Flash Effect

Flash is a flexible tool that has many applications. It's used to adjust colors, to control the picture brightness, to perform dynamic video effects such as flash and fade, and so on.

Flash duration [backwards]
initial-luminosity of red of green of blue
finish-luminosity of red of green of blue
median of red of green of blue
swing of red of green of blue
front-quality of red of green of blue
tail-quality of red of green of blue

Remarks
Duration is a positive number that doesn't exceed 15000. It defines how long the effect lasts. Backwards keyword reverses the effect forcing it to perform backwards from the end.
Initial-luminosity defines initial gain factors for each color channel. Gain factor is a positive number, 1.0 means no color change, zero totally stifles a color to blackness, a value above 1.0 gains up brightness. When the effect finishes, the gain factors are set to values of the finish-luminosity parameter.
Median parameter sets the moment of luminosity splash separately for red, green and blue channels. Swing specifies the extent of color variation. Positive values gain up the luminosities, negative ones stifle the colors.
Quality defines the sharpness of the color variation. It's usually trapped in range between 0.5 and 0.0001. Qualities of the front of splash and its tail are parameterized separately. For example it's possible to create an effect where brightness of let's say red is instantly set to maximum and then slowly downs to normal. In this case quality of the front must be much greater than of the tail.
Example
# In this example a "bloody" flash 
# effect happens at the end of 
# "Kabala Magnet" painting.
Scene once
  Show 5376
  Flash 400
    initial-luminosity 1 1 1
    finish-luminosity  0.3 0 0
    median 30 30 30
    swing 1 1 1
    front-quality 0.1 0.1 0.1
    tail-quality 0.005 0.05 0.05
End
...now shortly about script syntax, comments