Heritage Science

Table 3 Summary of most useful imaging and FORS markers for identification of ink colorants on sized paper

From: Creation and reference characterization of Edo period Japanese woodblock printing ink colorant samples using multimodal imaging and reflectance spectroscopy

Colorant	Imaging markers				FORS markers
Blue
Dayflower	VIL: luminesces		IRR: reflects	IRRFC: pink	590^a, 645^a
Indigo	VIL: no luminescence		IRR: reflects	IRRFC: pink	660^a
Prussian blue	VIL: absorbs		IRR: absorbs	IRRFC: dark blue/purple	600–1000^a, 2365^a
Red
Safflower	VIL/UVL: luminesces		IRRFC: yellow	UVRFC: red-brown	530^a
Sappanwood	VIL: luminesces UVL: absorbs		IRRFC: orange-red	UVRFC: brown	530^a
Madder	VIL/UVL: luminesces		IRRFC: orange-red	UVRFC: red-brown	510^a, 525^a
Cochineal	VIL/UVL: luminesces		IRRFC: orange-red	UVRFC: green	520^a, 555^a
Kermes	VIL/UVL: luminesces		IRRFC: orange-red	UVRFC: gray	520^a, 555^a
Lac	VIL/UVL: luminesces		IRRFC: orange-red	UVRFC: blue	520^a, 555^a
Red ochre	VIL/UVL: absorbs		IRRFC: orange-red	UVRFC: purple-brown	500^a, 650^a, 900^a
Vermilion	VIL/UVL: absorbs		IRRFC: yellow	UVRFC: purple-brown	590–600ⁱ
Red lead	VIL/UVL: absorbs		IRRFC: yellow	UVRFC: red	565ⁱ
Yellow
Flavonoids*	VIL: no luminescence		UVL: absorbs	UVRFC: brown	~ 460ⁱ
Amur cork tree	VIL: luminesces		UVL: luminesces	UVRFC: orange	440–450^a, ~ 495ⁱ
Gardenia	VIL: luminesces		UVL: luminesces	UVRFC: pink	450^a, 485^a, 460ⁱ, 510ⁱ
Gamboge	VIL: no luminescence		UVL: absorbs	UVRFC: orange	440–450^a, ~ 495ⁱ
Turmeric	VIL: luminesces		UVL: luminesces	UVRFC: pink	440–450^a, ~ 495ⁱ
Yellow ochre	VIL: no luminescence		UVL: absorbs	UVRFC: pink	500^a, 650^a, 900^a
Orpiment	VIL: no luminescence		UVL: absorbs	UVRFC: pink	485ⁱ

Flavonoid yellows include rice plant, pagoda tree, mountain peach, and Toringo crabapple which do not luminesce with the exception of pagoda tree
^aAbsorption
ⁱInflection point

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