Thermal transfer foil for producing a true color image, process for producing a true color image, and true color image

A process for producing a color image comprising:

• providing one or more thermal foils having an effect pigment layer and a carrier foil, the effect pigment layer comprising effect pigments;
• and
• applying subareas of the effect pigment layer of at least one of the one or more thermal transfer foils to a first surface of a substrate using one or more thermal transfer printheads, whereby effect pigments having different optical effects and/or orientations are transferred from the subareas to form two or more halftone dots on the substrate, said two or more halftone dots being formed in such a way that additive and/or subtractive color mixing of the two or more halftone dots form the color image,
• wherein the color image consists of a multiplicity of color domains which, when illuminated and viewed in reflected light or in transmitted light show a color, and
• wherein the at least two halftone dots are formed in at least 10% of the color domains.