channel mask-I need some advices

[giorgi]

Hi all.
I'm trying to learn channel masking technique and below you can see my not so successful attempt. I changed background with the night sky image. I think I made good mask but as you can see there are some whites around the trees. this is where I got stuck. this isn't look clean and I have to know how to fix this. I thought that feather and shift edges would work but they don't.
So, I was wondering if you have any idea to do in this situation to make more realistic look.

 

[thebestcpu]

HI @giorgi
It might help forum members to help you if the details of you workflow is described step by step. Channels can be used in a lot of ways for masking so it may not be obvious which way you used.
Just a suggestion
John Wheeler

 

[giorgi]

help you if the details of you workflow is described step by step

OK I will try. on the forest's image I go to channels panel and select BLUE from RGB layers cb that had most contrast. dublicate it and add some levels for more difference between black and white. also I used brush tool on some parts of the image(mostly at the bottom of the image). clicked select, invert selection and made layer mask. that was whole process

Thanks for your interest.

 

[IamSam]

dublicate it and add some levels for more difference between black and white.

In this step, you really need to have complete black and white. Can you post a screenshot of the "duplicated blue channel" after you applied the levels adjustment?

Also, does the original forest image have a light or bright sky? I'm assuming it does.

Did you try to defringe or remove white matte?

 

[giorgi]

Can you post a screenshot of the "duplicated blue channel" after you applied the levels adjustment?

does the original forest image have a light or bright sky?

it does.

Did you try to defringe or remove white matte?

no i did't and I am going to try thank you

 

[giorgi]

guys I think I found a solution and I am going to share it with you bc it may help someone in the future. on the layers panel i secelted "layer mask trumbnail" then choose brush tool. brush mode set to "Overlay", hardness to zero and opacity 100% but then realise 60%-70% is better. and also you must choose black color. I used this brush and i think brush size doesn't matter in this case so it gave me this result which is better than last one. not perfect but better. anyway I appretiate your replies I learn something from it and I am gonna say big thank for your attention.

 

[IamSam]

Alpha Channel Masking.

How to mask hair in Photoshop.

Masking with channels.

Using channel to make better selections in Adobe Photoshop.

ADVANCED Hair selection - Masking hair in Photoshop.