When mixing Caligo Relief Printing Inks (although this also applies to other brands), we can choose between adding Extender or Opaque White when we want a paler colour. They produce quite different results. Watch our video at the bottom of the page or read on.
Extender is a colourless ink. It will make colours more transparent which will allow the colours underneath to show through (this may be previous print layers or just the paper). You can mix paler shades without losing any of the luminosity of the ink.
You can use as much or as little extender as you like. More extender will create a paler, more transparent colour.
Adding opaque white will create a more pastel chalky shade. It will also make the ink more opaque: it will cover more of the colour underneath and start to show on darker coloured papers.