Table 1.

Investigated samples and thickness of the layers.

	layer thickness (µm)
sample	top (red ochre)	bottom (phthalocyanine blue)
S1	21	40–45
S2	24	40–45
S3	27	40–45
S4	43	40–45
S5	45	40–45
S6	56	40–45
S7	73	40–45
S8	121	40–45