I am going to run my stop motion partially with the use of chroma keying. The scene is on the surface of a planet. The background I would be using will be the space sky with stars..     I am just confused if I should use green background or blue background? And how can I stand the cardboard paper? Thanks!

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Use the colour which is the most unlike the colours in your foreground.  Especially the puppets.  If you had characters wearing blue jeans you would definitely not use blue screen, which is why I am using green at the moment.  If there are green plants on your planet, they would key out as well, so you would use blue.  

Or, if there is no blue or green, use the colour which won't be as noticeable against the background.  If you end up with a few greenish or bluish pixels around the edge, blue would not look as bad if you put a blue sky in where the blue screen was.   But if it was green grass and trees, a little green would be less noticeable.  With a starfield it's hard to say.  Maybe I'd pick blue.  What software are you keying with?  

My greenscreen is fixed onto the wall, with a 2 ft gap between the back of the set and the green screen, so my puppets don't cast shadows onto the screen.  Shadows mean there are more shades of green to key out, so more risk of bits of your puppet going transparent if they look even a little bit greenish in spots.  Also, the lights that light the screen are different to the ones that light the puppets.  Because there is a gap, the green screen is further back and needs to be bigger than if it is close, so maybe you don't have that option.  It is actually a big piece of green fabric made especially for chroma keying, but I have also used cardboard painted green or blue.

I have a frame covered with 3mm ply against the wall, so I can just staple green cloth or card onto it, then take it down when I want something else like a painted scenic backdrop.  Another option would be a big sheet of ply or particle board just leaning against the wall.  Or if there is a picture rail, hanging a rod from picture hooks with the cloth hanging from that.  Or if there is a window with curtains, maybe close the curtains and pin the card to the curtains.  Or maybe blue-tack to stick the card on the wall.  Or tape, if you (and parents/landlord) don't mind wrecking the paint on the wall when you peel it off.

 

I painted a board green (thanks to Peter Montgomery for the advice).

What keying software do you recommend? I might probably use blue.

StopmoNick said:

Use the colour which is the most unlike the colours in your foreground.  Especially the puppets.  If you had characters wearing blue jeans you would definitely not use blue screen, which is why I am using green at the moment.  If there are green plants on your planet, they would key out as well, so you would use blue.  

Or, if there is no blue or green, use the colour which won't be as noticeable against the background.  If you end up with a few greenish or bluish pixels around the edge, blue would not look as bad if you put a blue sky in where the blue screen was.   But if it was green grass and trees, a little green would be less noticeable.  With a starfield it's hard to say.  Maybe I'd pick blue.  What software are you keying with?  

My greenscreen is fixed onto the wall, with a 2 ft gap between the back of the set and the green screen, so my puppets don't cast shadows onto the screen.  Shadows mean there are more shades of green to key out, so more risk of bits of your puppet going transparent if they look even a little bit greenish in spots.  Also, the lights that light the screen are different to the ones that light the puppets.  Because there is a gap, the green screen is further back and needs to be bigger than if it is close, so maybe you don't have that option.  It is actually a big piece of green fabric made especially for chroma keying, but I have also used cardboard painted green or blue.

I have a frame covered with 3mm ply against the wall, so I can just staple green cloth or card onto it, then take it down when I want something else like a painted scenic backdrop.  Another option would be a big sheet of ply or particle board just leaning against the wall.  Or if there is a picture rail, hanging a rod from picture hooks with the cloth hanging from that.  Or if there is a window with curtains, maybe close the curtains and pin the card to the curtains.  Or maybe blue-tack to stick the card on the wall.  Or tape, if you (and parents/landlord) don't mind wrecking the paint on the wall when you peel it off.

 

What specific kind of software for keying do you reccommend? Thanks!

Sorry didn't see this before.

After Effects.  

Much as I dislike it, it does a good job of keying, and my favourite post production  tool (TV Paint Animation) does a poorer job because it has no edge control.  I am using the Color Key in AE.  I click on the green screen to select the colour to key out.   (You can select any color, it works just as well with blue.)   That only makes a few dots disappear, so next  I increase the tolerance to get more shades of green, usually to around 30.  Much more than 32 and I was getting parts of my puppet start to go transparent as well, much less than 28 wasn't getting all the screen.  Then I expand the edges by 2 pixels, which eats into the edges of the puppet a little,  and feather the edges by 2.5 pixels.  That gets rid of the fringe of green pixels around the edge of the puppet, which are not quite green enough to key out, but still look way too green. Then feathering it softens the edge.  (It's called feathering in Photoshop, something else in AE but I can't remember what, but does same thing.  Don't know why Adobe can't use the same terminology for both of their programs. Anyway fiddle with the controls.)  I was working in 3888 x 2560 pixels, if I had already resized to HD I might have used fewer pixels to get rid of the fringe.

There is also something called Keylight in AE, which looked very promising.  I tried it, selected my green, and it looked like it was all done instantly, all shades of green gone, soft edges, all with one click.  Amazing!  But when I rendered it out I found moving noise all over my puppet.  Big soft blobs, rather than tiny pixel-sized noise.  The image didn't seem quite as sharp either.  I googled and found a video on Youtube from another guy who had the same problem with noise and he couldn't figure it out.  I went back to doing it in Color Key, a step at a time.  If I didn't get the noise, Keylight was much quicker and better, but I got there in the end.

 In one shot I had to run 2 passes, select one area of lighter green and key it out, then select another, darker area and key it out.  If I expanded the tolerance to enough shades of green to do both at once, it ate into my puppet.  But in 2 parts, it worked.  The levels you need to set would depend on how even your blue screen is lit, and how much you avoid any blue spill light reflecting onto your puppet.  Mine wasn't perfect, but it was good enough.

