Equivalent of After effects Pre multiply on white.


#1

What is the Fusion equivalent of After Effects Pre-multiplied - Matted with Color on importing.

Essentially I have a 16bit .exr image that was rendered on a white background - in AE you choose the colour on import the image was rendered on & it pre-multiplies the colour therefore removing the Jaggy White edges that are within the images aliased edges.


#2

you have to build it with some nodes by your self, this sounds at the start maybe scary but then its more powerful then a pure unpremult by white.
with this method you can unpremult by any color or even with image BGs (as long as you have a cleanplate)

{
	Tools = ordered() {
		SubstractFGBG = ChannelBoolean {
			NameSet = true,
			Inputs = {
				Operation = Input { Value = 2, },
				Background = Input {
					SourceOp = "PipeRouter1",
					Source = "Output",
				},
				Foreground = Input {
					SourceOp = "MultiplyBGA",
					Source = "Output",
				},
				Comments = Input { Value = "Substract BG from FG", },
			},
			ViewInfo = OperatorInfo { Pos = { 813.815, 390.285, }, },
		},
		ChannelBooleans4 = ChannelBoolean {
			CtrlWZoom = false,
			Inputs = {
				ToRed = Input { Value = 4, },
				ToGreen = Input { Value = 4, },
				ToBlue = Input { Value = 4, },
				Background = Input {
					SourceOp = "SubstractFGBG",
					Source = "Output",
				},
				Foreground = Input {
					SourceOp = "PipeRouter1",
					Source = "Output",
				},
				Comments = Input { Value = "bring back original alpha", },
			},
			ViewInfo = OperatorInfo { Pos = { 982.929, 397.106, }, },
		},
		MultiplyBGA = ChannelBoolean {
			NameSet = true,
			Inputs = {
				Operation = Input { Value = 6, },
				Background = Input {
					SourceOp = "Background1_1",
					Source = "Output",
				},
				Foreground = Input {
					SourceOp = "InvertAlpha",
					Source = "Output",
				},
				Comments = Input { Value = "multiply BG with inverted alpha, to matte out the FG", },
			},
			ViewInfo = OperatorInfo { Pos = { 625.969, 393.695, }, },
		},
		Note2 = Note {
			Inputs = {
				Comments = Input { Value = "here is the BG Image, look that is has the same dimensions like your footage", },
			},
			ViewInfo = StickyNoteInfo {
				Pos = { 351.13, 270.919, },
				Flags = {
					Expanded = true,
				},
				Size = { 196, 179.3, },
			},
		},
		InvertAlpha = ChannelBoolean {
			NameSet = true,
			Inputs = {
				Operation = Input { Value = 10, },
				ToRed = Input { Value = 3, },
				ToGreen = Input { Value = 3, },
				ToBlue = Input { Value = 3, },
				Background = Input {
					SourceOp = "PipeRouter1",
					Source = "Output",
				},
				Comments = Input { Value = "Invert the original alpha", },
			},
			ViewInfo = OperatorInfo { Pos = { 636.471, 307.297, }, },
		},
		Background1_1 = Background {
			Inputs = {
				Width = Input { Value = 2048, },
				Height = Input { Value = 1556, },
				["Gamut.SLogVersion"] = Input { Value = FuID { "SLog2", }, },
				TopLeftRed = Input { Value = 1, },
				TopLeftGreen = Input { Value = 1, },
				TopLeftBlue = Input { Value = 1, },
				Gradient = Input {
					Value = Gradient {
						Colors = {
							[0] = { 0, 0, 0, 1, },
							[1] = { 1, 1, 1, 1, },
						},
					},
				},
			},
			ViewInfo = OperatorInfo { Pos = { 393.193, 397.106, }, },
		},
		PipeRouter1 = PipeRouter {
			ViewInfo = PipeRouterInfo { Pos = { 646.703, 231.13, }, },
		},
		Note1 = Note {
			Inputs = {
				Comments = Input { Value = "Image with BG goes here", },
			},
			ViewInfo = StickyNoteInfo {
				Pos = { 722.869, 201.573, },
				Size = { 196, 179.3, },
			},
		},
	},
}