I am trying to get a Glow effect in the compositor. I added Node Math (Add)
And now my render is black&white. What am I doing wrong?
Like 3pointedit already said in his comment, the problem is the math node.
An option to solve your problem is using the Seperate RGBA node for both pictures and use the math node for each channel seperately. Afterwards combine the channels again with the Combine RGBA node.
Or, again referring to 3pointedit, use the Color Mix Node.