At a glance
| Word | What it can mean | Write instead |
|---|---|---|
| Brushed | Any line finish made with a brush, belt or pad. | The stainless code 2J with a grit or Ra, and the direction. |
| Satin | A fine abraded finish, a plated satin, or a sheen on a coating. | Say which: abraded (M31 or 2K), plated, or coating sheen. |
| Polished | Shiny in speech. In US stainless practice it also covers Nos. 3 and 4 with visible grit lines. | Mirror (2P), or the code and Ra. |
| Hairline | Very long fine lines. ASTM A480 does not define it; suppliers call it No.5 or No.6. | A sample agreed in advance. |
| 2B and BA | 2B is a smooth grey mill sheen. BA (2R) is bright and gives a clear image. | The EN code. |
| Burnished | Smoothed by rubbing under pressure, or a dark rubbed-back look. | Say what is done. |
| Antique, aged, oxidised | Trade words with no standard. Hardware keys disagree. | Colour, process, seal and a sample. |
| Etched | Aluminium: overall matte. Copper alloy: a pattern. | The metal and the result wanted. |
| Gunmetal | A casting bronze, or a dark grey colour name. | 'Dark grey' plus the finish code. |
The nine words that most often cause trouble.
Three ways a surface is made
NAAMM and NOMMA's Metal Finishes Manual sorts architectural finishes into three types. Mechanical finishes change the surface by physical means: rolling, grinding, brushing, polishing, blasting. Chemical finishes use chemistry, with or without a physical effect. Coatings add a film, either converted from the metal itself or applied. The mix differs by metal: stainless steel is mostly mechanical finishes, carbon steel is mostly coatings, and copper alloys use both mechanical and chemical finishes. Only the as-fabricated, or mill, finishes are supplied by the metal's producer. Every other finish is a process finish applied by a fabricator or finisher, so the result depends on the skill of the finisher as well as the metal.
The manual also warns that many things called finishes are really steps in a process, such as cleaning, degreasing and dipping, and that perfect uniformity of colour and texture is unrealistic except with opaque coatings, especially when two finishers or two stocks of metal are involved. That is why the last section of this page ends with a sample.
For stainless sheet, the EN 10088-2 designations give a first digit for hot rolled (1) or cold rolled (2) and a letter for the finish, as in 2J. Euro Inox's guide (2005) uses the designations of the 2005 edition of the standard, which BSI shows as withdrawn on 31 October 2014. The current edition is BS EN 10088-2:2024 (as recorded on our stainless finish codes sheet); we have not read it, so check each code against it.
A to B
Source keys in square brackets. NAAMM: NAAMM/NOMMA AMP 500-06, Metal Finishes Manual (2006), with its chapter. EI1: Euro Inox, Guide to Stainless Steel Finishes (2005). BSSA: the BSSA mechanical surface treatments page. Sheet: another sheet in this library, which lists its own sources. Trade: trade usage, with no standard found.
| Term | What it means | Code or also called | Watch out |
|---|---|---|---|
| Abrasive blasted (sand, shot, grit) | A surface struck by a stream of hard particles: non-directional and matt. The medium sets the look: glass beads, fine sand, stainless shot and ground quartz give different results. [NAAMM ch.3; EI1] | Copper alloys: M42 to M47 (fine, medium, coarse matte; fine, medium, coarse shot blast). | Never iron or carbon steel shot on stainless. Thin sheet distorts: NAAMM advises against blasting copper alloy or aluminium under about 6 mm. |
| Aged, artificially aged | A trade word for a surface coloured by chemistry or heat so that it looks as if time has passed. No standard defines it. NAAMM describes copper patinas as made to duplicate, by accelerated means, the weathered effects of one to twelve years. [Trade; NAAMM ch.2] | Also: antique, patinated, oxidised, weathered. | Give the process, the colour, the seal and a signed sample. Results depend on temperature, humidity and surface condition. |
