Diff, Minus, Multiply, and Plus Nodes

These four nodes composite two images based on the pixel values of two input nodes as specified in the following descriptions. These nodes do not require user modification of parameters; therefore their node panels feature an Info Tab only.

The two required inputs to the Diff, Minus, Multiply, or Plus node must have the same number of channels, however, each input image can consist of from one to 10 channels.

Tip:
To adjust the number of channels in an image, use the Channel Swap node.

The order in which the inputs are connected to the nodes (i.e., top or bottom) is irrelevant, with the exception of the Minus node, as described below.

Diff Node

The Diff node calculates the difference between the A and B images. The difference is the absolute value of the result of subtracting image B from image A. The Diff node accepts two inputs and performs the following computation:

R = |A - B|

For example:

200 - 50 = 150
50 - 250 = 200
0.5 - 0.25 = 0.25
0.25 - 0.5 = 0.25

Minus Node

The Minus node subtracts the values of the B image from the values of the A image. The Minus node accepts two inputs and performs the following computation:

R = A - B

The Minus node is similar to the Diff node; however, the Minus node will clamp integer values at zero (floats are not clamped).

For example:

200 - 50 = 150
50 - 250 = 0
0.5 - 0.25 = 0.25
0.25 - 0.5 = -0.25

Multiply Node

The Multiply node multiplies the values of the A image by the values of the B image. Multiply accepts two inputs and performs the following computation:

R = A * B

The Multiply node will clamp integer values at maximum (255 for 8-bit; 65535 for 16-bit).

For example:

20 * 10 = 200
30 * 10 = 255 (if 8-bit)
0.5 * 1.0 = 0.5
10.0 * 100.0 = 1000.0 (no clamping on floats)

Plus Node

The Plus node adds the values of the B image to the values of the A image. The Plus node accepts two inputs and performs the following computation:

R = A + B

The Plus node will clamp integer values at Vmax.

For example:

200 + 10 = 210
200 + 60 = 255 (if 8-bit)
65000 + 10 = 65010
65000 + 7000 = 65535 (if 16-bit)
0.5 + 0.2 = 0.7
0.5 + 5 = 5.5 (no clamping on floats)




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