  

That was quite long but very helpful! Thanks!


That was quite long but very helpful! Thanks!
StopmoNick said:

Sorry didn't see this before.

After Effects.  

Much as I dislike it, it does a good job of keying, and my favourite post production  tool (TV Paint Animation) does a poorer job because it has no edge control.  I am using the Color Key in AE.  I click on the green screen to select the colour to key out.   (You can select any color, it works just as well with blue.)   That only makes a few dots disappear, so next  I increase the tolerance to get more shades of green, usually to around 30.  Much more than 32 and I was getting parts of my puppet start to go transparent as well, much less than 28 wasn't getting all the screen.  Then I expand the edges by 2 pixels, which eats into the edges of the puppet a little,  and feather the edges by 2.5 pixels.  That gets rid of the fringe of green pixels around the edge of the puppet, which are not quite green enough to key out, but still look way too green. Then feathering it softens the edge.  (It's called feathering in Photoshop, something else in AE but I can't remember what, but does same thing.  Don't know why Adobe can't use the same terminology for both of their programs. Anyway fiddle with the controls.)  I was working in 3888 x 2560 pixels, if I had already resized to HD I might have used fewer pixels to get rid of the fringe.

There is also something called Keylight in AE, which looked very promising.  I tried it, selected my green, and it looked like it was all done instantly, all shades of green gone, soft edges, all with one click.  Amazing!  But when I rendered it out I found moving noise all over my puppet.  Big soft blobs, rather than tiny pixel-sized noise.  The image didn't seem quite as sharp either.  I googled and found a video on Youtube from another guy who had the same problem with noise and he couldn't figure it out.  I went back to doing it in Color Key, a step at a time.  If I didn't get the noise, Keylight was much quicker and better, but I got there in the end.

 In one shot I had to run 2 passes, select one area of lighter green and key it out, then select another, darker area and key it out.  If I expanded the tolerance to enough shades of green to do both at once, it ate into my puppet.  But in 2 parts, it worked.  The levels you need to set would depend on how even your blue screen is lit, and how much you avoid any blue spill light reflecting onto your puppet.  Mine wasn't perfect, but it was good enough.

  

The Keylight plugin is far superior to Colour Key. It might not work instantly (Nick mentioned some noise), but only because it has options that need tweaking. Don't give up! Not all footage is the same, so it needs more info than just which colour to key. It's a powerful keyer that's worth taking the time to learn...

Here's a tutorial that explains how to use it: http://www.videocopilot.net/tutorial/basic_color_keying/



StopmoNick said:

Sorry didn't see this before.

After Effects.  

Much as I dislike it, it does a good job of keying, and my favourite post production  tool (TV Paint Animation) does a poorer job because it has no edge control.  I am using the Color Key in AE.  I click on the green screen to select the colour to key out.   (You can select any color, it works just as well with blue.)   That only makes a few dots disappear, so next  I increase the tolerance to get more shades of green, usually to around 30.  Much more than 32 and I was getting parts of my puppet start to go transparent as well, much less than 28 wasn't getting all the screen.  Then I expand the edges by 2 pixels, which eats into the edges of the puppet a little,  and feather the edges by 2.5 pixels.  That gets rid of the fringe of green pixels around the edge of the puppet, which are not quite green enough to key out, but still look way too green. Then feathering it softens the edge.  (It's called feathering in Photoshop, something else in AE but I can't remember what, but does same thing.  Don't know why Adobe can't use the same terminology for both of their programs. Anyway fiddle with the controls.)  I was working in 3888 x 2560 pixels, if I had already resized to HD I might have used fewer pixels to get rid of the fringe.

There is also something called Keylight in AE, which looked very promising.  I tried it, selected my green, and it looked like it was all done instantly, all shades of green gone, soft edges, all with one click.  Amazing!  But when I rendered it out I found moving noise all over my puppet.  Big soft blobs, rather than tiny pixel-sized noise.  The image didn't seem quite as sharp either.  I googled and found a video on Youtube from another guy who had the same problem with noise and he couldn't figure it out.  I went back to doing it in Color Key, a step at a time.  If I didn't get the noise, Keylight was much quicker and better, but I got there in the end.

 In one shot I had to run 2 passes, select one area of lighter green and key it out, then select another, darker area and key it out.  If I expanded the tolerance to enough shades of green to do both at once, it ate into my puppet.  But in 2 parts, it worked.  The levels you need to set would depend on how even your blue screen is lit, and how much you avoid any blue spill light reflecting onto your puppet.  Mine wasn't perfect, but it was good enough.

  

Thanks Evan, I will check out the tutorial!   Keylight did look like a better way to do it.  But it was far from clear what the various tools and options were for, I was never going to figure it out without help.   Basically I remain a beginner with AE, because it pisses me off so much each time I use it, I avoid it for the next 6 months and forget what little I did learn.  I can do almost everything else in TV Paint in fewer steps and less stress, but not decent colour keying. 

For anyone interested in a FREE tool for chromakeying and one that will do a good job of it, you might want to check out Blender. It will take a bit of a learning curve to learn how to use it. There are some excellent tutorials on YouTube. The normal reaction to Blender is to think it is for 3D, but Blender has a compositor and a video editor.  For chromakeying, color correction, and etc, you use what is called the 'Node Editor'.

I have heard of that software many times but I never tried it. I will take a try on downolading blender. Thanks!

Keith Ray said:

For anyone interested in a FREE tool for chromakeying and one that will do a good job of it, you might want to check out Blender. It will take a bit of a learning curve to learn how to use it. There are some excellent tutorials on YouTube. The normal reaction to Blender is to think it is for 3D, but Blender has a compositor and a video editor.  For chromakeying, color correction, and etc, you use what is called the 'Node Editor'.

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