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How can I make a sky replacement, not look green screened?

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ryan elder
How can I make a sky replacement, not look green screened?
on Jun 4, 2018 at 1:17:46 am

Basically I want to do the day for night effect, and I watched different tutorials on how to do it. The tutorials say to use a sky replacement and darken the sky replacement so it looks like night. I tried that but when do I do, it looks green screened, unlike the tutorials I watched.

Also every object has a bright outline around it, after doing the sky replacement. If you look in the video example I posted, the tree has a bright outline, and the powerlines have a bright outline, etc. But in the tutorials I watched, there are no bright outlines in the objects that are in front of the sky replacement.

Can anyone tell me what I am doing? Thanks for any help, I really appreciate it ☺







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Kalleheikki Kannisto
Re: How can I make a sky replacement, not look green screened?
on Jun 4, 2018 at 6:51:51 pm

Do you have a still image from the original footage?

In general night lighting is blue, and the objects on the ground are darker than the sky. There are orange street lights in existence, but this scene doesn't look like it is lit by streetlights.

Kalleheikki Kannisto
Senior Graphic Designer


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ryan elder
Re: How can I make a sky replacement, not look green screened?
on Jun 4, 2018 at 10:08:27 pm

Yep here, is the original ungraded footage, straight out of the camera:







This is just a test shot, but I do want the orange streetlight night look, and do not want the blue night look.

So I want to do day for night, cause it helps with lighting, compared to night, plus the cast and crew would normally rather work during the day, than at night.

So what can I do to get the day for night look, without it looking green screened like that? I have tried several different sky replacements, but it still looks fake, compared to tutorials on how to do it.


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Steve Bentley
Re: How can I make a sky replacement, not look green screened?
on Jun 5, 2018 at 6:48:01 am

It doesn't look like there's a lot of blue sky there to key (but I didn't bother to see how much was in the Raw file to pull out - since the upload was compressed). So you might be better to do a roto of your "skyline" since its a locked off shot. Then put the sky in you want and crush the levels of everything else down. The tree is an issue, so you will have to crush the levels to pull a matte and combine that with your roto. Keep in mind as K mentioned above, those objects tend to be darker than the sky so forget the matte and you could crush the levels just a little and then multiply/blend the tree etc right over the sky with no matte at all.

Notice that parking sign. Unless you have a car head light on a sign at night, its usually in silhouette against the glow of the sky - and all skys glow unless you are waaaaaay outside of town. So you might not need a pulled matte at all.

Cinema tends to use a blue cast to trick you into thinking its night (the opening scenes of Jaws are day for night and blue blue blue). So you can use sodium vapour pools color blended into the shot over a general blue cast and this gives a classic warm/blue coloring we expect in night shoots.
If you really want to get tricky, they tend to water the streets down for night shots to get interesting reflections. Again this is something we have come to expect in film so the more of those kinds of things you can add the more you fool the viewer into accepting the old tropes.

The white objects are an issue as they are going to get muddy as you try and darken them enough. Make a roto and use the roto as a multiplied element for a silhouette of those objects. There is very little detail in night time, er, details.

Shadows at night are actually more contrasty than the ones in the daytime (the blue daytime sky adds some fill to lighten them up) So don't be afraid of contrast as you darken down.

You can also add some noise over all. CCD's of todays camera get pretty noisy in the dark and high ISO films used for night shooting are the same (Amadeus used only practical lighting on film - the opening scenes are very grainy) and we've come to expect it (just like the totally unrealistic blue cast from the moon). The noise will also help tie the fake sky into the real footage.
Adding some offscreen flares (calling Mr. Abrams, Mr. JJ Abrams...) can create a fog that will also tie different elements together. It also helps even out the black levels which can really scream "fake" in Day for Night.



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ryan elder
Re: How can I make a sky replacement, not look green screened?
on Jun 5, 2018 at 11:46:10 am

Okay thanks. I don't want to use blue though cause the shoots we are going to do, are in the city and there are plenty of streetlights around, so I think it would make more sense to make the audience believe that the street lights are on, which means orange would be better. So is it possible to go for an orange look rather than blue?

As for adding noise, the point of day for night, is to footage without noise since night footage can have a lot more noise. So I feel if I add noise, I would be negating the point of day for night, wouldn't I?