| Anodised | Aluminium only: an electrochemical process that thickens the natural oxide, so the film is part of the metal's surface. [NAAMM ch.1; Sheet: plating and coating thickness] | NAAMM anodic series A10 to A40 (general, protective and decorative, architectural class II, architectural class I). | Not a finish for brass or steel. Sheet and extrusion will not match without control: see the sample approval sheet. |
| Antique (brass, bronze) | A trade word: a dark chemical colour with the high points rubbed back to bright metal, usually sealed. NAAMM describes statuary finishes being highlighted by cutting back the conversion coating with an abrasive. [Trade; NAAMM ch.2] | Hardware keys: AB, ABR, OBZ, DBZ and others. | In one UK hardware finish key, antique and oil-rubbed brass codes are described as electro-brass plated, patinated and lacquer sealed, not solid metal. Ask what the base is. |
| As fabricated (mill finish) | The surface the metal has when it leaves the rolling mill, extrusion press or mould, before any further finishing. Variants: unspecified, specular (cold rolled on polished rolls) and matte. [NAAMM ch.1, ch.2] | NAAMM M10 series. For stainless sheet see 1D, 2D, 2B and BA below. | Forming, sawing and drilling can mar it, so a visible part usually needs a finishing step specified. |
| BA (bright annealed), 2R | A cold-rolled stainless finish annealed in a protective atmosphere so it stays bright: smooth, reflective, and it reflects clear images (Euro Inox: 2R). A mill finish, not a polish. [EI1; NAAMM ch.3] | EN 10088-2 2R; US BA or 2BA. | NAAMM: the mirror-like look can vary from hazy to clear, and it is less uniform than polished stainless. |
| Bead-blasted | Blasted with beads, usually glass, to give a uniform, non-directional, low-reflective surface. [EI1; BSSA] | No designation in the 2005 EN 10088-2 table in Euro Inox: the medium and bead size are the specification. | Say the medium and bead size. Iron or carbon steel shot must not be used on stainless, and sand is not generally recommended. |
| Blackened | Steel darkened by a chemical conversion, then sealed with wax, oil or a clear coat. A surface conversion, not a thick layer. [Sheet: blackened, burnished and raw steel] | Also: black oxide (a different, industrial process). | Variable by design: specify a range on a sample, not a single colour. |
| Brushed | A directional line finish made with a brush, belt or pad. It is a family, not a grade. On stainless the EN 10088-2 code is 2J (brushed or dull polished); on copper alloys NAAMM M35 is made with a rotary wire wheel. [EI1; NAAMM ch.2] | 2J; M35; sometimes called satin or No.4. | BSSA and Euro Inox say brushed and satin polished must not be used alone: give the grit or Ra, the direction and a sample. |
| Buffed | A final smoothing with soft mops and compounds after grinding and polishing, which gives lustre while removing little metal. [NAAMM ch.1, ch.2] | NAAMM M21 smooth specular; M22 specular. | Mirror finishes magnify waviness (oil canning) and scratches: NAAMM keeps them to small areas. |
| Burnished | Two meanings. In metal finishing, smoothing a surface by rubbing under pressure rather than by removing material (Euro Inox glossary). Designers also use it for a dark, rubbed-back look. [Sheet: blackened, burnished and raw steel; Trade] | Burnished bronze, burnished steel. | Say what is done to the surface and approve a sample. |
C to M
| Term | What it means | Code or also called | Watch out |
|---|---|---|---|
| Clear coat, lacquer | A clear organic film that slows tarnishing on brass and bronze by acting as a thin barrier layer on the metal. [NAAMM ch.2; Sheet: lacquered vs unlacquered brass] | NAAMM O series (air dry O6x, thermoset O7x). | The conservation guidance we use says lacquer always alters the look, is hard to apply thin and even, and is hard to remove. It wears where hands land. |
| Coined, embossed, patterned | Pattern rolled into sheet. Coining uses one patterned roll and leaves a one-sided pattern; embossing uses two and prints both faces. It stiffens the sheet and improves visual flatness. [NAAMM ch.3; EI1] | Stainless 2M (one side patterned), 2W (pattern through both sides). | Mill-rolled patterns cannot be matched in the fabricator's shop. |
