Find the Differences!
What to do about the countless preprinted forms floating around a company when the address changes? What if there's a change in the executive board or the company designs a new logo? The forms usually end up in the shredder – along with a small fortune in dollars. Especially in large firms, the value of what was once an asset can quickly climb into the tens of thousands. Policies, invoices, flyers, stationery, etc. – worthless overnight. It's not unusual for insurance companies and banks to discard 100,000 pre-printed forms every year.
Quality Assurance
Anyone who deals with mailing and printing knows: even the tiniest changes in the format can impact the layout of an entire document, whether it's a new font, a new logo, or just one extra hyphen in the company or product name. Documents are often updated using design software. The problem with that is not knowing how the changes will ultimately affect the quality of the printed page. An even more important question is whether the different versions of a document, e.g. created to reflect a software update, are identical in terms of content and layout. This is no simple task, since the check has to be run at the bit level – something that conventional composition tools just don't do.
Document comparison in the production environment is nonetheless essential to reliably ensure the necessary quality in the document creation and output. Different suppliers in the world of output management have therefore specialized in developing check programs to automatically compare documents and data streams. The software solutions list the differences found in log files, as well as displaying them graphically on the screen.
Digital Light Table
For a visual comparison, each document is converted into a pixel image of equal resolution and the resulting raster images compared, as if on a light table, where the two documents are overlaid to reveal the differences between them. The software shows the places where the two versions deviate. Users are thus able to make the necessary changes exactly where needed.
The principle: the software reads in two files, e.g. in AFP, PDF or PostScript, compares the original to the modified one and displays the differences found in just seconds. Comparisons at the pixel level identify the changes and their location. Comparisons at the structural level evaluate character sequences of the text, font attributes and other properties that affect the output.
The benefit is obvious. Production problems due to unintentional changes to the mailing are avoided. Reprints always mean reworking costs and damage the credibility of the print center with its customers.
What Really Changed?
The following illustrates just how hot this topic has become. A well-known direct mail provider generates 1,200 different documents a month, usually relatively simple, double-sided, personalized letters and correspondence. In the coming years, the company is expecting up to 5,000 different versions per month. Yet they are already struggling to reliably handle the current number. And demand for personalized documents is growing. Hardly anyone in this situation would be in a position to manually check differing versions for the needed matches and permissible deviations (including date, address field). Until recently the mailing provider used a Web-based online program for employees to check and keep track of the different versions, what happened to them and what was produced. But comparing an old and a new version was anything but simple. They had to print out the original document and then hold it up to the screen to compare it to the new – a rather tedious affair just to find out what had changed. Modern check programs like DocBridge Delta (see Background) digitize and automate these comparisons. The differences are combined in a "third" comparison document and are available to users for evaluating the print job for the customer. The advantage: the graphical display of the deviations makes for quick decision-making. Imagine a letter that looks okay, but the "overflow" from the address field is threatening to push the rest of the content downward. A graphical comparison shows the layout problems and isolates the area where the content is impacted by the changes. This makes it quick and easy to determine whether the text is the same, the breaks can be matched and whether the text is shown in the same font.
A Hyphen Can Change Everything
These tools also uncover technical differences in various software versions quickly and easily. Regression tests are critical to prevent the unwanted outcomes associated with such changes to the system software. An update, for example, may have changed the default setting for hyphenation or punctuation differences may have emerged in the address fields; one version uses periods after abbreviations, the other does not. Punctuation might not seem all that important to an outsider, but it is a quality criterion in the creation of individual documents. In the final analysis, what's important is delivering exactly what the customer asked for. Especially in companies with many different print jobs and frequent software changes, quality assurance is therefore a focal point.
DocBridge Delta is a check program that filters out and displays differences between documents quickly and reliably. The software developed by Compart is scalable, runs on all standard hardware and software platforms and is industry-independent. DocBridge Delta analyzes the objects coded in the document files right down to every detail structure. As it is able to process all the common document formats, it is able to convert entirely different input formats. On this level, DocBridge Delta compares both input documents and can display the differences object by object. Certain items can be excluded from the comparison, such as the address field, because it will change in every mailing.
For the visual comparison, each document is converted into a pixel image of equal resolution and the resulting raster images are compared. The matching pixels from both documents are displayed in grey in the generated file. However, if individual pixels appear in only one of the two documents, they are shown in green if in the reference document, with the corresponding pixels in the document to be compared in red. In this way, even the tiniest differences between objects are immediately recognizable, such as borders that differ by merely a pixel in width where font characters are edged slightly differently.
DocBridge Delta is being deployed in countless major companies, including HUK-COBURG, one of Germany's largest insurers.
