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Background coming through foreground picture

Posted: Fri, 28th Jan 2011, 6:54pm

Post 1 of 8

FXhomer90125

Force: 100 | Joined: 19th Jan 2011 | Posts: 3

PhotoKey Lite User

Gold Member

I have no problems uploading my pictures and background into the program, but the background image is showing through my subjects. I took pictures of people dressed in black clothing (which is where I notice it the most)and tried using my own backdrop images I took of the outdoors. When I put in my background, white spots from the background show through on the clothing and other parts of the picture. I also tried using some of the background images that came with the program, but I am still having the same problem. Has anyone had this problem? Or does anyone have any ideas?
Posted: Fri, 28th Jan 2011, 6:59pm

Post 2 of 8

Axeman

Force: 17995 | Joined: 20th Jan 2002 | Posts: 6124

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SuperUser

Your key is removing portions of you subject, it has nothing to do with the background itself. There is green in the foreground image, and when it gets removed, its leaving holes in your subject, so the background shows through. Are you unable to correct it by adjusting the Key settings or using a mask? If not, the image may need re-shot so that the green isn't being reflected onto the subject. However, you can almost certainly fix this by proper adjustment of the various keying tools, or using masks to retain those areas.
Posted: Fri, 28th Jan 2011, 11:40pm

Post 3 of 8

FXhomer90125

Force: 100 | Joined: 19th Jan 2011 | Posts: 3

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thanks...i'll try your suggestions. My subjects weren't wearing green though. the background is coming through in a dot pattern even on the skin in some pics. i will play around with the settings some more. i am new to this and still learning. thanks again
Posted: Fri, 28th Jan 2011, 11:53pm

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Axeman

Force: 17995 | Joined: 20th Jan 2002 | Posts: 6124

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SuperUser

Even if they aren't wearing green, black has a tendency to reflect the color of the background, and that could be the cause. It trying my earlier suggestions doesn't solve it, please provide a link to one of the original greenscreen images, so we can try key it ourselves and offer more specific suggestions based on what you are dealing with.
Posted: Sat, 29th Jan 2011, 1:58am

Post 5 of 8

FXhomer90125

Force: 100 | Joined: 19th Jan 2011 | Posts: 3

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I'll try to work on the pictures some time this weekend and let you know how things turn out. Thanks for the sugguestions.
Posted: Fri, 4th Feb 2011, 3:40pm

Post 6 of 8

FXhomer136942

Force: 0 | Joined: 4th Feb 2011 | Posts: 2

Member

[quote="Axeman"]Even if they aren't wearing green, black has a tendency to reflect the color of the background, and that could be the cause. It trying my earlier suggestions doesn't solve it, please provide a link to one of the original greenscreen images, so we can try key it ourselves and offer more specific suggestions based on what you are dealing with.[/quote]
Posted: Fri, 4th Feb 2011, 3:41pm

Post 7 of 8

FXhomer136942

Force: 0 | Joined: 4th Feb 2011 | Posts: 2

Member

Axeman wrote:

Your key is removing portions of you subject, it has nothing to do with the background itself. There is green in the foreground image, and when it gets removed, its leaving holes in your subject, so the background shows through. Are you unable to correct it by adjusting the Key settings or using a mask? If not, the image may need re-shot so that the green isn't being reflected onto the subject. However, you can almost certainly fix this by proper adjustment of the various keying tools, or using masks to retain those areas.
Posted: Sat, 5th Feb 2011, 4:38am

Post 8 of 8

njush

Force: 1720 | Joined: 29th Jan 2010 | Posts: 46

PhotoKey 3 User Windows User MacOS User

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This is a previously reported issue.
From what I can tell, PK is technically "working", but lacks a control that would allow pixels to be ignored by keying based on brightness values.

Color difference keying works by creating transparency in pixels where the RGB color channel matching the screen color has a value greater than the other two channels. The thing is, for shades of black, it's really easy for the green channel to be slightly higher than red or blue (and therefore at least partially transparent) even though the pixel is significantly darker than any pixels on the screen itself.

Here's a thread where this was previously discussed (though I'm just now noticing the request for posting original images at the end of the thread. I'll have to see if I can find some....):
https://fxhome.com/forums/viewtopic.php?t=43149