[RGMOfficial]

Did some changes on the code, and actually...

the rainbowing looks great and realistic.

function dpc_makerainbow(clip C, float "sat")
{
    sat  = Float(Default(sat, 1))
    
    color_sat = int(50000*sat)
	
    C
    AddGrainC(var=0,uvar=color_sat,hcorr=.9,vcorr=.4,seed=1)
}

Also, i added a new preset, that i've been using with the original plugin. It's the preset used on the screenshot below.

## @ preset - choices:
##            "mild"     - minimal effect
##            "medium"   - softer chroma; a little added noise
##            "heavy"    - very soft & noisy
##            "strong"   - like medium but more so
##            "bigdot1"  - larger dots #1
##            "bigdot2"  - larger dots #2
##            "bigdot3"  - larger dots #3
##            "betacam"  - Analog formats - Betacam
##            empty string ("") defaults to "medium";
##            unrecognized values raise an error.