How can I fake algae/mould growing on cars/windows/signs??

[thomaslove]

Hey folks.

I'm working on a short post-apoc film and I'm trying to figure out the best way to fake that green alge/mould that grows on smooth surfaces that have been left exposed to the elements. I'm looking for a way to achieve this in-camera but am open to any vfx ideas as well.

Here's some real life photos of the effect I'm looking for;




From looking at some behind the scenes photos of The Girl With All the Gifts (2016), it seems there is some kind of spray or paint that can be used.




(more behind the photos here for those interested)

Does anyone know what this mixture might be? Can it be made from household materials or will I have to buy from some specialist shop?

Thanks for any ideas/help!

[indietalk]

There's a brand of movie spray paint that washes off.

Some colors that may work: Dirt, Brown Rust, Nicotine, Dark Patina, Fuller's Earth, Dulling. Some darker colors below, some misted on, dulling, and dirt. Window screens or similar for some patterns. Layers.

http://www.hollywoodexpendables.com/...y-aging-11-oz/

You could combo in some cgi for the right look, color grade, etc.

[indietalk]

They also make a dust you can wet and put on to look like mud.

I think Nicotine is your greenest color. But nothing is green green. But you can definitely get the look of the car 3rd row down in your pics.

https://shopbleedingartindustries.co...aging-mud-dust

[thomaslove]

Originally Posted by indietalk

There's a brand of movie spray paint that washes off.

Some colors that may work: Dirt, Brown Rust, Nicotine, Dark Patina, Fuller's Earth, Dulling. Some darker colors below, some misted on, dulling, and dirt. Window screens or similar for some patterns. Layers.

http://www.hollywoodexpendables.com/...y-aging-11-oz/

You could combo in some cgi for the right look, color grade, etc.

Originally Posted by indietalk

They also make a dust you can wet and put on to look like mud.

I think Nicotine is your greenest color. But nothing is green green. But you can definitely get the look of the car 3rd row down in your pics.

https://shopbleedingartindustries.co...aging-mud-dust

This could be big help - especially for the rusty effect. Thanks. I'll look into this.

[mussonman]

You could composite it in After Effects, for a cheaper alternative

[indietalk]

Depends how many cars. A parking lot? AE. A car or two? Practical, AE, or combo. I could see the Dulling spray coming in real handy just to cut the shine of glass and metal, if the cars are newer. Patina too.

[Kaiborg]

I'd wrangle the catch-bag from a freshly used lawn-mower, mix up all that cut grass with cornstarch and water, and paint it on. It's just an idea, and I'd definitely test it first... that kind of thing either works, or doesn't.

[sfoster]

I wonder if the instructions for making a gilly suit can be adapted for a vehicle

[UneducatedFan]

I've never tried it but I've heard oatmeal (big 5 gallon bucket kind) with food coloring or sawdust soaked for a while in colored water or water colors or something.

Again, I don't know if it really works or not.

[indietalk]

That's for chunky blood.

[UneducatedFan]

Originally Posted by indietalk

That's for chunky blood.

Doh!

[thomaslove]

Originally Posted by mussonman

You could composite it in After Effects, for a cheaper alternative

Originally Posted by indietalk

Depends how many cars. A parking lot? AE. A car or two? Practical, AE, or combo. I could see the Dulling spray coming in real handy just to cut the shine of glass and metal, if the cars are newer. Patina too.

Great shout. I'm gonna have a play on AE tonight, see what I can come up with.

Originally Posted by Kaiborg

I'd wrangle the catch-bag from a freshly used lawn-mower, mix up all that cut grass with cornstarch and water, and paint it on. It's just an idea, and I'd definitely test it first... that kind of thing either works, or doesn't.

Originally Posted by UneducatedFan

I've never tried it but I've heard oatmeal (big 5 gallon bucket kind) with food coloring or sawdust soaked for a while in colored water or water colors or something.

These both sound like fun! I will do some experiments with these ideas and see how I get on!

Originally Posted by sfoster

I wonder if the instructions for making a gilly suit can be adapted for a vehicle

Interesting! Where can I find these instructions?