Physical dimensions on chain
A reading profile: actual-size/physical-dimensions/1
The position
A token can already state the physical size of the work behind it.
ERC-6596,
the Cultural and Historical Asset Token metadata extension, was created on 28 February 2023
and carries Dimensions Unit, Dimensions (height),
Dimensions (width), Dimensions (depth) and
Is Physical Asset.
It has held the status Review since 28 November 2023.
No marketplace renders those fields. A token carrying an exact measurement of a 2 metre painting displays at the same size on screen as one carrying a postcard.
This page sets out the profile Actual Size would read.
What is out there now
Surveyed on Objkt, the largest art marketplace still trading, on 13 September 2026. Of 1,200 recent tokens, none stated a physical size. Not one carried an ERC-6596 dimension trait. Not one had a trait whose name mentioned a dimension at all.
Every attribute named Dimensions on that marketplace holds pixels.
Artists record the physical size anyway. With nowhere to put it, they write it into the trait name:
"13.5 cm by 21 cm" = "3000 x 3000 px" "41.997 x 59.401 cm" = "29.1 MB" "3635 x 2908 pixels / w 50 x h 40 cmts" = "30 Mb" "Dimensions" = "2400px x 3000px"
The measurement exists. The container does not. This profile reads all four of those shapes.
The traits
Emit ERC-6596's traits, unchanged. Nothing here is new.
{
"name": "Untitled",
"description": "Oil on linen.",
"image": "ipfs://...",
"attributes": [
{
"trait_type": "Dimensions Unit",
"value": "cm"
},
{
"trait_type": "Dimensions (height)",
"value": 116
},
{
"trait_type": "Dimensions (width)",
"value": 90.5
},
{
"trait_type": "Is Physical Asset",
"value": true
}
]
}
Dimensions Unit accepts mm, cm, m, in and ft. Height and width are
required. Depth is optional.
Measure the work. The frame is not the work.
What is also read
Any attributes entry named Height and Width, where a unit appears in the
value, in the trait name, or in a shared Unit trait.
TZIP-21 dimensions, only when its unit is a physical one. That field is
specified as the dimensions of the file, and its own example is 512x512 in px.
What is refused
A measurement in px, pt or dp. Those describe a file.
A number with no unit.
A unit that is not on the list above.
Any dimension below 0.5 cm or above 20 m. Outside that range the unit is wrong, and a renderer makes a wrong unit look authoritative.
A work whose size cannot be read still hangs, at an approximate size, and its label says so. It is updated once the true size is obtained.
What this is not
Actual Size does not mint, custody, list for sale, take payment, or hold a key.
It would read a contract the artist owns and draw the work at the size the artist recorded.
The historic collection on this site is public domain, is free, and is never minted.
Provenance
Every work states where its measurement came from: Measured by the museum, Recorded on Wikidata or Measured or provided by the artist. A work with no published size states that it hangs at a display size.