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Chroma Key for Lego

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Chroma Key for Lego

Postby Peppermint Pig » Tue Sep 11, 2007 6:24 am

The following images were masked (cut out) by hand using a brush in mask mode to trace the outlines (graphic work I did for my brother, SG). While the results are attractive, it's very time consuming!!! Eating into the time I could be using to build (I hardly post anything!):

http://www.brickshelf.com/gallery/Stone ... ost_01.jpg
http://www.brickshelf.com/gallery/Stone ... tor_11.jpg

So...

I've been pondering the issue of 'green screening' for Lego photography and video. Clearly, green and blue screens are not suitable for Lego chroma key work since they are such common colors in the Lego universe. Any ideas on what the best 'universal' chroma key color for Lego would be? I'm guessing lavender/orchid, if it contrasts enough from blue-violet, stays cleaner and more saturant than sand purple, stays brighter than purple, and avoids warm pink tones. Has anybody done any editing work along these lines?
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Re: Chroma Key for Lego

Postby E of Alshire » Tue Sep 11, 2007 12:16 pm

Peppermint Pig wrote:Has anybody done any editing work along these lines?

No. I tend to just build.

Nice job, though.
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Postby Dunechaser » Tue Sep 11, 2007 7:16 pm

Doing that sort of thing certainly does improve the presentation (which I'm all for), but I've never had the time/talent/inclination to do so myself. I just take pictures on a neutral background. Of course, you can't necessarily do that for monstrous creations, but it works for the scale I build at.
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Postby Fry_slayer » Wed Sep 12, 2007 2:13 am

Heres a chart of colors which IMO might work.

Image
Green would work if it is this sort of luminous green, just dont try doing it with a forest shot :lol:

The key is to get the ones which are as luminous as possible and to have sufficient lighting so there is enough contrast to separate the bricks from the background. However the choice of background color would no doubt affect the picture outcome and would require some hue adjustment later.

At any rate I doubt u can reach the point which after you got the shot you could settle the chores with one click on magic wand tool. The shadow produced on lighting will inevitably mess things up a bit.

Anyway good luck and do let us know, not all of us has the resource to experiment with these :wink:
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Postby Peppermint Pig » Wed Sep 12, 2007 4:52 am

Of course, you can't necessarily do that for monstrous creations, but it works for the scale I build at.


Well, I don't think it's impossible, but it does require some forethought. A large sheet of green muslin (a cloth with low sheen), can be had for a bit of cash on E-Bay or at a fabric store. I'm afraid, though, that green muslin can be a problem with Lego in Lime and Bright Green as I mentioned.

Green would work if it is this sort of luminous green, just dont try doing it with a forest shot


LOL. Yeah. Not only is Lego difficult from a color perspective, there's also the reflection of light on the plastic (which can be corrected to a point), and a brightly lit green screen could reflect its glow, bleeding on your scene/models if positioned nearby. We don't want that!

My initial point was to find a color that would pose the fewest issues: A 'universal' chroma color for Lego. Magenta, Orange, and Turquoise are colors I like using, and as Lego colors, that would disqualify them. :P

The key is to get the ones which are as luminous as possible and to have sufficient lighting so there is enough contrast to separate the bricks from the background. However the choice of background color would no doubt affect the picture outcome and would require some hue adjustment later.


I agree. The chroma color should have a cleanly character: Bright and saturant on its own, not requiring a great deal of lighting, creating the fewest issues in all regards.

At any rate I doubt (you) can reach the point which after you got the shot you could settle the chores with one click on magic wand tool. The shadow produced on lighting will inevitably mess things up a bit.


I think I can solve this issue. There's much talk about soft box screens and 3 point lighting (google it!). That would help with the model, but there would still be the issue of the screen color itself. Experts I've read about suggest that the screen needs to be evenly lit, which may or may not require an additional lighting setup, and this may be beyond the means or interest of most people photographing their Lego.

If you just have small models, a sheet of draped paper and two lights is sufficient.

Here's what I'm thinking might work. The best color is probably the one in the bottom right corner.
Image


Anyway good luck and do let us know, not all of us has the resource to experiment with these


Thanks for your support. I will bring knowledge to the masses, and hopefully provide some economical solutions to all of these problems so that the art of Lego photography is advanced (maybe, lol). :)
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Postby lil Jon » Thu Sep 13, 2007 7:21 am

That looks amazing. You've done some outstanding work.

I think I can bring a little advice to the subject matter. At my university, I had some experience with a green screen. As you probably know, sometimes the color reflects onto the subject you're photographing/video recording, and you end up "chroma keying" out some of said subject thus it looks transparent near the edge?

Well, if you have enough lights and gel filters, you can back light the subject with magenta to cancel out the green. That is, if you're using a green screen. You'd have to use the opposite light of whatever color you decided to use.

Anywho, your work is every impressive. Hope you understood anything I said.
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Postby Peppermint Pig » Thu Sep 13, 2007 9:56 am

Yes, I understand clearly. That's a good tip! I have some colored lights and a spare light fixture I could use. My only issue is that most of my photography takes place in a tight space, with the table against the wall... I could maybe also use a large sheet of paper in a contrasting color, and place those off camera to the left and right as light reflectors so the shiny Lego soaks it in.
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