Every term, plainly.

Words attached to an image that show when the image does not load and are read aloud by screen readers. A banner's alt text should say what the banner says.

See also Image blocking

A signature with motion in it, usually an animated GIF of a photo, logo or banner. Done well, the motion happens once and rests on a finished frame, so clients that do not animate still show a complete signature.

See also Animated GIF, Frame one, Resting frameGIF email signatures

An image format that stores several frames and plays them in a loop. It is the one animated format nearly every mail client supports. Its transparency is one bit: a pixel is either fully visible or not.

See also Frame one, Transparent PNG

The mail app on Mac, iPhone and iPad. It plays animated GIFs and, with Mail Privacy Protection on, fetches the images in every message in advance, whether or not the person reads it.

See also Mail Privacy Protection, Email client

How many times a banner image was fetched. It is a rough measure of views, not of people: some clients fetch every image in advance and some keep copies.

See also Image proxy, Click-through rate (CTR)

The set of colours a brand uses. In a signature it covers the name, labels, text, background and icons, ideally in a light and a dark version.

See also Dark mode, Web-safe fontsBrand styling

The one thing you ask a reader to do, such as "Book a call" or "Read the report", usually as a button or banner with a link.

See also Email signature banner, Click-through rate (CTR)

Which campaign wins when two are scheduled for the same day. In Animated Signature: high, medium or low, then the later start.

See also Signature campaign

Serving part of a signature from a server at the moment an email is opened, rather than baking it into the signature. It lets a banner change without anyone pasting their signature again.

See also Signature campaign

Counting clicks on a link, usually by sending it through a redirect first. The reader chooses to click, so it records an action rather than watching them.

See also Open tracking, Click-through rate (CTR)Analytics

Clicks divided by the number of times something was shown, as a percentage. For a signature banner, "shown" is approximated by banner loads.

See also Banner loads, Click tracking

A display setting that draws mail on a dark background. Clients handle it differently: some invert colours, some leave them, so a dark logo on a transparent background can disappear.

See also Transparent PNG, Brand palette

The program used to read and write email, such as Gmail, Outlook or Apple Mail. Each draws HTML differently, which is why a signature has to be tested in several.

See also Outlook, Gmail, Apple Mail

The block at the end of an email that says who sent it: usually a name, role, company and contact details, often with a photo, logo and links. It is added automatically by the mail client to every message you write.

See also HTML email signature, Plain-text signatureWhat makes one professional

A wide image or block under a signature that promotes one thing: an event, an offer, a launch or a booking link.

See also Call to action (CTA), Signature campaignBanners

The first frame of an animated GIF, and the only one some clients show (older Outlook for Windows, or any Outlook with animation effects off). A GIF that starts blank shows nothing there, so it should start on its finished picture.

See also Resting frame, OutlookAnimated GIFs in Outlook

Google's mail service. It plays animated GIFs, loads images through its own image proxy, and keeps copies of images it has already fetched.

See also Image proxy, Email clientGmail install guide

A signature built from HTML, so it can carry layout, colour, images and links. To display the same in every client it is built from nested tables with inline styles, because most mail clients ignore modern layout and strip style blocks.

See also Email signature, Inline styles, Plain-text signature

When a mail client does not load images until the reader allows it. A signature built as one big image becomes an empty box; one built as text with small images still reads.

See also Alt text, HTML email signature

A server a mail provider uses to fetch images on the reader's behalf. It hides the reader's location from the sender and often caches the image, which is why counts of image loads are approximate.

See also Banner loads, Gmail

Styling written on each element (style="…") rather than in a stylesheet. In email it is the only styling every client honours, which is why signatures look old-fashioned in code.

See also HTML email signature

An Apple Mail setting that loads remote images privately and in advance. It makes open tracking unreliable, because images load whether or not the email is read.

See also Open tracking, Apple Mail

The signature set in a phone mail app. Most phone apps store plain text only, so a formatted signature is usually set on the desktop or web version and carried by mail sent from there; Apple Mail on the iPhone is the main exception.

See also Plain-text signature, Email client

Recording when an email is opened, using a hidden image (a tracking pixel) that reports back when loaded. It is unreliable with image proxies and Mail Privacy Protection, and Animated Signature does not do it.

See also Tracking pixel, Click trackingWhy we never track opens

Microsoft's mail client, in several versions: new Outlook and Outlook on the web, classic Outlook for Windows, Outlook for Mac and the phone apps. Classic Outlook draws email with Word's engine, and older versions show only the first frame of an animated GIF.

See also Frame one, Email clientOutlook signatures, version by version

A signature with no formatting: just lines of text. It is what most phone mail apps store, and what shows when a message is sent as plain text.

See also HTML email signature, Mobile signature

The photo that represents you in a signature or on a platform. A small, evenly lit head and shoulders crop reads best at signature size.

See also Animated GIF, Retina (2x) imageProfile pictures

Email that adapts its layout to the screen. Signatures rarely can, because many clients ignore the media queries it needs, so a narrow fixed width is the safer choice.

See also Signature width

The frame an animation settles on: the finished photo or banner. Every animation Animated Signature makes uses it as frame one.

See also Frame one, Static fallback

An image saved at twice the size it is displayed, so high-density phone and laptop screens show it sharply rather than blurred.

See also Animated GIF

A banner scheduled to run under a set of emails for a period, then replaced by the next. In Animated Signature the banner is chosen when an email is opened, so a scheduled change reaches signatures already installed.

See also Central delivery, Campaign priorityCampaigns

The line "-- " (two hyphens and a space) that has marked the start of a signature in plain-text email for decades. Some clients use it to fold or strip signatures in replies.

See also Plain-text signature

How wide a signature is drawn. Around 320 pixels fits the narrowest phone still in use; wider signatures scroll sideways or, in Apple Mail on the iPhone, shrink the whole email to fit.

See also Mobile signature, Responsive emailEmail signature design

A still image of an animation, used where motion is not wanted or not supported, such as a preview of what Outlook will show.

See also Resting frame

A tiny, usually invisible image whose load tells the sender an email was opened. It is a common spam signal and raises privacy questions.

See also Open tracking

A PNG with an alpha channel, so parts of it are see-through with smooth edges. Best for logos, which then sit on any background.

See also Dark mode, Animated GIF

Tags added to a link (utm_source, utm_campaign and so on) so web analytics can tell where a visit came from. Useful on banner links, and harmless to readers.

See also Click tracking

Fonts installed on nearly every device, such as Arial, Georgia and Verdana. Mail clients do not load web fonts from a signature, so these are what arrive as designed.

See also Brand palette