I am trying to change the color of the background through the use of plscolbg.
I am using PLplot with Cairo and GTK, the whole program being coded in Ocaml and thus using Ocaml bindings.

I use the code from this example: http://plplot.svn.sourceforge.net/viewvc/plplot/trunk/examples/ocaml/xgtk_interface.ml?view=markup.
I juste want to change the background color from black, as in default, to white.

In order to do this, I use the following line: "plscolbg 255 255 255;".
As it is indicated on this page (http://techlogbook.wordpress.com/2009/12/11/changing-background-and-front-color-in-plplot-library/), I added this command just before the line: "let plcairo = plinit_cairo ~clear: true (plot_width, plot_height) plimagecairo in"
My guess being that plinit_cairo was actually calling plinit and thus I needed to change the background before.
However, the background color does not change.
Does anyone have a idea of the cause of this problem ?

Thanks in advance for your time.

Johan Mazel