Basic Blue Screen and Green Screen Photography DVD

Basic Blue Screen and Green Screen Photography DVD by VCE.com

Introduction: The technology of compositing blue screen and green screen has improved to the point where you can pull a chroma key matte off of almost anything. However, the better the original photography and set-up, the better the matte extraction and composite.

Concept of Blue / Green Screen Blue Screen was originally invented as a film technique to separate the actors and composite them over another background. But why blue? Blue may have been chosen because it is least prominent in skin tone. Skin tone is made of a combination of red and green with a little blue.

What should I shoot: Blue Screen or Green Screen? The choice can be subjective as well as technical. If you are shooting on film and plan on doing the composite through traditional optical methods, you must shoot blue screen.

Subjective Considerations. Is there one overall, overriding theme that would exclude one or the other? i.e. A sequence of Army personnel wearing green fatigues and green camouflage paint would have an overall green bias and might be better shot blue screen for better separation.

Is there a certain lighting scheme for the foreground which is better complemented with one type of screen or the other? A warmly lit scene might separate better with a blue screen. A cold or daylight lit scene might separate better with a green screen.

Technical Considerations On film, the green layer has the finest grain structure. On NTSC video, the green channel has the highest sampling rate.

The blue layer of film is sharpest but is also the grainiest layer. In video, it is the noisiest channel. If you are shooting DV Video (4:1:1), it is probably best to stick with green screen.

Sources of blue/green screen:

Materials: Best materials for blue or green screen for rent are the Digital Green or Digital Blue spandex material available from Composite Components. This provides the best reflectance of the desired color. The "economy" method is the old "Chroma" Green and "Chroma" Blue or Tempo screen which is a spongy material available for rental. This material is not preferred.

KinoFlo Lighting packages are available from Filmtools. In our DVD Program, we used three basic set ups:

1. Composite Components Digital Blue Screen (12x12) with their blue spike tubes and FloCo lighting units 2. Composite Components Digital Green Screen with Kino Flo Image 80s (Tungsten 3200K) 3. Composite Components Video Blue Paint on a cove with Kino Flo Images 80s (Tungsten 3200K)

Paints: Digital Green and Digital Blue Paints are available Here at Filmtools.

Support Materials: Support materials can be purchased from Filmtools. When laid flat or perpendicular to the blue/green screen, Rosco 3931 Rigid Silver can add "extra" screen without the addition of more screen, space or lights by reflecting the blue/green screen. Rigid Silver can be positioned under an actor against a blue/green screen providing a blue/green walking surface.

This type of set up gives you the best separation of the foreground and the blue or green background. However, there is no interaction with the ground and reflections will have to be rotoscoped out. When shooting in a cove environment, the lighting must be consistent (such as all tungsten Kinoflos) and cannot create the same degree of separation. One benefit the cove has is that the shadows and floor interaction you wind up with may be useful for the composite.

Shooting on a Blue Screen or Green Screen Cove:

The object of the cove is to present a shooting environment where you can photograph the subject walking around on the floor and avoid a sharp line or edge where the floor meets the wall.

If you are shooting on a cove then you will need only one type of lighting to light both the screen and the subject. If you are lighting your subject with tungsten or 3200K lighting, then you are going to need to light the screen with 3200K tubes such as Kino-Flo 3200K fluorescents.

Shooting on a cove presents a more difficult challenge to light since you cannot use Digital Blue or Digital Green lights for optimum separation and you can't light as evenly.

Special thanks to Ultimatte for use of their stage and Ultimatte.

UPC Code: 881340000123