Monday, 11 November 2013

Mother's Days : Chromakey : Test 01

Chromakey ;
(Communication Arts / Broadcasting) (in colour television) a special effect in which a coloured background can be eliminated and a different background substituted Also called colour separation overlay

As there will be a lot of green screen use in this animation, I'll need to do a variety of tests to get the best results. Here is test one. I found it really interesting, and not overly hard using this method.

Figure 01. Close view of the green screen setup

Figure 02. Lights in the setup

Figure 03. The Green Screen Setup

While I was taking pictures, I moved the object around on the area and found it to be true that the objects are better further away from the green screen as there were less shadow issues.

Clip one shows the visuals through each stage of my process, clip two shows the same thing but with added text at each phase.

Clip 01.

Clip 02.

I like the results for a first attempt at using a green screen.

The next thing to work out is how to apply some kind of shadowing, and to test this method on footage rather than a still image.

Figure 04. Original Photo

Figure 05. Chromakey Test 01


  1. Ok step and animated object.

  2. Great stuff, Nat - was pretty certain you'd ensure you'd get this tech working for you. Really nice breakdowns too - looking forward to seeing some animation + green screen on here too. Onwards and upwards, and all that :)

  3. Hi Nat - see link:

  4. Hey Ms. Urwin!!

    Please see this post:

    Hopefully I'll see you next week for Part 2 of the Interviews :)
    Thanks again!


  5. just been checking around the CGAA PWTM blog and landed on your page here. Cool stuff you have going on here. Its good to see someone whos actively experimenting with the shoot aspects in the 3d production world.
    id like to give some insight about green screen from an industry point of view...
    normally a widely popular choice for shooting as its striking color is usually vastly different from that of the shoot subject it makes creating keys a fairly straight forward job. However, as with most things in the VFX world this is not always the case.

    A perfect example of this would be if you needed to shoot an object that contains reflective surfaces. Having a bright colored environment would mean that it would be visible in the specular/reflection of the object, and when it comes to comping, at that green mushy tint will make the object stick out. I guess here a possible solution would be to grade the green out of the highlights. Often less than ideal. a better solution would have been to shoot the object with a "grey-screen" background. Slightly harder to get a key from, but will save more of the natural reflections from shooting (which is sometimes needed rather than being replaced in 3d, which again is always another option...)

    As im sure you know for "green screen" any color can be used as long as its contrastingly different from the subject it will always work. Consider the shoot subjects materials first to optimise the way in which you shoot it. I know the above is just a test, but, its also good to consider lighting too, i can see that your shoot object has been lit with a light from the (camera) left, looking at the back plate you have comped it on to , its quite overcast, and more of a scattered diffuse lit backplate. Having an item that has a non similar lighting setup will make the composited item stick out, (again i know it was only a test) as there is no obvious direct light source in the backplate, i would have lit the object from the top, and have the light further away (to help scatter the light more). However, if your desires were to "relight" the backplate to have the stron light from the left, then this would have to be done in 3d.

    Also for the grey screen method, shadows can be extracted much easier too, its also nice to retain a some of the natural ambient shadowing from objects, Helps with the realism and bedding of the item into the scene

    great that you are experimenting with shoot techniques!

    sorry for the essay,t i am in between renders/project feedback meetings and thought id share some rambling thoughts....

    Glassworks London

    1. Hey Fletch,

      Yes that is quite an essay here, but a much appreciated one! Your feedback and advice is always welcome here. I'll take that onboard and see how the next test turns out.

      Thanks again!