# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'zeta.1.png'
set grid nopolar
set grid xtics nomxtics ytics nomytics noztics nomztics nortics nomrtics \
 nox2tics nomx2tics noy2tics nomy2tics nocbtics nomcbtics
set grid layerdefault   lt 0 linecolor 0 linewidth 0.500,  lt 0 linecolor 0 linewidth 0.500
set key fixed left top vertical Right reverse enhanced autotitle nobox
set samples 999, 999
set style data lines
set xzeroaxis
set title "Real and imaginary parts of ζ(s) along the critical line real(s) = 1/2" 
set xrange [ 5.00000 : 50.0000 ] noreverse
set yrange [ -3.00000 : 4.00000 ] noreverse
NO_ANIMATION = 1
save_encoding = "utf8"
plot real(zeta( 0.5 + I*x )) lt 4 lw 3 title "real( ζ(½ + ix) )",      imag(zeta( 0.5 + I*x )) lt 6 lw 3 title "imag( ζ(½ + ix) )"