Preparing Digital Prepress Files

Imposition and trapping software and crop mark rendering on imagesetters are all based on the dimensions of your document page size. Therefore, if elements are floating on a larger than necessary page, they must be manually moved onto the correct page size before output can begin. This can a minor inconvenience on small jobs, or a major time consumer on larger jobs.

This may seem very obvious for trimming purposes, but if bleeds are not present on the film, bleeds must be added and new film run, or your piece will have to be under-trimmed. Lack of bleeds is sometimes overlooked during visual preflighting of your document on screen. Instead, try running reduced-size lasers showing crop marks and inspect those for proper bleeds.

Imposition and step-and-repeat procedures are better handled by dedicated software. Save yourself some time by leaving that step to us. We will tailor the multi-up layout to our sheet and press set-up for plate-ready film. Even business card documents should be created as individual pages. See page-size vs. trim size issue above. 

The only way to get a film separation for the spot color you want is to have it defined as a spot color in your document. PMS colors (i.e. Pantone 185 CV)  are not spot colors if they are defined as CMYK values in your document. Depending on the application, this can be a very time consuming fix if not properly planned for in the initial design stages.

A document made up of several spot PMS colors can easily be made to convert all colors to process upon output. Most applications have a provision for this, but note that it effects all of the spot colors in your document. If you want to retain any of your colors as spot separations, you must define all others as process within your document. Depending on the application, this can be a very time consuming fix if not properly planned for in the initial design stages.

For instance, if your import is colored "PMS 185 CVC" and your document additionally has "Pantone 185 CV", you will get two corresponding spot plates. This is a common pitfall due to the way different applications define color names. Identify how your apps name colors, and you can rename them accordingly to match.

Rotated bitmap images are a real RIP choker. Besides the added RIP time caused, other ill effects can occur depending on the application and picture box treatments. Instead, rotate the image in your photo editing app and import at 0°.

Several undesirable things could happen:

• Your bitmaps could lose too much resolution if photos are scaled above 100%, see Photographic Images section below.

• Your bitmap file size would be much larger than necessary if scaled below 100%, see Photographic Images section below.

• Predefined trapping amounts will become too slight or too large if vector art is scaled in page layout. For instance, a .2 pt trap on an overprinting stroke, becomes a full point trap when the artwork is enlarged by 500% in the page layout. Instead, scale the artwork in the native app while keeping line thickness retained and re-import at 100%.

For instance, if your import is colored "PMS 185 CVC" and your document additionally has "Pantone 185 CV", you will get two corresponding spot plates. This is a common pitfall due to the way different applications define color names. Identify how your apps name colors, and you can rename them accordingly to match.

There are times when we may need to edit your art elements and need access to the source file. Embedding the files in the document is convenient for storing all of the files you need to print, but the elements are not editable and only makes your document file size that much larger. As with font files, and when possible, use a menu-driven automatic routine for collecting the import files you need to supply for any one document.

There are times when we may need to edit your art elements and need access to the source file. That means supplying the CorelDraw (CDR) file as well as the placed EPS. Or it means supplying the layered Photoshop (PSD) file as well as the placed TIF. If we don't receive these source files and edits are required, we will wait for you to complete the changes before resuming production.

Without a proper postscript-compatible file to link to, elements copied and pasted into your document will not image correctly to an imagesetter. That means: limit your import files to TIFF or EPS and place them only through the proper import command for your application. Your application will use the appropriate import filter to properly interpret the image. NOTE: Your laser or ink jet printer will probably print the clipboard objects just fine, but your film would not be right. In fact, we will not RIP film from a document that has images pasted from the clipboard.

Fonts come from a variety of vendors and differ from one set to the next. So, even if we have copies of the fonts you are using (even helvetica), they may be different from the fonts in your document. Without the fonts from your system provided, type reflow may occur.

