In calc I have currence entries with in corect colours.
Positive value are shown in BLUE
Negative valus are shown ib GREEN.
I have tried to change colours theses seen to be accepted but are ingored. please help.
Please detail your LibreOffice version and Os. How do you set up the colors?
If you are not able to change the colors, you seem to use Conditional Formatting. Thus check Format -> Conditional -> Manage ...