Highly　homogeneous　surface-enhanced　Raman　scattering　(SERS)　substrates　were　produced　on　the　centimeter　scale　by　annealing　solution-processed　gold　nanoparticles　into　plasmonic　nanoislands.　The　average　size　and　separation　of　the　nanoislands　are　controlled　by　tuning　the　annealing　temperature.　SERS　measurements　yield　a　global　enhancement　factor　as　large　as　10(7)　over　an　area　of　2　x　2　cm(2)　for　samples　annealed　at　temperatures　ranging　from　150　to　200　degrees　C.　Spectral　＂mapping＂　of　the　SERS　signal　shows　a　homogeneous　distribution　of　hotspots　with　high　contrast　over　the　entire　substrate.　The　relative　standard　deviation　of　the　SERS　signal　is　less　than　5.4%　over　an　area　of　50　x　50　mu　m(2).　Theoretical　simulations　show　strong　dependence　of　the　near-field　electromagnetic　enhancement　on　the　size　and　the　separation　gap　of　the　gold　nanoislands.　Both　average　gap　size　and　average　nanoisland　size　increase　with　an　increase　in　annealing　temperature.　Intensive　plasmonic　coupling　between　the　adjacent　gold　nanoislands　leads　to　broadband　resonance　for　samples　annealed　at　150　and　200　degrees　C;　thus,　the　laser　excitation　within　the　spectrum　of　plasmon　resonance　at　633　or　785　nm　produced　significantly　enhanced　SERS　for　4-mercaptopyridine　molecules　modified　on　the　gold　nanoislands.