Several numbers can appear around a limited-edition artwork: a design number, an edition fraction, a stock-keeping unit and information on an accompanying certificate. They may look related, but they answer different questions.
For the Mexico City Graffiti Train Birch Wood Art Board, the key distinction is simple: Design 23 identifies the Mexico City design within the Chromatica City Series, while an edition number such as 01/25 identifies one individual board within the 25-piece Mexico City edition. Neither number should be confused with the product SKU, ET-WD-CS23.
Understanding those roles makes it easier to catalogue the board accurately, discuss it with another collector and avoid reading claims into the numbering that the numbers do not support.
The Four Identifiers You May Encounter
The product record brings together four different forms of identification or documentation:
| Mark or document | What it identifies | What it does not identify |
|---|---|---|
| Design 23 | The Mexico City design within the Chromatica City Series | A specific board within the edition |
| 01/25–25/25 | An individual board’s number within the 25-piece Mexico City edition | The design’s position in the City Series or a verified production date |
| ET-WD-CS23 | The product SKU used to identify the Mexico City birch wood art board as a product record | A unique serial number for one individual board |
| Certificate of Authenticity | Companion documentation supplied by Chromatica with the board | Independent third-party provenance or transport-operator endorsement |
These identifiers work at different levels. Design 23 operates at the artwork or series level. The edition fraction operates at the individual object level. The SKU operates at the product and inventory level. The certificate belongs to the board’s collector documentation.
What “Design 23” Means Within the City Series
Design 23 is the designation for the Mexico City artwork in the first Chromatica City Series, a 25-design collector platform based around graffiti, train culture and urban creativity.
It identifies the design concept. If two collectors own different numbered examples of the Mexico City birch wood edition, both own Design 23. Their individual edition numbers will differ, but the design number remains the same because the underlying Mexico City artwork is the same City Series design.
In practical terms, Design 23 answers:
- Which City Series design is this?
- Which city subject does the product record refer to?
- Where does this artwork sit within Chromatica’s design identification system?
It does not answer:
- Which individual board is this?
- Was this board produced before or after another example?
- When was the board made?
- Which edition number will a buyer receive?
Although the number is 23, it should not automatically be treated as a date, a production sequence or the twenty-third physical board manufactured. The verified meaning is narrower: it is the design identifier attached to the Mexico City entry in the City Series.
How to Read an Edition Number Such as 01/25
The Mexico City birch wood edition is limited to 25 pieces worldwide. Each board is individually numbered on the reverse within the published range 01/25 to 25/25.
An edition number is read as a fraction-like notation:
- The number before the slash identifies the individual example within the edition.
- The number after the slash states the total size of that edition.
For example, 01/25 means that the board carries individual edition number 01 in an edition limited to 25 pieces. Likewise, 17/25 means individual number 17 from the same total edition of 25. 25/25 is the final valid number in the stated range.
The leading zero in 01/25 is a formatting choice that keeps the individual numbers visually consistent: 01, 02, 03 and so on. It does not create a different category of edition, and it does not change the total. In catalogue software that removes leading zeros, “1/25” may be understood mathematically, but the best practice is to transcribe the marking exactly as it appears on the board.
Does each Mexico City board have a different number?
The product specification states that the boards are individually numbered from 01/25 through 25/25. That range distinguishes the 25 physical examples in the Mexico City birch wood edition.
However, the number alone does not tell you the manufacturing or shipping sequence. For example, a board marked 04/25 should not be described as the fourth board made or the fourth board shipped unless separate records specifically establish that fact. Edition numbering and production chronology are not automatically the same thing.
Is 01/25 more limited than 18/25?
No. Both belong to the same 25-piece edition. The denominator is identical, so each is one numbered example from the same published edition size.
Collectors may have personal preferences for low numbers, repeated digits or numbers with individual significance, but those preferences do not make one number objectively rarer within this edition. The numbering also does not establish resale value, future scarcity or investment potential.
Why Design 23 Is Not the Same as Piece 23/25
The easiest way to avoid confusion is to complete two different sentences:
- Design 23 means: “This is the Mexico City design in the City Series.”
- 23/25 means: “This is the individually numbered 23 example from the Mexico City edition of 25.”
A Mexico City board could therefore be described as Design 23, edition 06/25, Design 23, edition 19/25 or Design 23, edition 23/25, depending on the number actually marked on its reverse.
Only one possible board combines the same numeral in both systems: Design 23 with edition number 23/25. Even in that case, the two appearances of “23” retain separate meanings. One identifies the design; the other identifies the individual numbered example.
This distinction matters when cataloguing a collection. Entering only “23” creates ambiguity. A future reader may not know whether it means the City Series design, the individual edition number or part of the SKU. Use labelled fields rather than a single general number field whenever possible.
Where the Individual Number Appears on the Board
The individual edition number is located on the reverse of the board. The front carries the detailed Mexico City train artwork, permanently laser-engraved into 3 mm birch wood. To identify the individual example, read the reverse marking rather than trying to infer the number from the front image, product title or SKU.
When recording the number, preserve the full notation, including:
- the leading zero, if present;
- the slash;
- the denominator of 25;
- the stated location of the marking on the reverse.
For example, a complete catalogue entry would say “Edition number: 08/25, marked on reverse”, not simply “Number 8.” The full form retains the information that this board belongs to a 25-piece edition.
Do not assign a number based on an order confirmation, product image or another collector’s example. The reliable number for an individual board is the one physically visible on that board. Unless a specific number has been verified, refer to the published edition range rather than predicting which example a buyer will receive.
Natural variation is not an edition code
The board is made from natural birch wood. Grain, base color, surface texture and the resulting engraving tone can vary subtly from one board to another. Those visual differences may help an owner recognize a particular physical object, but they are not part of the formal edition-numbering system.
