• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Chapter 13. Super-imposing Clips > Using Multiply and Screen Keys

Using Multiply and Screen Keys

The multiply and screen keys calculate the clip's transparency based on luminance values taken from both the clip and the underlying image. Multiply determines transparency values by averaging the product of the luminance values of the clip and the underlying image. As a result, the clip becomes more transparent where brighter areas of both clips correspond. Black areas of the clip remain opaque (Figure 13.27). Screen uses inverse luminance values in its calculation. Therefore, Screen makes the clip more transparent where darker areas of both clips correspond. Pure white areas of the clip are always opaque (Figure 13.28). But the best way to understand these keys is to compare them.

Figure 13.27. Multiply makes the clip more transparent where the bright areas of the clip and the underlying image correspond. In this image, the clouds show through more in areas where the statue's highlights and the clouds overlap.



PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint