This is the 14735th most frequent Russian word.
пигментных
"Pigmental" or "of pigments."
Here, "пигментных" is used as an adjective describing spots ("пятен") that are pigment-related — caused or associated with pigments.
Врач объяснил наличие пигментных пятен на коже пациента.
The doctor explained the presence of pigment spots on the patient's skin.
Here, "пигментных" acts as an adjective modifying paints ("красок") that contain pigments.
Процесс смешивания пигментных красок требует особой точности.
The process of mixing pigment paints requires special precision.
In this sentence, "пигментных" modifies images ("изображений") that are formed with pigments, emphasizing the material or substance related aspect.