green screen fiddlyness

[Mike Park]

If you are unrolling a futuristic transparent screen, why not use a clear piece of plastic as a stand-in. Think the thick stuff like the covers of those report folders you used in school. You would not have to key anything and the reflections off the plastic would actually enhance the look of the shot. Plus, it would give your talent something physical to use and make his hand placements steady. It would also preserve the green screen behind and make keying easier. Just a thought.

Best of luck

[Michael Szalapski]

It would be much easier to build your prop practically then enhance it with AE than it would to totally replace it. If he’s unrolling a scroll with information on it, make the scroll practically, then put the digital stuff that’s actually on the scroll there in post.
AE’s not a 3d program so sometimes placing props in a scene will never look right if they (or the camera) are supposed to be moving around.

Do not use purple for a keying color. Purple is too close to pinks which can be in human skin tones. Blue would be the color you would want to make things. Very vibrant blue.

– The Great Szalam
(The ‘Great’ stands for ‘Not So Great, in fact, Extremely Humble’)

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.

[Mike Park]

If the screen is going to be transparent, and it is going on top of anything you would see underneath, DONT use a solid material to make a practical prop, or else you will just key it out and have a hole in your footage you will have to replace with live action – a HUGE pain. Now, if it is going to be opaque, you can use any material you want since you will not see it in the finished shot anyway. I was under the impression you wanted a transparent/holographic look where it would be electronic buttons floating on a sheet of plastic or the like.

[David Bogie]

Your rental studio should have an experienced green screen gaffer or shooter. Exploit them.
As noted by others, practical effects and props are superior to fixing it in post in After Effects. AE is a compositor, not a miracle factory.

Your mention of needing to carefully key hand motion suggests you should be choosing your shooting format very carefully. You must do extensive tests with your tape/digital format and your chosen keyer long before you start spending money on props and actors.

You won’t be replacing your props by keying. You’ll be using motion tracking and that will require several more days of experimenting and research to learn how to use tracking dots and talk to the software. There are two choices now, Mocha and AE’s native tracking tools. I’ve never used Mocha myself.

Links to just about everythinn you want to know about Motion Tracking in AE:
https://help.adobe.com/en_US/AfterEffects/9.0/WS3878526689cb91655866c1103906c6dea-7c5ea.html

bogiesan

[Michael Brookes]

thank you Mike and Michael (we all have the same name, nice!)

Some really helpful points. We do want the screen to be semi-transparent for the scroll. The way I had thought of doing this was to have a solid, blue roll for the scroll part (as this needn’t be transparent and help for finger placement), and then have the actor ‘mime’ pulling the screen out with his other hand.

Alternatively, for the device the actor unfolds from his pocket, I thought of doing this in two shots – first with actual, folded-up blue paper that I can then “linear color-key” to isolate, and then another shot where he holds nothing (or the transparent material, which could work well). The device needn’t be transparent until it’s switched on.

Luckily there is no camera movement in this piece and the shots are all front on, so After Effects should hopefully be ok. This a really stylised piece so the devices are gonna be really basic outlined shapes. Still, I want it to look good(!) and for the devices to sit well within the actor’s hands.

mike

[Michael Brookes]

Hi david,

thanks for the help. We have done a test in our offices on a portable blue-screen, and it worked well. For the text though, we had the actor typing in thin air, and i later placed a tablet screen-like shape behind his fingers. So it was easier than the other devices.

I was thinking of using tracking points – we have another scene where the actor is using his watch as a PDA device. I need to look into this. However, why can’t I key the devices out? Otherwise, even with tracking, I’m going to have to paint out frame-by frame to match to finger movement. Whereas I thought as long as the devices were a solid blue I could isolate, I could then have them as a separate layer I could manipulate in AE. No?

Many thanks,

michael

[David Bogie]

[Michael Brookes] “However, why can’t I key the devices out? Otherwise, even with tracking, I’m going to have to paint out frame-by frame to match to finger movement. Whereas I thought as long as the devices were a solid blue I could isolate, I could then have them as a separate layer I could manipulate in AE. No? “

Congratulations, you’re WAY ahead of most folks who start similar threads!

I have perhaps misunderstood what exactly you are keying out. Generally, keying only works as a matte generator for flat objects like backgrounds. for instance, there’s no need to key out a screen on a PDA since it will be replaced with a tracked image. Motion in front of your blue or green screen can become a terrible mess so be sure your shooting format has the shutter speed and temporal resolution to give you the results your client expects. Faster shutter speeds can help reduce motion blur at the expense of an unnaturally sharp image. Shooting progressive can help, too, especially if your release media is destined for progressive display only.

I think you’re very far along. Best of luck, try to keep thinking ahead.

bogiesan

[Rob Hughes]

Hi Michael,

I’m just working on a similar project myself. We shot a person on green screen, interacting with a fictional coffee machine in a fictional kitchen environment. (image attached)

The environment and coffee machine were all created in 3D in maya, rendered out as still background images and imported into AE for compositing.

We didn’t actually have the actor holding things, but they were pressing fictional buttons on the fictional coffee machine.

We made all the props out of MDF and painted them green. (we took a sample of the green screen background down to a diy store and got them to paint match it).

One problem we encountered was that we drew tracking points in pencil onto the objects to represent the buttons. Now when we key, we’re having to roto out these pencil marks as the hand passes over them, simply because they’re not green!

My advice to you would be to use actual green props – so use two pieces of broom handle painted green with some green string or paper in between to simulate your scroll. (or something similar) This can all be keyed out and the hands will look like they’ve got the correct grip to insert your futuristic device.

Also as i think you’re doing, test test test – go through the whole post production process with your footage to try and discover problems…..we did some testing for our shoot, but missed this little problem, which is now causing me hassle!

Cheers,

Rob
(back to the roto!)