Much like a microscope, the user can zoom into the photographs of overviews, details, and labels with the help of a zoom viewer and view details of the type specimens.
Two different zoom viewers are available:
(1) a universal viewer that is strictly HTML based and that runs with any web browser, and (2) a Java applet.
(1) The universal HTML viewer
is most suitable for slow computers or low bandwidth internet connections.
The initial photograph can be magnified by either clicking on the "+" sign on the menu bar or by clicking directly on the image. To zoom out of the picture, please choose the "-" sign. Enlarged images are reset by clicking on the "sheet" icon. With the help of the pan, the enlarged photograph can be moved according to the arrows.
2) The Java applet
provides a more convenient interface for zooming and sliding the photographs. In contrast to the universal viewer where with every scroll a new picture is loaded, soft scrolling ("hand" icon) and dynamic loading is provided by the Java applet. In addition, a movable “magnifying-glass” with an adjustable zoom factor is available in the applet version.
The photographs can be magnified by either clicking on the "+" button, or by pressing down the mouse button while dragging the cursor across the image. Releasing the mouse button will magnify the selected area. By pressing the "-" button the picture will be scaled down. Enlarged images are reset by clicking on the "white square" icon.
By clicking on the magnifying lens icon (rightmost button) a virtual lens (“magnifying-glass”) will be produced that can be dragged across the image. The magnifier is shut-off with the red lens button on top of the lens.
In order to use the Java applet, the appropriate Java tool (Java Runtime Environment; JRE) needs to be installed.