LTSS BTWN DEPARTING ACFT OFF EWR; LCL CTLR APPLIED VISUAL SEPARATION TOO LATE.

Narrative

I WAS WORKING LCL CTL AT EWR. I TOLD SMT X TO TAXI INTO POS AND HOLD RWY 29; ON DEP; TURN R HDG 230. (I ACTUALLY MEANT TURN L; BUT I DID NOT CATCH MY ERROR). I RECEIVED ACKNOWLEDGEMENT. I CLRED SMT X FOR TKOF AND PUT THE NEXT DEP; MLG Y INTO POS AND HOLD RWY 29; ON DEP. TURN R HDG 300. I RECEIVED ACKNOWLEDGEMENT. I LOOKED FOR SMT X AND DIDN'T SEE HIM. I FIGURED HE'D CRANKED IT AROUND THE TWR AND WAS OBSCURED FROM VIEW BY THE TWR ROOF. I DETERMINED SMT X WAS NOT WHERE MLG Y WOULD BE AND I CLRED MLG Y FOR TKOF. I TOLD SMT X TO CONTACT NEW YORK DEP HDG 230. A FEW SECONDS LATER HE ASKED TO VERIFY HDG 320. I RESTATED '230'. HE ACKNOWLEDGED. DOUBT IS NOW RAISED IN MY MIND ABOUT EXACTLY WHAT SMT X IS DOING SO I TELL HIM THAT I LOST SIGHT OF HIM AND TO SAY POS NOW. HE SAID HE WAS ON A 320 HDG AND THEN I SPOTTED HIM AS DESCRIBED; ON A 320 HDG. I TOLD HIM TO CONTINUE A L TURN AND ADVISED HIM OF THE MLG Y OFF HIS L; CLBING OUT OF ABOUT A THOUSAND; AND DID HE SEE HIM. HE STATED AFFIRMATIVE AND I TOLD HIM TO CONTACT NY DEP. WHEN I REESTABLISHED VISUAL CONTACT WITH HIM; I REALIZE THERE IS ROOM TO GET HIM ON COURSE IN FRONT OF THE MLG Y WITHOUT DANGER OF COLLISION SO I APPLIED VISUAL SEPARATION IN ACCORDANCE WITH FAA MANUAL 'ATC'; 7110.65F; CHAPTER 7; PARAGRAPH 7-10; 'VISUAL SEPARATION'; PART A; 1 AND 2. I COORD WITH DEP CTL ABOUT SMT X AND MLG Y. BY NOW; SMT X IS S OF MLG Y FLT PATH SO I TOLD MLG Y TO CONTACT NY DEP. HE ASKED ABOUT THIS TFC 'STRAIGHT AHEAD'; AND I ADVISED HIM THAT VISUAL SEPARATION WAS BEING APPLIED. HE ACKNOWLEDGED.