A process for shading white paper characterized in that a mixture comprising at least one direct dye or pigment and at least one optical brightener is used, is claimed as well as the mixture and the paper dyed with this method. Needles are provided for casting an image on one at least one of the image planes, the needles being pivotably mounted at a further pivot point different from the pivot point of the pointing device and being constrained for movement in plane defined by the pivot point, the further pivot point and by the pointing device. The whole cap is made of silicone, which is a material of flexibility and elasticity. The subject methods employ an algorithm that employs a different dispersity measure depending on whether the signal features are weaker or stronger.