From Directorforum Collaboration Wiki
--result.red := a.red;
--result.green := a.green;
--result.blue := b.blue;
-- ******* blue mode *************
on BlueBlendMode (image1, image2)
theWidth = image1.width - 1
theHeight = image1.height - 1
theImage = image(theWidth + 1, theHeight + 1, 32)
repeat with x = 0 to theWidth
repeat with y = 0 to theHeight
theColour1 = image1.getPixel(point(x,y))
theColour2 = image2.getPixel(point(x,y))
theNewColour = color(0,0,0)
theNewColour.red = theColour1.red
theNewColour.green = theColour1.green
theNewColour.blue = theColour2.blue
theImage.setPixel(point(x, y), theNewColour)
end repeat
end repeat
return theImage
end