| Conversion coating | A chemical treatment that converts the surface film. On copper alloys it makes patinas and statuary colours; on aluminium it is mostly a pretreatment. [NAAMM ch.1, ch.2] | Copper alloys: C50 to C56. | Colour depends on temperature, humidity, surface condition and method, so uniformity over large areas is hard. |
| Electroplated (chrome, nickel, brass plate) | A thin metal layer deposited with an electric current. BHMA hardware codes include 625 (bright chromium plated over nickel) and 626 (satin chromium plated over nickel). [NAAMM ch.2, Table 2-1; Sheet: plating and coating thickness] | BHMA 625, 626 (US26, US26D). | Thin: it can wear through at touch points to the metal beneath. 'Satin chrome' names a plated finish: ask what the layer sits on. |
| Electropolished | An electrochemical process that smooths stainless by removing the peaks of the surface, which makes it easier to clean. The result may not reach the reflectivity of mechanical polishing. [EI1; Sheet: pickling, passivation and electropolishing] | Not the same as buffing. | Specify the result and the test, not just the word. |
| Etched | On aluminium, an overall matte surface made by chemical etching. On copper alloys the word usually means selective etching to produce a design. [NAAMM ch.1, ch.2] | NAAMM C20 series (aluminium). | Same word, two meanings: say which metal and what is wanted. |
| Ground | A uniform, one-direction surface with low reflectivity. Euro Inox says its coarseness restricts it to interior use. [EI1] | EN 10088-2 1G or 2G. | The grit or the roughness can be specified: do so. |
| Gunmetal | A trap. In copper-alloy practice gunmetal is a casting bronze of about 10 per cent tin and 2 per cent zinc, according to one stockholder's glossary, yet it is also used as a dark grey colour name. [Sheet: brass alloys explained; Trade] | Dark grey, bronze-grey. | Write 'dark grey, finish [code]' for a colour, and name the alloy for the metal. |
| Hairline | A finish of very long, seemingly endless polishing lines, more reflective than No.4. ASTM A480 does not define it. [NAAMM ch.3] | Long-grain, fine-line; some suppliers call it No.5 or No.6. | NAAMM advises a visual standard agreed in advance by all parties. |
| Hand-rubbed | A directional satin made by hand with abrasive pads or wool, often used to even out and blend satin finishes made by other means. [NAAMM ch.2] | NAAMM M34. | Expensive: used where machines cannot reach or to blend. |
| Living finish | Metal left unsealed so that it keeps changing with touch, moisture and time. No standard defines it. [Sheet: patination; Trade] | Also: raw, natural, unlacquered. | Tell the client in writing. See the cleaning and maintenance sheet. |
| Matte dipped, bright dipped | Chemical dips used as steps within a process. NAAMM says neither should be specified as a final finish on copper alloys. [NAAMM ch.2] | No code in the sources read. | Uniformity is hard to control. |
| Mill finishes 1D, 2D, 2B | Stainless sheet as supplied. 1D: hot rolled, annealed and descaled, slightly coarse, very low reflectivity. 2D: cold rolled, dull, low reflectivity. 2B: as 2D with a final light pass on polished rolls, a smooth grey sheen and the most widely used. [EI1] | EN 10088-2 1D, 2D, 2B. | NAAMM: 2B can vary significantly from supplier to supplier and coil to coil. |
| Mirror polish | The brightest mechanical finish: polishing then buffing, giving a clear, distinct image. EN 10088-2 2P; ASTM No.8. [EI1; NAAMM ch.3] | 2P; No.8. 'Super No.8' and 'No.9' are supplier terms that ASTM does not define. | Magnifies flatness faults and shows every scratch and fingerprint. |
N to W
| Term | What it means | Code or also called | Watch out |
|---|---|---|---|
| No.3, No.4, No.6, No.7 (US numbers) | ASTM A480 finishes for flat stainless. No.4: general-purpose polished, linear texture, Ra generally up to 25 microinches (about 0.64 micrometre). No.3: coarser, Ra up to 40 microinches (about 1.0 micrometre). No.6: dull satin, Tampico brushed. No.7: high lustre, grit lines still visible. [NAAMM ch.3] | No.4 is close to EN 2J (see the stainless finish codes sheet). | NAAMM: no common stainless specification requires a finish to meet a roughness, and ranges overlap. Specify Ra. |