The reverse edition number remains the intended individual identifier. A darker grain pattern, lighter section or tonal difference should be described as a physical characteristic, not converted into an unofficial edition category.
What SKU ET-WD-CS23 Identifies
ET-WD-CS23 is the SKU assigned to the Mexico City Graffiti Train Birch Wood Art Board. A SKU is a stock-keeping unit: it helps distinguish a product record from other products or variants in a catalogue and inventory system.
The SKU operates differently from an edition number. Every board covered by this product record can share the SKU ET-WD-CS23, while each physical board carries a different edition number within the range 01/25–25/25.
That makes the SKU useful when you need to identify:
- the correct Chromatica product record;
- the Mexico City birch wood art board rather than another City Series product;
- the item referenced in an order or collection database.
It is not a serial number for one particular piece. If two collection records both show SKU ET-WD-CS23, that does not mean they refer to the same physical board. Their individual edition numbers are needed to make that distinction.
It is also better not to reverse-engineer unsupported claims from the letters and numbers within a SKU. Internal codes can be useful labels, but only their confirmed product-level function should be treated as fact. In this case, the verified point is that ET-WD-CS23 identifies the Mexico City product and is not the individual edition marking.
How the Certificate of Authenticity Fits the Record
Each Mexico City board is supplied with a Chromatica Certificate of Authenticity. The certificate should be treated as companion documentation for the physical artwork rather than as a replacement for inspecting and recording the board itself.
For collection management, keep the relationship clear:
- Use the product title and Design 23 to identify the artwork.
- Use the reverse marking to record the individual edition number.
- Use ET-WD-CS23 to identify the product SKU.
- Record that the Chromatica Certificate of Authenticity is present with the board.
When cataloguing the certificate, transcribe only information that is actually printed or written on the supplied document. Do not assume that it contains a particular field, date, signature or matching number without checking the certificate in hand.
The certificate documents the work as supplied by Chromatica. It should not be described as independent third-party authentication, a complete chain of prior ownership or proof of endorsement by a transport authority. If the board later changes hands, purchase records and ownership history are separate forms of documentation that the certificate does not automatically establish.
Keep board data and document data separate
A useful collection record distinguishes between information observed on the object and information taken from associated paperwork. For example:
- Observed on board: reverse edition number.
- Product specification: Design 23, 3 mm birch wood, A4 landscape at approximately 29.7 × 21 cm, permanent laser engraving and edition of 25.
- Associated document: Chromatica Certificate of Authenticity supplied.
This separation makes the record easier to audit later. It also prevents a catalogue from accidentally presenting a product-level statement as though it were a unique inscription on one board.
A Simple Catalogue Entry for the Mexico City Board
A collection catalogue does not need to be complicated, but it should give every identifier its own labelled field. The following structure records the essential information without merging unrelated numbers:
| Catalogue field | Suggested entry |
|---|---|
| Object title | Mexico City Graffiti Train Birch Wood Art Board – Limited Edition |
| Series | Chromatica City Series |
| Design identifier | Design 23 – Mexico City |
| Individual edition number | [Transcribe the number visible on the reverse]/25 |
| Edition size | 25 pieces worldwide |
| SKU | ET-WD-CS23 |
| Material | 3 mm birch wood |
| Format | A4 landscape, approximately 29.7 × 21 cm |
| Artwork method | Permanent laser engraving |
| Number location | Reverse |
| Documentation | Chromatica Certificate of Authenticity supplied |
If the board has been customized with suitable acrylic markers, add that as a separate condition or modification note. Do not alter the design identifier, SKU or edition fraction to indicate customization. Those fields identify the underlying product and numbered object; customization describes its current state.
A concise completed description might read: “Chromatica City Series, Design 23 – Mexico City. Permanent laser engraving on 3 mm birch wood, A4 landscape, approximately 29.7 × 21 cm. Individual edition number [number visible on reverse]/25. SKU ET-WD-CS23. Chromatica Certificate of Authenticity present.”
What the Numbers Do Not Establish
Numbering is useful, but its meaning should remain precise. Neither Design 23 nor an edition fraction establishes any of the following:
- a production date;
- the order in which boards were manufactured;
- the order in which boards were sold or shipped;
- greater rarity for a lower individual number;
- higher resale value or investment potential;
- artist-proof, printer-proof or prototype status;
- a specific train model, route, line or operator;
- licensing or endorsement by a Mexico City transport operator.
The artwork is an independent artistic interpretation of Mexico City train culture. The design number, edition notation and SKU are Chromatica product identifiers; they are not official transport-system fleet numbers or operator-issued references.
Quick Identifier Checklist
- Design 23 identifies the Mexico City design in the Chromatica City Series.
- 01/25–25/25 is the range of individual numbers in the 25-piece Mexico City edition.
- The number before the slash identifies the individual example; 25 after the slash is the total edition size.
- The individual edition number appears on the reverse of the board.
- Design 23 is not the same as edition 23/25.
- ET-WD-CS23 is the product SKU, not an individual serial number.
- A specific edition number should be recorded only after it has been verified on the physical board.
- The edition number does not prove production order, shipping order, value or rarity relative to another number in the same edition.
- The Chromatica Certificate of Authenticity is companion documentation supplied with the board; record only the details actually shown on it.
- The numbering does not imply licensing, endorsement or affiliation with a Mexico City transport operator.
In short, read the product from broadest to most specific: City Series is the collection, Design 23 is the Mexico City artwork, ET-WD-CS23 is the product SKU and the reverse fraction—such as 01/25—identifies the individual numbered board within the worldwide edition of 25.
