Mask a label using chroma key masking
 
 
 
  1. In the Stencil texture Control Window, click HSV Color Key to display the HSV Color Key parameters.
  2. Set Key Masking ON.
  3. Click the color field beside Color Key to open the Color Editor.
  4. Click the Grab button in the Color Editor. The mouse pointer becomes an eye dropper.
  5. Move the eye dropper over the Multi-lister, and click the on the background color of the Image texture. All areas of the Image texture that have this color are now transparent (masked) and the shader color is visible in these areas.

    To mask a range of colors, adjust the Hue Range, Sat Range, Val Range, and Threshold settings.

    To invert the mask, set Positive Key ON. Only the color (or range of colors) specified in the HSV Color Key parameters are visible, instead of masked.

When you are finished masking the label, click the arrow in the bottom right corner of the shader swatch to hide the Stencil texture and the Image file (and the Mask file if there is one).

To preview the label map and mask do a full render.

To position the texture on a surface, see Use 3D mapping to position a texture on a surface or Use 2D mapping to position a texture on a surface.