# The Laboratory Dates the Material, Not the Object > Radiocarbon put the wax of the Bode Museum's Flora bust in the Renaissance. The bust was made in the nineteenth century, and the wax came from a whale. A physical date is a date for a substance, and the substance has a history of its own. > The Study - 2026-09-07 > Canonical HTML: https://iconotheca.com/study/the-laboratory-dates-the-material-not-the-object/ ## Key points - The raw radiocarbon dates for the wax of the Bode Museum's Flora bust run from 340 to 395 years before present, which read naively would place it in the Renaissance and support the attribution to Leonardo. The wax is spermaceti, from a sperm whale, and marine carbon is already old when the animal eats it. Corrected, the bust is nineteenth-century. - Two wax reliefs made by Richard Cockle Lucas in 1848 and 1850, of documented date, returned raw dates of 380 to 420 years before present in the same study. Objects known to be about 170 years old measured as roughly 400. That is the size of the trap. - The Cleveland Museum of Art has moved radiocarbon results into the date field itself on four silks catalogued in the Buyid style. One dates to 899 to 1160 and is genuine. Two date to after 1950. - The first radiocarbon date published for the Grolier Codex was taken from one of eight blank sheets of fig bark paper found with it, not from a painted page. Blank ancient paper is the classic forger's material, and the source that reports the later dates says in the same sentence that they date the paper and not the images upon it. - For a cast bronze the physical clock and the making are the same event. Thermoluminescence zeroes when clay is fired, and the clay core of a lost-wax bronze is fired during the casting, which is why the Metropolitan's bronze horse could be cleared after being publicly called a forgery in 1967. - The physical date is often much less precise than the stylistic one it is asked to check. Thermoluminescence put the Metropolitan horse anywhere between about 500 and 50 BC with equal probability, a band of 450 years, against a catalogue date of 480 to 470. - Gold and stone have no clock at all. The Louvre dates the Tiara of Saitaphernes to the nineteenth century and names its maker, and neither fact came from a laboratory. ## A physical date is a date for a substance, and substances have their own histories ## The Flora bust dated to the Renaissance because its wax came from a whale ## Four silks, one method, and a museum that rewrote its own date fields ## A Maya codex was first dated from a blank sheet ## For a cast bronze the clock and the making are the same event ## The physical date is frequently less precise than the one it is checking ## An ageing test is only as good as the claim that nature alone can do it ## Gold and stone carry no clock, and the date comes from the archive instead ## How to read a scientific date ## Why this archive is free to read A number from a laboratory feels like the end of an argument and it is usually the start of one, because the number belongs to a material and somebody still has to show that the material and the object have the same history. The Flora bust makes the point at full strength: competent measurement, real numbers, and a raw result four hundred years too early because the wax swam. Cleveland shows the method working exactly as it should, separating one genuine silk from three that are not and printing the result where a date would go. So read the sample before the result, ask what offset applies, compare the width of the answer to the width of the question, and where the material carries no clock at all, stop looking for one and go to the archive. ## Questions **Does radiocarbon dating tell you when a work of art was made?** It tells you when the organism that supplied the material stopped taking in carbon: when the tree was felled, the flax cut or the animal killed. Getting from that to the date of the object is an argument, not a measurement, and it fails whenever the maker used material that was already old or came from the sea. **Why did radiocarbon put the Bode Museum's Flora bust in the Renaissance at first?** Because the bust is made mainly of spermaceti, the wax from a sperm whale's head, and marine carbon is depleted relative to the atmosphere, so a marine animal measures older than it is. Raw dates on the wax run 340 to 395 years before present; corrected for the marine reservoir effect the 2021 study in Scientific Reports places the bust in the nineteenth century. Two wax reliefs by Richard Cockle Lucas of documented 1848 and 1850 date returned raw dates of 380 to 420 in the same study. **What does a museum mean when it dates something after 1950?** It means the radiocarbon signature includes the surge in atmospheric carbon-14 caused by nuclear weapons testing, which began in the mid-1950s. The Cleveland Museum of Art gives that date for two silks catalogued as being in the style of the Buyid period, 1985.59 and 1982.23, in the date field of their public records. **Can you radiocarbon date a gold object?** No. Gold contains no organic carbon and no firing event, so there is nothing to measure. The Louvre dates the Tiara of Saitapharnes to the nineteenth century and names Israel Rouchomowsky as its maker on the strength of testimony and documents, not laboratory analysis. **Is thermoluminescence different from radiocarbon in this respect?** For a cast bronze, yes. Thermoluminescence resets when clay is fired above roughly five hundred degrees, and the clay core of a lost-wax bronze is fired by the casting itself, so the clock and the making coincide. That is how the Metropolitan Museum's bronze horse, publicly called a forgery in 1967, was shown to have been cast in antiquity. **How precise are these dates?** Often much less precise than the catalogue date they are checking. Thermoluminescence placed the Metropolitan horse between about 500 and 50 BC with equal probability across that range, a band of 450 years, against a published date of 480 to 470 BC. ## Sources - [1] Ina Reiche, Lucile Beck and Ingrid Caffy, New results with regard to the Flora bust controversy: radiocarbon dating suggests nineteenth century origin, Scientific Reports 11, article 8249, published 15 April 2021. Read in full for the identification of the wax as spermaceti, the marine reservoir correction, the raw wax dates of 340 to 395 BP for the bust and 380 to 420 BP for the two dated Lucas reliefs, the 110 to 195 BP dates on the filling materials, and Freundlich's earlier 290 plus or minus 40 BP result. - [2] Cleveland Museum of Art, Open Access API, collection records for accessions 1975.45, 1954.780, 1982.23 and 1985.59. Read for the date fields giving radiocarbon results at 95 per cent probability and for the culture lines reading in the style of the Buyid period. - [3] Cleveland Museum of Art, collection record 1954.780, Tomb Cover. The museum's own public page for the record subject illustrated here. - [4] Donna Yates, Grolier Codex, Trafficking Culture encyclopedia, University of Glasgow. Read in the raw page for the eight blank sheets of fig bark paper, the AD 1230 plus or minus 130 date taken from one of them, the later dates of AD 1257 plus or minus 110 and 1212 plus or minus 40 with the qualification that these are the date of the paper and not the images upon it, and the arguments from Maya blue, gypsum ground and sketch lines. - [5] Kate C. Lefferts, Lawrence J. Majewski, Edward V. Sayre and Pieter Meyers, Technical Examination of the Classical Bronze Horse from the Metropolitan Museum of Art, Journal of the American Institute for Conservation, vol. 21, no. 1. Read in the raw page for Noble's December 1967 announcement, the statement that the dating clock is set to zero at firing, Zimmerman's age of 2250 plus or minus 210 years BP from three zircon grains, his quoted 500 BC to 50 BC formulation, the earlier quartz estimates of 2,000 and 5,500 years, and the 15 rads deposited by the museum's own radiography. - [6] Trafficking Culture, case study: Getty Kouros, University of Glasgow. Read for the de-dolomitization argument, the demonstration that magnesium can be removed from dolomitic marble artificially, the 1992 Athens colloquium at which nineteen invited experts reached no consensus, and the museum label reading Greek, about 530 BC, or modern forgery. - [7] Musee du Louvre, collection record for the tiare de Saitapharnes, inventory MNC 2135 and Bj 2357. Read for the date of 1800 to 1900, the attribution to Rouchomowsky, Israel, orfevre, 1860 to 1934, the material and techniques, the inscription catalogued as modern, the 1896 purchase, and the current location given as non expose.