• Adobe After Effects

  Remove grey from bluescreen.

  Posted by Anandabrata Ghosh on June 20, 2007 at 10:53 pm

  Hi,

  I have created a small clip using bluescreen. I have used the effects Color Range and Hue/Saturation. I have adjusted the lightness in different ranges the last being as -100. But still there is a distinct amount of grey in the video. I am not sure what needs to be done to remove the grey from the outlines of the subject.

  Regards,
  Anand

  Kevin Camp replied 19 years, 2 months ago 2 Members · 3 Replies
• 3 Replies

• 

  Kevin Camp

  June 21, 2007 at 2:57 pm

  you are talking about a fringing or halo around footage that you keyed, right?

  it would help to know what effect or effects you used to key the bluescreen footage, but you may be able to just tighten the key with simpler choker, or possibly try remove color matting.

  some keying effects, like keylight, have built in edge color removal features that are usually set to a very neutral gray, but this can be set to another color to help blend your edges. also, keylight will allow color adjustment of just the edges. additionally, there are effects like spill supressor that may be effect the edge color, but we would need to know more about how the footage has been effected already.

  Kevin Camp
  Designer – KCPQ, KMYQ & KRCW
• 

  Anandabrata Ghosh

  June 21, 2007 at 7:42 pm

  Hi Kevin,
  Thanx again, seems like you are becoming my guiding light :). To start with I have an moving subject as an avi in the fore and a still image(tiff) in the background. I am using only two effects

  a) Color Range
  b) Hue/Saturation

  Both are used with the avi. I have tried the effects you mentioned one by one. Simple Choker works and also some of the feathered edge properties to. But still when my object is moving there are edged lines in the outline. I want to get rid of these lines from the edges completely.

  Regards,
  Anand
• 

  Kevin Camp

  June 22, 2007 at 12:58 pm

  so the avi you have was previously keyed… and the edge problem was there before you added the two color adjusments, right?

  this isn’t sounding like a common problem, and the problem may have been with the original footage or keying process. it’s a little difficult to choose the best route to go without being able to see the footage.

  i think that you might want to try and key out the edge, but gray is not a great color for keying since gray is a common value and you will be keying areas you don’t want to lose. because of that, i think you will want to duplicate your footage, hide the lower duplicate and apply minimax to the top one. set it to operation: minimum; channel: alpha and radius to a value that will remove the edge completely (don’t worry about loosing to much of the subject, this layer is to maintain the ‘core’ detail). if you need to soften the alpha at some point to blend it to the lower duplicate, try channel blur, bluring just the alpha.

  now, on the lower duplicate, apply a keying effect… color key is a simple one, just use the eyedropper to select the color that you want to key out, try adjusting the other 3 settings to see if you can remove the gray edge.

  Kevin Camp
  Designer – KCPQ, KMYQ & KRCW

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