What are RGB, CMYK and PMS?

To ensure our colours look the same, use the right colour model for the right application.

The Leiden University colours must look the same everywhere: on a computer screen, in a brochure and on a flag. To ensure this consistency, we have colour models: RGB, CMYK and PMS

RGB: for anything on a screen

RGB is the language of screens. In this model, colours are created by mixing Red, Green and Blue light. This is called an additive colour system: when you combine all three colours at full intensity, you get white light. Without light, you get black (a screen that is turned off).

• When to use RGB? For all on-screen material: websites, presentations, social media posts, videos, online advertisements and so on.
• How is it represented? RGB colours are often defined by RGB values (e.g., rgb(0, 32, 91)) or hexadecimal codes (e.g., #00205B), which you use in software and CMS systems.
• Please note: An RGB colour on a screen can look different when printed.

CMYK: for full-xolor printing

CMYK is the standard for full-colour printing. This system works by mixing inks in Cyan, Magenta, Yellow and Key (black) on paper. This is a subtractive system: the ink absorbs light. If you use no ink, you see the white colour of the paper.

• When to use CMYK? For printing full-colour materials like brochures, flyers, posters and dissertations containing photos.
• How is it represented? CMYK values are expressed in percentages of each ink colour (e.g., C100 M90 Y10 K50).
• Please note: CMYK has a smaller colour spectrum than RGB. Bright, vibrant screen colours can appear duller in print.

PMS (Pantone): for guaranteed colour consistency

The Pantone Matching System (PMS) is not a mix of base colours, but a standardised library of pre-mixed inks. Each colour has a unique number, allowing a printer anywhere in the world to reproduce the exact same shade. This is crucial for brand identity.

• The Leiden University house style colour is PMS 280 C.
• When to use PMS? For printed materials where colour consistency is essential, such as logos on letterheads, business cards, flags, and merchandise. It is often used for print jobs with one or two specific colours.
• How is it represented? By a unique code, such as PMS 280 C. The letter (C or U) indicates the paper type: C for coated and U for uncoated.

Which system should you choose?

Use this table as a quick guide to select the right colour system.

Application	Color System	Example
Website, presentation, social media	RGB	An atmospheric image on a webpage or a chart in PowerPoint.
Brochure, flyer, dissertation (full-colour)	CMYK	A printed folder with many photos and colorful elements.
Letterhead, business card, flag	PMS	The official university logo on printed materials to guarantee color consistency.

By choosing the right colour system, you ensure that the university's visual identity is always displayed professionally and consistently.