Disclosed herein is a method for labelling a portion of a device, said method comprising the steps of providing a first substrate layer of a transparent or translucent material, depositing a first coloured material onto said first substrate layer in a labelling portion of said layer, thereby obtaining a labelling item, and coupling said labelling item to the device. The method is particularly suitable for producing labelled stretchable devices such as soft body-implantable devices for sensing a physiological signal and/or stimulating an electrical and/or pharmacological activity of a body tissue or organ in a subject.