Quick follow-up: What is the order of the channels in the output image?
Assuming input is RGB image and output is 6 channels (as in OP) is the order:
Guess 1:
J1 = F1 * R
J2 = F2 * G
J3 = F3 * B
J4 = F4 * R
J5 = F5 * G
J6 = F6 * B
Or
Guess 2:
J1 = F1 * R
J2 = F2 * R
J3 = F3 * G
J4 = F4 * G
J5 = F5 * B
J6 = F6 * B