......just checked that tin foil info,,
yeah aluminum foil is 70-75 % reflective,
Flat yellow is 70-80%,
semi white gloss paint 75-80%,
flat(mat)white paint 85-95%,
reflective mylar 90-95%,
These figure are from my Grow bible, I dont have a light mointer/meter to test them out but I kinda trust it..
take it easy,,,