Reading acrylic colour codes
Every acrylic colour carries a number. It is not a part number and not a RAL shade, but the only thing that identifies a tint unambiguously across suppliers and years.
Reviewed on 12 September 2026
We call a colour „black, opaque (9H01)" or „light blue, transparent (5C18)". The part in brackets is the sheet manufacturer’s colour number. It denotes exactly one tint — the same number appears at the sheet merchant, in the data sheet and on the pallet label.
Colour names are no substitute. Acrylic GS alone contains „red" twice: 3H01 blocks light, 3H55 lets it through. And what is called „signal yellow" here is „traffic yellow" at the next supplier. The number stays the same.
The first position names the colour family
| Position | Family | Example from our range |
|---|---|---|
| 0 | clear | clear, transparent |
| 1 | yellow, cream | yellow, opaque (1H01) · cream, translucent (1H02) |
| 2 | orange | orange, transparent (2C04) · orange, opaque (2H02) |
| 3 | red, pink | red, opaque (3H01) · pink, translucent (3H00) |
| 5 | blue | blue, translucent (5H48) · light blue, transparent (5C18) |
| 6 | green | green, translucent (6H01) · yellow-green, translucent (6H02) |
| 7 | grey, umber | grey, opaque (7H32) · umber, transparent (7C22) |
| 8 | brown | brown, transparent (8C01) |
| 9 | black | black, opaque (9H01) |
| WH | white | white, opaque (WH01) · white, milky (WH02) |
The manufacturer publishes no key to its numbering. It can still be read off: across our whole range it works without exception. The digit 4 does not occur here.
C or H — how much light gets through
A C number is clear and see-through. You look through it as through tinted window glass, and contours behind it stay sharp. That holds for every C grade we carry, from 5C18 light blue to 8C01 brown.
An H number is pigmented throughout. How much light remains depends on the amount of pigment, and the range is wide: 5H48 blue still glows on a lamp, 9H01 black lets through practically nothing. So the letter alone does not answer the question.
That is why the plain word usually follows the colour name here: transparent, translucent or opaque. Transparent means you see through it, translucent means light passes but an image does not, opaque means nothing passes. A few grades carry their own wording instead: „white, milky (WH02)" names none of the three and is translucent all the same, at 44 % transmission.
What actually gets through
| Colour | Code | Light transmission |
|---|---|---|
| clear, transparent | — | about 92 % |
| white, milky | WH02 | 44 % |
| orange, transparent | 2C04 | 39 % |
| white, opaque | WH01 | 3 % |
| red, opaque | 3H01 | 2 % |
| black, opaque | 9H01 | practically 0 % |
Manufacturer figures from the colour overview linked below. For backlit parts this value decides, not the shade: „white, milky" passes fourteen times as much light as „white, opaque".
What the number does not tell you
It says nothing about how the sheet was made. The same number can appear on cast GS and on extruded XT — and that is the difference that matters for cutting and for thickness tolerance.
It is not a RAL shade and cannot be converted into one. If you have to match a colour specified in RAL, only a sample held side by side will settle it.
And it says nothing about the surface. Gloss or matt is a property of the sheet, not of the tint.
Special cases you will meet
White has letters instead of a digit: WH01 is the opaque white, WH02 the milky one used for backlit signs.
Short legacy numbers fall outside the scheme: „violet, translucent (886)" carries a three-digit number from an older series.
An SC after the number means the satin finish — 9H01 SC is the same black, matt on one side. The matt series also has a system of its own with S2 numbers, such as Chilli Red (S2 4T50).
And four-digit numbers without a letter, like Mineral Grey (9643) or Walnut Brown (5296), come from other colour series and do not follow this system.
Frequently asked questions
- What does 9H01 mean?
- The 9 stands for the black colour family, the H for pigmented throughout, the 01 is the serial number. In practice it is the standard black that lets through practically no light.
- Is the colour code a RAL shade?
- No. It is the sheet manufacturer’s colour number, and there is no conversion to RAL. If you have to meet a RAL specification, compare a sample.
- How do I tell whether I can see through the sheet?
- By the letter and the plain word after it: C numbers are see-through, H numbers pigmented. Whether a grade is translucent or opaque is spelled out after the colour name.
- Which colour should I use for a backlit sign?
- A translucent one. „White, milky (WH02)" passes around 44 % of the light and diffuses it evenly; „white, opaque (WH01)" at 3 % stays dark. Coloured translucent grades tint the light as well.
- What does the SC after 9H01 mean?
- The satin finish: same tint, one side matt. Colour number and light transmission stay as they are, only the surface changes.
- Why does violet have only three digits?
- Because 886 comes from an older colour series that predates today’s scheme. Such numbers still occur occasionally — they identify a tint just as unambiguously.
Read on
Sources
- Colour codes of our acrylic range, as of September 2026
- PLEXIGLAS® colour overview, thyssenkrupp Plastics
- Colour palette with light transmission, Novoglas
- PLEXIGLAS® Farbübersicht, thyssenkrupp Plastics (retrieved 12 September 2026)
- Plexiglas Farbpalette mit Lichtdurchlässigkeit, Novoglas (retrieved 12 September 2026)