Enroute D-Side Controller witnessed loss of separation event; claiming the Data Block size used by the R-Side made observation of the display and assistance very difficult.

Narrative

I was D-Side off line coordinating a change of destination with TMU via ring line and point out traffic to approach via shout line. I was using URET and DCRUD to obtain aircraft information and looking at our overhead display to see arrivals coming into the sector not yet displayed on monitor. The R-Side Data Block text is too small to be reliable from D-Side. During this coordination; R-Side took hand-off of Air Carrier Y from low altitude sector at FL290 requesting FL380. He climbed Air Carrier Y northbound to FL320 not seeing traffic at FL300 westbound who was in conflict. R-Side turned Air Carrier Y 50 degrees right; pilot read back 15 right; R-Side corrected him. Separation was lost; R-Side put up a J-Ring on Air Carrier X; showing approximately 2 1/2 miles and 200 FT. When I was finishing coordination; I saw Conflict Alert had activated and it appeared that Air Carrier Y was turned away from Air Carrier X. Recommendation: use data block text size so sector team can be effective. Scan entire traffic area. It is not uncommon to do a very complete scan around an aircraft but not in the immediate proximity. R-Side is low time CPC and has the attitude that he knows it all; can not learn anything more; and overall full of himself. I hope this gives him some humility.