RGB vs. CMYK: What Do They Mean and What is The Difference?

RGB and CMYK are significant colour models used for digital images, colour reproduction, and printing. 

In this article, we’ll explain what RGB and CMYK mean and the differences between them. Understanding their differences and applications is essential, whether you're a graphic designer, photographer, or working in the printing industry.

• RGB vs. CMYK: What Are the Differences?
• RGB Meaning
• What is RGB Used For?
• CMYK Meaning
• What is CMYK Used For?
• RGB and CMYK Values for Printing Different Shades of Black
• What File Types Are Most Suitable for RGB and CMYK?
• How to Match RGB Colour to CMYK?

RGB vs. CMYK: What Are the Differences?

The RGB colour mode is used in digital displays and is meant for digital designs like social media images, and online infographics. 

On the other hand, the CMYK colour mode is used in printers for printing hardcopy materials like business cards, posters, and restaurant menus.

CMYK produces colours with inks or pigments while RGB produces colours with different intensities of light. Colour variation in CMYK and RGB is achieved via the mixing of primary colours.

[Note: When converting colours between RGB and CMYK, some colour shifting will occur due to the different ways in which colours are created for the two colour spaces. Therefore, the colour space and the intended output (digital display or print) must be considered when working with colours in digital imaging and design.]

RGB Meaning

RGB (Red, Green, Blue) is an additive colour model used in digital displays like computer monitors, TVs, and electronic screens.

It represents colours by combining three primary colours: Red, Green, and Blue. The red, green, and blue bulbs within every pixel shine at different intensities to display different colours on LED screens. These RGB bulbs are an attempt to mimic the red, green, and blue cones or receptors found in human eyes.

The intensity of light shining from the red, green, and blue bulbs varies between 0 and 255, meaning that there are 256 levels of red, green and blue colours for colour combinations. This results in more than 16 million possible colours.

For example, when all three colours are mixed at full intensity, they create white light. 

On the other hand, when all colours are absent, it results in black colours (no light shining, RGB:0, 0, 0). 

Red Colour (255, 0, 0) + Green Colour (0, 255, 0)+ Blue Colour (0, 0, 255) = White Colour (RGB: 255, 255, 255)

What is RGB Used For?

RGB is used to represent colours in digital displays such as computer monitors, television screens, digital cameras, and mobile devices.

Application Examples:

Web Design: RGB is the preferred colour model for designing websites, web graphics, and online content since it is the standard colour representation for digital platforms.

Digital Photography: Cameras and image editing software use RGB to capture, store, and manipulate photographs, ensuring accurate and vibrant colour reproduction.

Digital Art and Graphics: Artists and graphic designers use RGB to create digital artwork, illustrations, and logos for online platforms and digital media.

CMYK Meaning

Ink Cartridges in a Printer. By DragonLord - Own work, CC BY-SA 3.0, Wikimedia Commons

CMYK (Cyan, Magenta, Yellow, Key/Black) is a subtractive colour model used in printers for colour printing processes such as colour publications and commercial printing. 

Unlike RGB, which starts with black and adds light, CMYK starts with white and subtracts colour. In the CMYK model, colours are created by subtracting different amounts of cyan, magenta, yellow, and black ink from a white background. By combining these four ink colours, a full spectrum of colours can be achieved.

For instance, when all colours are mixed at full intensity, they absorb all light, resulting in a black colour. This is known as the "key" or "K" colour.

Red Colour + Green Colour + Blue Colour = Black Colour 

However, even if cyan, magenta, and yellow were to be mixed together, the colour produced would not be dark or opaque enough to produce true blacks. Hence, printers usually have another black ink cartridge to create true black colours. 

What is CMYK Used For?

CMYK is the standard colour model for full-colour printing. When designing materials on screen, it is crucial to work in the CMYK colour space to ensure accurate colour representation on the final printed product.

Application Examples:

Print Media: Print various materials, including brochures, flyers, business cards, magazines, posters, and newspapers.

Packaging Design: Graphic designers use CMYK when creating packaging designs for products, ensuring that the colours on the packaging align with the brand's visual identity.

Advertising Materials: CMYK is widely used in creating marketing materials such as banners, billboards, and promotional materials for print campaigns.

RGB and CMYK Values for Printing Different Shades of Black

[Note: There are many variations of black, and the RGB and CMYK values may vary depending on the specific colour space and printing process used. The values in the table above are just examples of different black shades.]

Why are CMYK values in percentages and RGB values not?

CMYK values are represented in percentages because they deal with physical ink quantities and their proportions in the printing process, while RGB values are not represented in percentages as they describe light intensities in electronic displays that are measured from 0-255.

For more details on the different shades of black and other colours, check out coloursexplained.com.

What File Types Are Most Suitable for RGB and CMYK?

[Note: JPEG, PNG, and GIF are primarily used for web graphics and digital media.

EPS, PDF, and SVG can support both RGB and CMYK images. These formats are commonly used for professional printing, vector graphics, and print-ready documents.

TIFF supports both RGB and CMYK images. It is widely used in professional printing and maintains high-quality images with lossless compression.]

How to Match RGB Colour to CMYK?

How to Change to CMYK in Illustrator:

How to Change to CMYK in Photoshop:

How to Change to CMYK in Affinity Designer:

In conclusion, understanding the differences between RGB and CMYK is vital for anyone involved in digital design, photography, or the printing industry. 

RGB is suitable for digital displays, while CMYK is essential for printing. When working on design projects, be mindful of the colour model you are using and the intended output to ensure the best possible representation of your artwork or images.

For more details on what is colour space and colour gamut, check out our article: Colour Gamut vs Colour Space: What Do They Mean and What’s The Difference?

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