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Proper Lighting

Posted: Tue, 2nd Mar 2010, 12:21am

Post 1 of 4

FXhomer109748

Force: 0 | Joined: 2nd Mar 2010 | Posts: 1

Member

I will using FXHome Photokey2 lite for a big project at a high school in TWO days. When creating my displays from previous pictures, where I erased the original background and put it on a green background, those worked fine. Beautiful. But when running a last minute test on a live subject, I got some spill (even when using the highest setting on spill suppresion)and splotches of grey where the green did not totally disappear.

I've been told to move the subject further away from the background. I tried that at 5ft. away from background. It was still a slight problem. Also, on other shots taken(live), Some of the background came through. I realize that my problems are more than likely caused by incorrect lighting. what is the best light set up?

Humphrey
Posted: Tue, 2nd Mar 2010, 1:18am

Post 2 of 4

Axeman

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

VisionLab User VideoWrap User PhotoKey 5 Pro User MuzzlePlug User PowerPlug User PhotoKey 3 Plug-in User FXhome Movie Maker FXpreset Maker MacOS User

SuperUser

If you only have two days till your shoot, I recommend visiting TubeTape's Youtube channel for some suggestions:

http://www.youtube.com/watch?v=x34mnZwyoDI
http://www.youtube.com/watch?v=MbTISLBgDfk
http://www.youtube.com/watch?v=jXvXCTfin5E

Those are a few of their quick videos that might be helpful.
Posted: Tue, 2nd Mar 2010, 9:39am

Post 3 of 4

Simon K Jones

Force: 27955 | Joined: 1st Jan 2002 | Posts: 11683

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FXhome Team Member

FXhomer109748 wrote:

I will using FXHome Photokey2 lite for a big project at a high school in TWO days. When creating my displays from previous pictures, where I erased the original background and put it on a green background, those worked fine.
I don't quite understand the process you mention here. Why were you putting in a green background when you'd already erased the original background?

Some of the background came through.
Can you upload the original images so we can take a look? It's difficult to provide specific advice without seeing what you're working with.

Have you tried adjusting any of the Key settings?
Posted: Tue, 2nd Mar 2010, 1:32pm

Post 4 of 4

njush

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

PhotoKey 3 User Windows User MacOS User

Gold Member

So, it seems like you're posting about two issues.

1) Splotches of gray left behind in the green background.
This is caused by shadows or un-even lighting on your green screen.
If you open your photo in any tool that will report RGB pixel values in the areas that are turning out splotchy are not as bright as the areas that are keying well. PhotoKey is keying these as shadows, which is great when you want to keep ground contact shadows from your photo subject in your final comp ... but not too helpful when you want to remove the whole background.

The solution is to make sure your screen is very flat (no wrinkles or folds) and lit very evenly with lights independent of what you're using to light your subjects. Two large softbox modified strobes tend to do the trick well for backgrounds. Just don't get them too close or you'll get over-bright hot-spots, which are just as problematic for keying as shadows.

2) Spill
Just to be clear, Spill is where the screen color is evident near the edges of your subject's hair and clothes. This mostly happens when the subject is too close to the background, but can also happen naturally around the semi-transparent pixels at the edge of your subject as well as on anything reflective.
The main solution to this is to move your subject away from the background so less light reflected from the screen falls on the subject.

Hope this helps.
Have fun.