Dear RupertPupkin's and dear Gödel
Thank you very much both of you for your helpful answers
which solved my problem.
As RupertPupkin's indicated I typed
setterm -background white -foreground black
And I obtained the desired colors.
As Gödel indicated I added the following line to ~/.bash_profile
in order to have these colors permanently.
echo -en '\E[0;30;47m\E'
Thank you very much for your help.