USEFUL
STUFF.

The A Series

The A series is the most commonly used paper size standard. Each size is exactly half the one above it, so two A4 sheets make one A3, two A3 make one A2, and so on. The standard is set by ISO 216 and used across most of the world.

Size	Millimetres	Common Use
A0	841 x 1189mm	Large posters, technical drawings
A1	594 x 841mm	Posters, flip charts
A2	420 x 594mm	Posters, diagrams
A3	297 x 420mm	Newspapers, menus, portfolios
A4	210 x 297mm	Letterheads, brochures, forms
A5	148 x 210mm	Leaflets, notepads, booklets
A6	105 x 148mm	Postcards, pocket booklets
DL	99 x 210mm	Envelopes, compliment slips

The C Series

The C series is used for envelopes. A C4 envelope fits an A4 sheet unfolded. A C5 fits an A5 sheet, or an A4 folded in half. A C6 fits an A6 sheet or an A4 folded into quarters.

RGB is for screens

RGB (Red, Green, Blue) is the colour model used by screens, monitors, phones and TVs. It creates colour by adding light. The range of colours available in RGB is wider than in print.

CMYK is for print

CMYK (Cyan, Magenta, Yellow, Key/Black) is the model used for printing. Inks are layered to absorb light rather than emit it. If you are sending artwork to a printer, it must be in CMYK. Sending RGB files to print will result in colour shifts, and sometimes significant ones.

Spot colours and Pantone

Spot colours, often specified using the Pantone Matching System, are pre-mixed inks used for precise, consistent colour reproduction. If colour accuracy is critical to your brand, specifying a Pantone reference is the safest approach. Always ask if you are unsure which profile you need.

Print needs 300dpi minimum

Print requires high resolution images. The standard minimum is 300dpi at the size the image will appear. An image that looks fine on screen may be completely unusable in print. A 72dpi web image blown up to A4 will look pixelated and blurry.

Always supply the highest resolution version you have. If in doubt, send what you have and we will tell you whether it works.

Web uses 72dpi

Screen resolution is typically 72dpi, much lower than print. A high-resolution print image used on the web will be unnecessarily large and slow to load, without looking any better than a properly sized web image.

File formats at a glance

Format	Best For
PDF	Print-ready artwork, always preferred
TIFF	High resolution print images
EPS / AI	Vector logos and artwork
JPEG	Photography, web and print at high quality
PNG	Web graphics, logos with transparency
SVG	Web logos and icons, fully scalable

It’s easy to assume that if an image is sitting on a search engine, it’s free for the taking. But grabbing someone else’s work without permission isn’t just a grey area, it’s copyright theft, and the legal penalties can be severe.

The smart alternative is using professional stock libraries like Shutterstock, iStock, or Dreamstime. For a nominal licensing fee, you get access to millions of professional images that elevate your brand and keep you safely on the right side of the law.

Bottom line: Be professional. Buying the right image once is infinitely cheaper than paying the price of a copyright fine later.