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Lighting For Forklift Car and Green Screen

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Hi guys,

I have a job coming up in London at Malcolm Ryan Studios shooting on HDcam with the 750. This is a green screen job where a forklift car is driving towards a pile of boxes lifting them and moving them off screen. The idea is to green screen all the boxes as they are going to be showing some footage, all boxes displaying different footage. We also want the rest of the frame very white and even. The studios are very big and will have access to all sorts of lighting equipment. The trick is not to cast any shadows in the boxes when the forklift car is approaching them and moving off screen so that the green screen will key properly.

This is going to be a locked off shot and very wide. I am going to rely heavily on spacelights and will try to avoid shadows by throwing them to the floor... There will be other shots where I will be using green screen on a woman who will later on be coming out of the pile of boxes.

How would you guys approach the lighting for this kind of job?

Also, what settings would you choose for the 750?

Thanks

Vincent De Paula
Director of Photography
+44 (0)1932 843806
+44 (0)7766 913932
www.vincentdepaula.com


Vincent De Paula wrote:

>> How would you guys approach the lighting for this kind of job?

It sounds like you're going for a really flat/even look which helps - I'd light it for the look 1st as some slight shadowing on the screens isn't going to kill the comp. Sometimes the kind of lighting to overcompensate for the screens risks looking more fake than the worst comps. the even light situation you've described is the right direction.

Large frames of soft light from the front to wrap in the spacelights from above... things you have no doubt prepped already, often overlooked: VFX should have their fave saturated green colour - that will help since you're not able to boost the green saturation with the lighting.

Beyond that, I'd look into ELP's or some other way of making the green panels on the boxes backlit from inside via batteries (do I have this right ? the screens are on the boxes, yes?). Or LED arrays backlighting a green chroma slide you can have made? Something like that, but if 3-6 sides of a cube are to be shown, or there's no border to the screens, then forget it! Then there's add'l issues like a green cast onto the floor/forklift.

Remember also that the green screens on the boxes are more necessary to comp an image onto a box if a FG element overlaps (different issue for the girl in green). Tracking on its own is more dependent on the boxes themselves, and less on a perfectly lit green screen alone. I've run into misunderstanding here from helpful AD's & Art Directors and such asking to put a screen onto something with no overlap on it and plenty of things to track from (such as a TV burn-in). Usually there's nod from the VFX Super and they'll tell us what they need.

Mark Doering-Powell
LA based DP


I would be more concerned with having good tracking marks on the boxes rather than having them being a perfectly keyable colour. Ultimately what you are going to do is just place an image onto them. The shadow might be a nice thing to keep - as long as it is not too heavy (to destroy your key) they will be able to key it back over the image (to whatever degree they like) to really set a believable composite.

This is partly an aesthetic call but... What I would do is shoot boxes made of black plexi (or green if you can't sell them the black). Then place small circular red (or any other colour) tracking marks, so they don't interfere with moving specular highlights. This way you will have specular reflections to key back and sell the composite. And the tracking points to corner pin the images.

You need to ask yourself, what am I getting from the green?

Tom Peters
VFX/DP
NYC


>> You need to ask yourself, what am I getting from the green?

Sorry, I've long since lost the original question in this thread, but do you have any foreground action passing in front of the boxes? If so, the green might make it easier to pull the fg off the bkg before you comp the images onto the boxes...

If you don't have foreground elements passing in front of the boxes, then all you need is to be able to find the corners of the boxes...Bear in mind that if you have stacks of boxes or edges or corners of boxes occluding other boxes or stacks of boxes, then you DO have foreground elements passing in front of boxes.

I would suggest speaking with whomever is going to have to composite these elements together to find out whether a reflection pass will help them or not... it is an open question what they would be reflecting, other than other boxes with images on them (which would have to be matted in anyway)
If you do have foreground elements going past the boxes, reflection pass might be useful but it really depends on the specifics...the main thing (if the boxes are going to be replaced full edge to edge, corner to corner) is to make sure you can see where the corners of each plane are. You might consider using different colour trackers on adjacent facets of the boxes if it is possible to see two facets at once of the same box, otherwise, if one of the corner marks gets occluded, it might not be obvious which face you are looking at.

Having forgotten the parameters as outlined in the original post, I apologize in advance if I have galloped off down the wrong path here. From a political standpoint, involving the post house in the discussion up front. may protect you from getting slagged off by them as they are posting the spot...

Mark Weingartner
LA based VFX
(I'm not a compositor...but my choices on set regularly torture them)


Mark Weingartner wrote:

>>Sorry, I've long since lost the original question in this thread, but do you have any foreground >>action passing in front of the boxes? If so, the green might make it easier to pull the fg off the bkg >>before you comp the images onto the boxes...

We have a forklift car driving toward the boxes, picking them up and driving them off the screen. I haven't been able to check the shape of material of the boxes yet, and tomorrow we will be running a lighting test and hopefully we'll come up with some ideas. The fact that the boxes are being picked up in this manner is also alarming me as that would create a lot of "shaky" movement from the boxes that might interfere with the keying.

Vincent De Paula
Director of Photography


>>The fact that the boxes are being picked up in this manner is also alarming me as that would >>create a lot of "shaky" movement from the boxes that might interfere with the keying.

Reduce your shutter to at least 1/60th, or a little more if you have the stop. That'll help with the shakiness. Motion blur can be reintroduced later if needed. Sometimes you can do tracking marks with another colour that doesn't appear in the environment (we've used pink post-it notes before) and they can be keyed out later.

If you find a lot of shadows falling on the boxes you could try replacing the side of the box with milk plastic and lighting it green from the inside. There might be a little more danger of cast light from the boxes but shadows wouldn't be an issue. Not sure how you'd want to do that... green power cables?

Is there an SFX supervisor on the job? These are all questions for them to answer, as they'll be the ones making it work. (Green screen in interlaced HDCAM... phew!)

Art Adams
Director of Photography
Film | Hidef | Video

San Jose, CA, USA
www.artadams.net
415.760.5167


Well ... finally I had about 18 spacelights hanging from the very high ceilings of Malcolm Ryan Studios in Wimbledon, and they provided enough ambience light and didn't cast any shadows in the boxes at all.

Regards

Vincent De Paula