Blend

Blend[{col1,col2},x] gives a color obtained by blending a fraction 1-x of color col1 and x of color col2.

Blend[{col1,col2,col3,…},x] linearly interpolates between colors coli as x varies from 0 to 1.

Blend[{{x1,col1},{x2,col2},…},x] interpolates to give coli when x=xi.

Blend[{col1,col2,…},{u1,u2,…}] blends all the coli, using fraction ui of color coli. 

Blend[{image1,image2,…},…] blends pixel values of 2D or 3D images imagei.

Please visit the official Wolfram Language Reference for more details and examples on core symbols.