| Oil-rubbed bronze | BHMA 613, 'dark oxidized satin bronze, oil rubbed' (US10B), listed by NAAMM among the common brass and bronze hardware finishes. [NAAMM ch.2, Table 2-1] | BHMA 613; US10B. | Oiled finishes need re-oiling: NAAMM gives weekly oiling for the first month, then by traffic. |
| Oxidised | NAAMM: oxidized finishes represent the natural aging of metals and change with time, and artificial ones do not necessarily match natural ageing. Also used for chemically darkened metal. [NAAMM ch.2] | Statuary (brown); BHMA 623 and 624. | Not a fixed colour: approve a sample and expect change. |
| Passivated | Treatment of stainless with an oxidising acid, such as nitric or citric, that helps the protective film form. No metal is removed, so it does not remove heat tint. [Sheet: pickling, passivation and electropolishing] | No code in the sources read. | Not the same as pickling. |
| Patina, patinated | A surface layer on copper alloys: green verdigris or brown statuary, formed naturally or by conversion treatment. NAAMM series C50 to C53 are patinas, C54 to C56 statuary. [NAAMM ch.2; Sheet: patination] | Verdigris, green patina. | A true patina is not fully uniform. NAAMM says patinas suit non-traffic areas, and a clear coat added for wear tends to alter the colour. |
| Pickled | Acid treatment that removes a thin layer of metal, including weld heat tint and the chromium-poor layer beneath. [Sheet: pickling, passivation and electropolishing] | No code in the sources read. | Not the same as passivation. Acid pastes are hazardous: see the sheet. |
| Polished | A surface smoothed by successive grinding and polishing abrasives, often followed by buffing. In speech it means shiny, but in US stainless practice Nos. 3 and 4 are 'polished' finishes with visible grit lines. [NAAMM ch.2, ch.3] | Mirror, specular, bright polished (2P). | Never specify 'polished' alone: give the code, or the grit and Ra. |
| Powder coated | A polymer powder fused to the metal: a coating, not a metal finish. [Sheet: powder coating metalwork] | RAL colour and gloss: see the RAL sheet. | The aluminium schemes do not cover steel: see the sheet. |
| PVD | Physical vapour deposition, also called sputtering: a very thin, hard, coloured ceramic coating deposited on stainless steel in a vacuum chamber. [NAAMM ch.3; Sheet: PVD coatings] | NAAMM gives gold (TiN, 'Ti-gold'), black, blue, rose gold and brass. | It follows the texture beneath, and Euro Inox says damage cannot be repaired. |
| Satin | A fine directional finish of limited reflectivity. NAAMM for copper alloys: fine satin 240 to 320 grit (M31), medium 180 to 240 (M32), coarse 120 to 180 (M33). On stainless, EN 10088-2 2K 'satin polish' adds a transverse Ra under 0.5 micrometre. [NAAMM ch.2; EI1] | M31 to M33; 2K. | Also a sheen word on lacquer and powder coat, and part of 'satin chrome', a plated finish. Say which. |
| Specular | NAAMM's word for mirror-like. A smooth specular finish is the brightest mechanical finish; plain 'specular' is a lesser polish that may leave some scratches. [NAAMM ch.1, ch.2] | M21 smooth specular; M22 specular. | Rare outside NAAMM-style specifications: write mirror polish and a code. |
| Statuary (bronze) | A brown oxide or sulphide conversion on copper alloys, often highlighted by cutting back the surface with an abrasive. BHMA 623 is light and 624 dark oxidised statuary bronze, clear coated. [NAAMM ch.2] | C54 to C56; BHMA 623, 624. | NAAMM: the hardest standard finish to produce in a given shade. The highlights disappear as the metal oxidises, so protect them. |
| Swirl, engine-turned, vibration | Patterned grinds on stainless: overlapping circles (engine-turned), swirls, and a very fine non-directional pattern called vibration or 'angel hair'. Angel Hair and Suede are proprietary names. [NAAMM ch.3] | No code in the sources read. | They hide light scratches in busy areas. Match by sample. |
Writing a finish into a specification
Because the words are not fixed, a finish line on a schedule works best when it says six things in the same order every time:
- The metal and grade, for example 304 stainless or CW508L brass.
