Here at American Reprographics Inc., we use the term "PDF Processing" to describe the overall process which we go through to set-up or pre-flight all digitally received drawing files. There are several steps involved in preparing files so that they can be archived and printed properly. Here is a brief overview of these steps and the problems that we most often encounter.
1. Ripping the file (processing or translating the file into a temporary
2. Previewing each file for errors and correcting when necessary
3. Creating TIF files to be archived
4. Putting files in correct order according to index and saving project job.
Details about each of these steps:
1. RIPPING THE FILE
The first step, after receiving any file, is to "rip" that file into a printable format. A raster image processor (RIP) is the component used in a printing system which produces a raster image. The RIP applies either smoothing or interpolation algorithms to the input raster image to generate the output raster image.
The most commonly generated drawing file in the reprographics industry today is the Portable Document Format, or PDF. However, all PDF files are not created the same. Some are scanned files and some are created from an original digital source such as AutoCad. Ripping time can vary greatly depending on the source and the method in which the PDF was created. For example, if layers haven't been flattened, then the ripping speed can be very slow. If there are font issues that pop up or if the file was created using a 3rd party free conversion tool, then this too can create problems during the rip process. Sometimes the file will fail to rip.
What happens if a file fails to rip? Here at American Repro, we have a 4-tiered approach with different software solutions so that if a file fails, it is escalated to the next tier. As long as the file is not actually corrupt, we can process up to 99.9% of all PDF files that we encounter. If the file is actually corrupt, then we will contact the client immediately to make them aware of the problem. Our competitors, on average, only use one or two software applications to rip files.
2. PREVIEWING EACH FILE
After each file is ripped, we check every single file for possible problems. Typical issues that occur are: font issues, scale issues, image orientation, mixed sized drawings within a single project, image rotation problems, blank drawings, line weight issues, and gray scale issues. Most projects consist of files that are created from different consultants, different sources, or different softwares. Therefore, almost every project will present one or more of these challenges. Once all of these problems are resolved and the files are of a uniform standard size, oriented and rotated correctly, then the files can be archived as TIF files.
3. CREATING TIF FILES
Not all TIF files are the same. The files we create are specific TIF files meant for archiving and printing. The files are black and white 1 bit CCITT Group 4 TIFs. This makes for smaller file sizes without sacrificing image quality. Acrobat Professional cannot export or create these kinds of TIF files. Once the TIF files are created, then a project job can be created which will also be archived for future printing needs. This TIF files also becomes the key building block file for any other needed application, such as PlanWell, our online planroom, CD burning, and so on.
4. PUTTING FILE IN CORRECT ORDER
Lastly, a job is created and the files are then put in the correct printing sequence according to the project's index. During this process we check for any discrepancies such as extra, missing or duplicate drawings. Whenever there is a discrepancy we will contact the client to find out how they would like it to be resolved. We will find out if we need additional files before we can start printing or if it is OK to proceed as is. Once the project is correctly set-up, the job file is also archived with the TIF files for future printing needs.