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channel selection size changes when I select and apply layer mask


soultrippa

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I'll try and explain so this makes sense! I am making selections of models off of a white background. I use the quick select tool and refine to make a clean selection. I go in and use the clone tool to remove the "halo" that is still there to make a super clean selection with no light bleed on the model. I put a black layer underneath to make sure that I got all of the remnants. I save the selection and turn it into a channel. I apply the layer mask and everything looks good. I flatten the image and put it on a white background (this is the desired form of delivery for client) Image saved and closed. When reopened, I make a selection using the channel and there is a distinct halo effect still present. I have tried making the selection and going over it a couple times with the brush at 100% and it helps a little bit, but not entirely. Is there a way to eliminate this? I have already spent a lot of time going through cloning things out so it looks good, delivering the images, then they are sent back because of the halo. Not sure what else to do! Thanks for any help.Screen Shot 2013-06-28 at 5.37.11 PM.pngScreen Shot 2013-06-28 at 5.39.57 PM.png
 

Tom Mann

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I'll be back at my Photoshop computer in about two hours and I will have a look at it then.

Thank you for posting it.


Tom.
 

IamSam

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Hey soultrippa, I've been experimenting with your PSD. Here's what worked for me.

I used an alpha channel mask to remove the white BG of the image you flattened or merged with the white layer.

With the white BG removed, I command + clicked it's thumbnail to make a selection.

I went to SELECT > REFINE EDGE and made the following inputs. (call it selection 1)

Screen Shot 2013-06-28 at 9.56.18 PM.png

When done I duplicated this layer. (call it selection 2) I then added a new layer below this new one and filled it with white.
I highlighted the selection 2 layer and I then hit command + E to merge down.

Next, I command + clicked the selection 1 layer, (selection 2 is still highlighted) and hit he add layer mask icon at the bottom of the layers panel.

This is how it looks now.

Navy_Model_1.png
 

soultrippa

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Wow- thanks for going through the effort to help. Unfortunately, the final image has to have the type of edge that is seen in the first image I posted. I'm thinking it just might not be possible to make a ultra clean selection after I have flattened it.
 

Tom Mann

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I took a very simple approach:

1. Control-clicked on your layer mask to turn it into a selection.

2. Select / modify / contract that selection by 8 pixels.

3. Invert the selection.

4. With the layer mask selected, flood fill the new selection with black. This is just a quick way to enlarge the area hidden by the mask.

5. With the new layer mask still selected, right click on it and select, "Apply Layer Mask". This gives the client the subject on a transparent background so they can put whatever background they want under it.


The above method is a bit ham-handed for my taste in that if the edges involved were more complicated (eg, fine individual strands of hair), it would erode them and make the selection look very crude, but for the simple edges in this example, it quickly gets the job done. At 8 pixels of contraction, there is still a tiny bit of lightening near the edge. If you want absolutely no lightening near the edge, increase this to 9 or 10 px.

The real question is what causes the lightened edge. My guess is that the photographer blew out the background more than necessary, probably around 2 or 3 stops over, and a tiny bit of lens flare present caused the spill-over into the darker areas of the image. If this were me and I had a say in the photography, I would ask that future images be shot with the background not actually overexposed -- just bright, ie, say 250,250,250.

1a-layer_stack.jpg 1b-18200B_Navy_Model_3-4_054-tjm01b_cropped-01_white_bkgnd.jpg 1c-18200B_Navy_Model_3-4_054-tjm01b_cropped-02_black_bkgnd.jpg

HTH,

Tom

PS - Note: I put some keylines around my cropped images so that the white and black areas of the image could easily be distinguished from the white background used in forum posts.
 

soultrippa

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Thanks again for your input. Unfortunately the photography part is out of my sphere. It's not a ton of wrap around light, just enough to have to deal with and notice if it is not.
 

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