How to make key colour black in Gnuplot

Question

How can I make the key "symbols" black in colour when using palettes?

Answer 1

I think you cannot control this directly, here a workaround:

plot 'MOD1.dat' u 2:3:1 w p pt 7 ps 2 lt black, \
'MOD1.dat' u 2:3:1 w p pt 7 ps 2 lt palette notitle

So, we first plot the data without legend in black, then plot the data points but no legend. The nice thing about this approach is that there is no need to fix the x or y range.