- The process: ground, brushed, bead-blasted, polished, plated, patinated.
- A code, or a grit and a roughness, where one exists: see the stainless finish codes and the ironmongery finish codes.
- The direction of the lines, set on the drawing.
- The seal or coating: lacquer, wax, plating, PVD, or none (a living finish).
- The sample that governs, signed, with its limit samples: see sample approval and batch variation.
Where a supplier's own finish name is used, attach its definition. For the care of each finish see cleaning and maintaining metal finishes, and for what each finish does at a handle or a rail see high-touch hospitality metal finishes.
Specification wording
Paste into your schedule or specification and replace anything in [square brackets] with your own figures. Wording is a starting point: your specification governs.
Mechanical finish on stainless
Finish: [304 / 316] stainless steel, EN 10088-2 designation [2J] to [edition], surface roughness Ra [0.5] micrometres maximum measured [across the lines], line direction [vertical], free of iron contamination. The words brushed, satin and hairline are not a specification on their own. Approved against control sample [reference, date] signed by [parties] and held by [each party]; the sample governs.
Antique, aged or patinated metal
[Brass / bronze] with [antique / aged / patinated] finish to approved sample [reference]: process [description supplied by the workshop], colour [description], high points [rubbed back / left as patinated], [sealed with [coating] / left unsealed as a living finish, with care as in the operation and maintenance manual]. The signed sample governs.
Finish line on a schedule
Each finish is stated in this order: base metal and grade; process; code or grit and Ra; line direction; seal or coating; sample reference. A supplier's own finish name or code is attached with its written definition.
Terms used on this page
- Surface roughness (Ra)
- The average height of the peaks and troughs of a surface, in micrometres, read with an instrument. Lower is smoother, and the reading depends on the direction it is taken in.
- Grain direction
- The direction of the lines on a brushed or ground surface. It is set at the drawing stage and marked on the metal so that panels are fixed the same way.
Standards and sources
- NAAMM/NOMMA AMP 500-06, Metal Finishes Manual (2006): chapters 1 to 3 read 5 Nov 2026; US practice.
- Euro Inox, Guide to Stainless Steel Finishes (Building Series Vol. 1, 3rd ed. 2005): read 5 Nov 2026.
- BSSA, mechanical surface treatments: codes G, J, K, P. BS EN 10088-2, ASTM A480 and BHMA A156.18 are named by the sources: texts not read, confirm the current edition.
Questions we are asked
What is the difference between satin, brushed and hairline?
All three are directional line finishes, and none is a precise grade. Satin is usually the finest of the abraded finishes (NAAMM gives 240 to 320 grit for fine satin on copper alloys). Brushed is a coarser, broader family made with a brush, belt or pad. Hairline has very long, continuous lines and is not defined by ASTM A480. Give a code, a grit or Ra, and a sample.
Is brushed the same as No.4 or 2J?
They are close but not interchangeable. On stainless, 2J is the EN 10088-2 code for a brushed or dull polished surface, and No.4 is the US general-purpose polished finish with a typical Ra up to 25 microinches. Neither is defined by the word brushed, and roughness readings overlap between finishes, so specify Ra and approve a sample.
What does antique brass mean?
It is a trade word with no standard definition. It usually means a dark chemical colour with the high points rubbed back, sealed. In one UK hardware key, antique brass codes are described as electro-brass plated, patinated and lacquer sealed, so check the base metal as well as the colour.
What does burnished mean?
In metal finishing it means smoothing by rubbing under pressure rather than by removing material. Designers often use it for a dark, rubbed-back look. Say what is done to the surface, and approve a sample.
What is the difference between 2B and BA?
2B is the common cold-rolled mill finish with a smooth grey sheen. BA, bright annealed, is annealed in a protective atmosphere so it stays bright and gives a clear reflection (EN 10088-2 2R). BA is not a polished mirror.
Do these terms mean the same at every supplier?
No. NAAMM warns that a finish from different suppliers or coils will not match exactly, and that the same name can cover visibly different finishes. Attach the supplier's definition and a signed sample to the schedule.
Download the factsheet
A two-page A4 PDF with the nine trouble words, the six swatches, the whole glossary in brief and specification wording, to keep with your project file.