FORS analysis of Ukiyo-e prints: Difference between revisions
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FORS reflectance spectra can readily distinguish between three common blue colorants used in Japanese woodblock prints (dayflower, indigo, and Prussian blue). Spectra for the three common blues are shown below, along with spectra of each blue from a print. The paper used in the prints typically has a slight yellowish tint, thus for the FORS analysis, an area of bare paper is used to acquire a background spectrum, which is then subtracted from the spectrum of the colored area. In principle, this gives spectra which should be more directly comparable between standards prepared in the lab and areas on prints. | FORS reflectance spectra can readily distinguish between three common blue colorants used in Japanese woodblock prints (dayflower, indigo, and Prussian blue). Spectra for the three common blues are shown below, along with spectra of each blue from a print. The paper used in the prints typically has a slight yellowish tint, thus for the FORS analysis, an area of bare paper is used to acquire a background spectrum, which is then subtracted from the spectrum of the colored area. In principle, this gives spectra which should be more directly comparable between standards prepared in the lab and areas on prints. | ||
{| class="wikitable" style="display: inline-table;font-size:90%;text-align:center;width:15%" | |||
File:Dayflower FORS MFA.png|300px| FORS spectrum of Dayflower ref | |File:Dayflower FORS MFA.png|300px|FORS spectrum of Dayflower ref | ||
File:Indigo FORS MFA.png|thumb| FORS spectrum of Indigo reference | |- | ||
File:Prussian blue FORS MFA.png|thumb| FORS spectrum of Prussian blue reference | | | ||
File: | [[File:1126691-Pt5-FORS.jpg|200px]]<br>[[Eisen, Geisha at Night under Plum Blossoms, 11.26691-2|Pt 5: Printed<br>Keisai Eisen, 11.26691-2]] | ||
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|File:Indigo FORS MFA.png|thumb|FORS spectrum of Indigo reference | |||
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[[File:1126691-Pt5-FORS.jpg|200px]]<br>[[Eisen, Geisha at Night under Plum Blossoms, 11.26691-2|Pt 5: Printed<br>Keisai Eisen, 11.26691-2]] | |||
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{| class="wikitable" style="display: inline-table;font-size:90%;text-align:center;width:15%" | |||
|File:Prussian blue FORS MFA.png|thumb|FORS spectrum of Prussian blue reference | |||
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[[File:21.9254-Pt3.jpg|200px]]<br>[[Shigenobu I, Urashima Tarô, from the series A Set of Five Examples of Longevity, 21.9254|Pt 3: Printed<br>Yanagawa Shigenobu I, 21.9254]] | |||
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The table below shows reference FORS spectra for many of the Edo period colorants, organic as well as inorganic. Spectra from some mixtures are also shown. Data was acquired over a period of time, and the displays of results are not consistently formatted but are representative of the colorants. It should be stressed that for various reasons, these spectra may not exactly match spectra prepared and analyzed by other researchers, and also will not necessarily match spectra of the same colorants in prints. | The table below shows reference FORS spectra for many of the Edo period colorants, organic as well as inorganic. Spectra from some mixtures are also shown. Data was acquired over a period of time, and the displays of results are not consistently formatted but are representative of the colorants. It should be stressed that for various reasons, these spectra may not exactly match spectra prepared and analyzed by other researchers, and also will not necessarily match spectra of the same colorants in prints. | ||
Revision as of 14:14, 19 July 2025
Overview
FORS reflectance spectra can readily distinguish between three common blue colorants used in Japanese woodblock prints (dayflower, indigo, and Prussian blue). Spectra for the three common blues are shown below, along with spectra of each blue from a print. The paper used in the prints typically has a slight yellowish tint, thus for the FORS analysis, an area of bare paper is used to acquire a background spectrum, which is then subtracted from the spectrum of the colored area. In principle, this gives spectra which should be more directly comparable between standards prepared in the lab and areas on prints.
| 300px|FORS spectrum of Dayflower ref |
| thumb|FORS spectrum of Indigo reference |
| thumb|FORS spectrum of Prussian blue reference |
The table below shows reference FORS spectra for many of the Edo period colorants, organic as well as inorganic. Spectra from some mixtures are also shown. Data was acquired over a period of time, and the displays of results are not consistently formatted but are representative of the colorants. It should be stressed that for various reasons, these spectra may not exactly match spectra prepared and analyzed by other researchers, and also will not necessarily match spectra of the same colorants in prints.
FORS Reference Spectra
| Blues | Greens | Yellows | Reds |
|---|---|---|---|
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Analysis
Greens were usually made from a combination of a blue and a yellow colorant, while purples were usually made from a combination of a blue and a red colorant. The blue colorants in these mixtures can usually be determined by FORS analysis. FORS is not usually useful for identifying yellow colorants but can sometimes be useful for the organic reds.