The challenge with taking Adobe Acrobat documents mobile is two fold: offering the ability to display the widest range of PDF versions and making the resulting document readable on a small screen.

At the heart of Adobe Reader LE 2.5 is a rendering and memory management engine developed by Adobe: to which Quickoffice has added the user interface. As a result, it is a little unsurprising (but no less pleasing to find) that Adobe Reader LE 2.5 managed to open every single Acrobat document thrown at it, including those in the latest PDF format (1.7). This ability also extended to very large documents, such as the 21Mb Adobe InDesign manual. Furthermore these large documents were opened as quickly as much smaller documents.

The 21 Mb Adobe InDesign manual opened on a Nokia E90.

When a document is first opened in Adobe Reader LE 2.5 it is displayed in its original layout, as it would look on a PC or when printed.

The initial view of "The 360 Degree Leader" on a Nokia E61i, one of the PDF business book summaries available through Quickmanager.

This initial view, on most devices, is effectively unreadable. So it is necessary to zoom in before the document can be read. The zoom feature - dubbed ZoomView™ - works in the same way as zoom in the Quickoffice suite. That is, once the zoom option has been selected the up and down scroll keys zoom the display in and out until the desired zoom level is found. Initially this is a little confusing, as most S60 applications offer a menu based zoom in/zoom out option, perhaps with a "select %" option, for zooming. Once the mechanism becomes familiar, however, it is much more convenient than the conventional approach; requiring significantly less clicks to find the ideal level of zoom.

ZoomView™ makes it easy to find a readable view.

While zooming, the Options menu provides more conventional zoom in/zoom out items. There are also options to select a specific zoom percentage and, when in the page layout view, zoom to the full page or page width.

Conventional zoom options are also available in ZoomView™.

In the original document layout view, efficient reading is likely to be elusive (unless the document is presented in columns of just the right width for the device's screen) as significant amounts of horizontal scrolling will be required. The exclusive Reflow mode overcomes this problem by rendering text to the width of the screen, thereby eliminating any horizontal scrolling. Unfortunately, even if you have found a comfortable zoom level in the layout view, you are likely to have to zoom again in the reflowed version to find a comfortable reading magnification.

Moving to Reflow mode may require a new zoom level to be selected.

In addition to fitting the text, Reflow mode scales images to fit the display width.

Images fitted to width on a Nokia E90 in flip closed mode.

Adobe Reader LE automatically adjusts to use the appropriate screen orientation (portrait or landscape) for the screen it is displayed on. For example, on the N93 (where the orientation depends on the screen's position) the orientation is set automatically to match the screen's position. In addition, when a document is in the page layout view it can be rotated, however reflowed text can only be viewed in the screen's native orientation.

Another challenge with reading a document on a smartphone is macro navigation, moving from page to page or section to section (as opposed to micro navigation: scrolling to see the next portion of a page). To enable macro navigation Adobe Reader LE offers options to jump to the first or last pages of the document or to any specific page by number. While the page number feature can be useful, it does make the assumption that the reader knows the specific page on which the portion of the document they want is. The most useful application of the go to page feature is in moving from a table of contents to a specific section as, unfortunately, Adobe Reader LE does not allow navigation on embedded links (such as page number links in menus).

When the position of content is unknown the bookmarks feature comes to the rescue. When opened it display the list of bookmarks contained in the document. Bookmarks are initially shown collapsed at the top level. Bookmarks with lower level items are indicated with a plus (+) sign and the details are opened from the Options menu or using the right scroll key, expanded bookmarks are then closed from the menu or using the left scroll key. Selecting a bookmark opens the document at the bookmarked page.

Bookmarks aid navigation.

While a very useful feature, many PDFs are not bookmarked. If there are no bookmarks in the document the Bookmarks option is not shown on the options menu.

If bookmarks are unavailable or specific words in the document need to be found there is a search feature. This allows a string to be located. The search provides options to match case and search above or below the current location.

