fill_outside_with_black.jpg

Next, invert the selection, fill the inside with white, and, except for a very minor amount of cleanup work, you have exactly the mask you need in seconds:

03-invert_mask_fill_inside_with_white.jpg


HTH,

Tom M
 

IamSam

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Here's one of your problems.

balavali said:
4)Then i choose the brush tool and set the blend mode to overlay and try to make the image black playing with
Set your brush to NORMAL blend mode. Set your opacity to 100% and your flow to 100%. Set your spacing to 1% and set your brushes hardness to 85%.

For me personally and with what I have experienced in the past when working with channel selections, I won't ever use the Magic Wand or the Quick selection tools. They leave behind edge remnants that you have to go back and clean up. But they will work in a pinch!

For example. This is a selection made with the Quick Selection Tool.
Notice the white remnant? This of course can be removed using refine mask.
It also left out one part of the bag and left in the shadow at the base of the stand.
Screen Shot 2016-01-19 at 10.56.03 AM.png

Here is the same area using the Brush, Dodge, Burn, tools.
Screen Shot 2016-01-19 at 10.56.32 AM.png

Any of the other selection tools work better like the Pen Tool or the Polygonal Lasso Tool. I mainly only use the Brush Tool and the Dodge and Burn tools when working on channel masking.
 
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