Unity Script Reference:
Legacy Documentation: Version 4.3.0
BlendOp
Description

Blend operation.

The blend operation that is used to combine the pixel shader output with the render target. Note that the logical operations are only supported in Gamma (non-sRGB) colorspace, on DX11.1 hardware running on DirectX 11.1 runtime.
Variables
Add Add (s + d).
Subtract Subtract.
ReverseSubtract Reverse subtract.
Min Min.
Max Max.
LogicalClear Logical Clear (0).
LogicalSet Logical SET (1) (D3D11.1 only).
LogicalCopy Logical Copy (s) (D3D11.1 only).
LogicalCopyInverted Logical inverted Copy (!s) (D3D11.1 only).
LogicalNoop Logical No-op (d) (D3D11.1 only).
LogicalInvert Logical Inverse (!d) (D3D11.1 only).
LogicalAnd Logical AND (s & d) (D3D11.1 only).
LogicalNand Logical NAND !(s & d). D3D11.1 only.
LogicalOr Logical OR (s | d) (D3D11.1 only).
LogicalNor Logical NOR !(s | d) (D3D11.1 only).
LogicalXor Logical XOR (s XOR d) (D3D11.1 only).
LogicalEquivalence Logical Equivalence !(s XOR d) (D3D11.1 only).
LogicalAndReverse Logical reverse AND (s & !d) (D3D11.1 only).
LogicalAndInverted Logical inverted AND (!s & d) (D3D11.1 only).
LogicalOrReverse Logical reverse OR (s | !d) (D3D11.1 only).
LogicalOrInverted Logical inverted OR (!s | d) (D3D11.1 only).