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Kalleheikki Kannisto
Re: How can I make a sky replacement, not look green screened?
on Jun 5, 2018 at 2:30:57 pm
Last Edited By Kalleheikki Kannisto on Jun 5, 2018 at 2:36:41 pm

My point is, you can start with a blue tint background to give it the night look, then add any color lighting, like the orange street lights. To make it at all believable, you will have to adjust the lighting as if it was coming from those point light sources. Here's a quick photoshop mockup from a still image from your footage. Something along these lines, perhaps.

Note that there was no need for sky replacement, I curved the colors to a deep blue, which took care of the sky. There's an added gradient from darker to lighter in the sky.

You would likely want to have the car stand out more, it being the object of interest.



Kalleheikki Kannisto
Senior Graphic Designer


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Richard Garabedain
Re: How can I make a sky replacement, not look green screened?
on Jun 5, 2018 at 7:06:57 pm

your making it a night shot? no wonder your having problems


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Richard Garabedain
Re: How can I make a sky replacement, not look green screened?
on Jun 5, 2018 at 7:07:28 pm

although Khangistan has got a pretty good look there


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ryan elder
Re: How can I make a sky replacement, not look green screened?
on Jun 5, 2018 at 10:17:38 pm

Okay thanks Kalleheikki, I really dig how you made the picture look! However, by not doing a sky replacement, when you bring it down that dark, the actor's face cannot be seen, and if I do close ups shots at night, the faces will be really dark. So wouldn't I need to do a sky replacement for close up shots to not be too dark?


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ryan elder
Re: How can I make a sky replacement, not look green screened?
on Jun 5, 2018 at 10:33:59 pm

There is another thing... You did masking in order to make it look like this. If I do day for night, do I have to do masking? Cause whenever I try it in AE, the program fails to track the mask while the camera moves, so I have to therefore, do it all manually, and this will be a lot of of frames and a lot of work, which makes me think maybe I should just get a Sony A7s, which is really good for night shooting, without noise.

So do I have do use masks for each frame, as the camera moves?


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Tero Ahlfors
Re: How can I make a sky replacement, not look green screened?
on Jun 6, 2018 at 4:14:54 am

[ryan elder] "and this will be a lot of of frames and a lot of work"

Here's the thing. Not every VFX shot work can be automated and automagically plugined to where it needs to be and you'll need to work on it manually. Especially if it is an extreme effect on a piece of footage that wasn't shot to help in the way to help the VFX artists. I've done a few day to night shots but the crew knew how to shoot it and it was pretty straightforward.


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ryan elder
Re: How can I make a sky replacement, not look green screened?
on Jun 6, 2018 at 4:20:13 am

Okay thanks, how would be the best way to shoot it then for AE to do the best job?


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Dave LaRonde
Re: How can I make a sky replacement, not look green screened?
on Jun 8, 2018 at 1:25:14 pm

[ryan elder] "Okay thanks, how would be the best way to shoot it then for AE to do the best job?"

You might want to think about shooting dusk for night rather than day for night. A lot less problems with daytime shadows that way.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Kalleheikki Kannisto
Re: How can I make a sky replacement, not look green screened?
on Jun 6, 2018 at 8:22:05 pm
Last Edited By Kalleheikki Kannisto on Jun 6, 2018 at 8:25:38 pm

[ryan elder] "So do I have do use masks for each frame, as the camera moves?"

As for tracking, you should be able to point track or planar track (with Mocha) and attach null or layers that function as light sources, local lighting, etc. It's not going to be fast nor easy. The car would have to be tracked separately if you want to make it stand out with a different color adjustment. Same with (people and) faces.

Actually shooting at night is going to be about 100 times faster than taking that mid-day footage and turning it into night. Especially if you have a lot of night footage with moving camera.

Kalleheikki Kannisto
Senior Graphic Designer


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ryan elder
Re: How can I make a sky replacement, not look green screened?
on Jun 6, 2018 at 9:31:03 pm

Okay thanks. It's just that shooting at night is much more expensive cause you need much brighter lights, and that's the problem for me.

Plus I can shoot whatever I want at night and no one cares, as long as I don't light the streets. But lighting the streets requires costly permits as well.


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