Two different identifiers
The selected Cotman Ultramarine is colour 660 in the maker range. PB29 is the pigment code on the maker’s product/chart record. A commercial colour number identifies a manufacturer’s named colour; it is not a universal pigment identifier shared across brands or product ranges.
A single-pigment field is still limited
PB29 appearing in the record does not disclose the full binder, preservative recipe or pigment concentration. Nor does it prove that every paint sold as Ultramarine contains the same formula. The site records the declared pigment field without measuring colour strength or predicting a mix.
A replacement example
For an order that explicitly names Cotman 660, keep both the range and number. A different brand’s Ultramarine withPB29 may be a relevant product to investigate, but it is not an automatically approved identical replacement. A different Cotman blue with another code also needs its own source record.
A concrete order check
A commercial colour name can remain familiar while the listed pigment field changes across a range or version. Preserve the exact maker row and date for the selected record. The journal has not compared the chemistry of every product called Ultramarine,so a matching word on another label is a reason to investigate rather than a completed equivalence finding.
Next action
Read the exact supplied label and current maker colour chart. If a retailer gives a conflicting pigment code, preserve the discrepancy and ask the maker. This journal has not produced swatches, measured spectra or verified a visual colour match from a screen image.
Sources & scope
Checked November 5, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or retailer instructions. Current received labels and independent art-material/chemical/content/commerce review remain pending.
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