Typeface styles such as Bold, Italic and Bold-italic of a font are generated from separate files included with your font set on your system. If you do not have the font file for Helvetica Bold-Italic for instance, we cannot render that typeface. Some applications allow you to style a font from an onscreen pallet that does not take into account what font files you have or don't have. Also note that laser printers are very good at generating these phantom typefaces, but imagesetters won't. Learn what styles you have available and stick to them.

Missing font files is perhaps the biggest problem we face concerning digital files. Even with the best of intentions, it only takes one  missing font file to put your job on hold and behind schedule. Most desktop applications will indicate the fonts present in any one document through a printable report, providing a virtual checklist. Some go a step further and gather them for you into a specific folder. Use these techniques when possible to insure that we get all of the font files we need.

Transmissive media such as film transparencies or slide film offer more dynamic range of detail and color than reflective paper prints. All other factors being equal, you will get a much better quality image from film originals. 

There are a variety of ways to get photographic art into your electronic document and they are NOT created equal. How you choose the source of your artwork will greatly effect the quality and budget of your project: (click Because: header for more info)

• (PhotoMultiplier Technology - PMT) Drum Scanners are often the input choice when quality is the highest priority. They capture a wide range of color and detail, have a high optical resolution and therefore a high enlargement capability. Extra! Extra! can provide true 5000 dpi drum-based scans from your 10" x 13" (max.) original.

• (Charged-Coupled Devices - CCD) Flatbed Scanners and Digital Cameras are by nature less accurate concerning color fidelity and color range. Most CCD devices rely on software to interpolate the original data to higher required resolutions. Extra! Extra! will provide flatbed scans for your job only when the budget or quality considerations dictate.

• Stock photography on disk has become one of the most popular ways to obtain photographic images. You can get excellent quality for a reasonable cost. Beware however, that not all stock photo houses are created equal either. They too have to digitize the photography in some manner and can get varied results as well. Your best bet is to work with a traditional stock photo house (i.e. Photodisc) and avoid the "1,000 Images for $10" deals.

If the final output dpi (resolution) is too low, quality will suffer and if the dpi is too high, disk space is wasted and RIP times are increased. The latter situation is less severe but still undesirable. Low resolution however, could greatly effect the quality of your print. To make sure you have enough image resolution, remember that is should be between 1.5 to 2 times higher than the final output linescreen. For instance, if your film is output at 133 linescreen, the final output dpi for your images should be between 200 and 300.

The proper dpi mentioned above is a factor of the original image resolution at 100% size and the placement scaling in your layout. For instance, if you have an image at 300 dpi at 2" x 2", that's great when placed at that size. If however, you place that same image in your document at 200%, that reduces your output to just 75 dpi!

When black & white lineart is rendered as a bitmap, that resolution should be at least 600 and up to 1200 dpi. On the imagesetter RIP, the artwork is not being rasterized as halftone dots but as solid areas. Therefore, the higher the dpi, the crisper the outline of the artwork. However, continuous tone images are rasterized into halftone dots where the resolution of each dot is that of the imagesetter (2400 - 4000 dpi), but the halftone information is rendered from the image resolution.

Once an image object is rasterized at a particular size and resolution, that seals the resolution quality for that image forever. That image now has a fixed number of pixels that make up the detail of the object. For instance, a 300 dpi image at 2" x 2" (4 square inches) has 1,200 pixels total. That's why when you enlarge an image the resulting dpi or dots/pixels per inch goes down. You can resample or interpolate the image to add pixels, but you are relying on software to artificially render them. The result is more resolution or a larger image, but the quality of the detail is compromised. Resampling in small amounts is very effective and is better than scaling the image in your layout where no pixels are added. However, there are noticeable limits to how far you can go. Ultimately, the best way to gain resolution is to go back to the original and rescan.

Images in RGB or other color modes do not separate as process color correctly. If your application will not convert color images to CMYK, let us know and we can do it for you. 

The world wide web has introduced several various file formats recently that are great for the internet but not-so-great for postscript output. For commercial printing, we need to stick to the postscript-friendly TIFF (tagged image file) and EPS (encapsulated postscript) formats.