Initiating a search on a Nokia E90.

Once a search has started the Options menu provides access to the "Find next" option as well as one to start a new search.

In addition to these features Adobe Reader LE 2.5 includes the ability to open password protected and encrypted files, using up to 128-bit encryption, and view document properties enabling details such as subject, keywords, date created, last modified, file size, author, and title to be seen.

Overall Adobe Reader LE 2.5 does an excellent job of rendering almost every imaginable PDF file. The rendering appears accurate, with no obvious differences between the rendering on Adobe Reader LE and the PC based Acrobat Reader. This includes documents with complex images and those that utilize shading and transparency. The fourteen fonts supplied with Adobe Reader LE also help ensure accurate rendering. The options for displaying documents allow the original format to be viewed and documents to be reformatted to a reflowed form where comfortable reading is possible.

So Adobe Reader LE 2.5 can open almost any PDF document, has useful options for viewing and reading those documents, and offers several ways to navigate and find specific parts of those documents. The final aspect of usability is therefore performance. This was generally good across a range of S60 devices. Adobe Reader LE 2.5 was tested on a Nokia N93, Nokia E61i, and Nokia E90. On all these devices text was scrolled with an almost immediate response. In addition, the size of the document made no noticeable difference to the speed at which Adobe Reader LE 2.5 could jump between pages or search text: moving between pages was as swift on the 21 Mb Adobe InDesign manual, a document of some 700 pages, as it was on documents of just a few pages.

Images, however, did cause the page rendering to slow somewhat. Scrolling through an image could be slightly erratic, as the application clearly buffers image information. So scrolling an image could initially be quite quick, but would eventually reach a point where a small delay was noticeable as the next section of image was rendered.

Generally, Adobe Reader LE 2.5 performed well and behaved as expected. Only two real issues could be noted. The first is unlikely to affect too many documents. In the Adobe InDesign manual attempting to open the bookmarks caused the document to close. For smaller documents the bookmarks worked well and provided a useful navigation option.

The second issue might be an irritation to some users. In the ZoomView™ feature the level of zoom progresses in useful increments from 100% through 125, 150, and then to 200% however the next jump is to 500%, then 1000%. This can result in having to use the "Zoom to %" option to locate an ideal zoom level. Progression at increments of 50 or 100% above 200% might be somewhat more usable.

It is also worth noting that Acrobat documents can be opened into Adobe Reader LE directly from the latest version of Quickoffice (v5.0) as well as from Adobe Reader LE itself. This is handy when there is the need to view two PDFs simultaneously, as only one document can be opened in Adobe Reader at a time.

Finally, it is worth noting that - in addition to supplying Adobe Reader LE 2.5 - Quickoffice also supplies PDF content in the form of Soundview executive book summaries. These summaries, which can be purchased through Quickmanager, offer a 4 or 5 page summaries of popular management and business books.

Soundview executive book summaries are available from Quickmanager.

Adobe Reader LE 2.5 is hard to fault. The only apparent fault was its inability to cope with bookmarks in a large PDF. When large means 20Mb, it is unlikely to be a problem for many documents accessed while mobile. It rendered every document tested. The page layout options and the Reflow mode combined with ZoomView™ means a comfortable viewing situation can be found for any document, even if the zoom scale does inflate a little too quickly once past 200%. The ability to navigate to a specific page or bookmark coupled with a powerful search makes navigating documents straightforward.

For anyone who has only the occasional need to view a PDF file while mobile the PDF viewer shipped with their S60 device might suffice. This is assuming they can cope with the frustration of finding the built in S60 will not open the latest PDF file versions, and do not mind the manic scrolling needed to read the document. For everyone else Adobe Reader LE is a must.

Adobe Reader LE is available for all S60 3rd Edition devices. It can be purchased using Quickmanager, found in most recent versions of Quickoffice, from the Quickoffice Web site, or channels such as Handango. It costs $19.95.