Stock futures traded in a narrowly mixed range ahead of Tuesday’s start of trade as investors took in a raft of earnings reports, an international deal with Iran and weak June retail sales data. Dow futures were down a slender 3.7 points. Nasdaq 100 futures were 7.2 points above fair market value and S&P 500 futures were up a scant 0.6 points. Small caps lagged, with Russell 2000 futures down 1.5 points.