Magnification
What Is Magnification?
Magnification means enlarging what is on screen so it can be read. It ranges from the browser zoom everyone has used to dedicated software that blows a small region up to twenty times its size and follows the cursor around. At high levels the visitor is no longer looking at a page; they are looking through a moving window at a small part of one.
How It Changes the Way a Page Is Used
At four hundred percent zoom, a visitor may see one column of a three-column layout and nothing else. Relationships that are obvious at normal size disappear: a label sitting to the left of a field, an error message at the top of a form, a total at the bottom of a table. Anything positioned far from what it refers to becomes effectively invisible, because the two are never on screen together.
Zoom, Reflow and Magnifier Software
Browser zoom scales everything and, on a well-built page, triggers reflow so content stacks into a single readable column. Magnifier software enlarges pixels without reflowing, so horizontal scrolling comes back. Operating system text scaling sits between the two. A page that only survives one of these is not really accessible to low-vision users, because people mix all three depending on the task.
How It Affects Real Users
Someone with macular degeneration books a flight at three hundred percent zoom. The seat map is a fixed-width image, so it never reflows; the price updates in a sidebar now scrolled off to the right; the continue button sits below content that requires horizontal scrolling to reach. Each of those is small on its own. Together they are the reason the booking gets abandoned and made by phone instead.
Where Magnification Shows Up in an Accessibility Review
Reviewers test at high zoom levels and watch for content that is cut off, requires two-directional scrolling, or loses meaning when related elements are separated. Fixed-width containers, sticky headers that swallow the viewport, data tables and complex forms produce most of the findings. It is a manual check by nature, since a tool cannot tell whether something still makes sense once the surrounding context is off screen.