Digital File Preparation
Getting Your Files Ready For Prepress
Digital File Preparation Guide: Getting Your Digital Ducks in a Row
By: Scot Hester
The following guide will help in preparing your digital files. It contains additional information and explanations of common terms to help you communicate better with your printer.
Create documents in Page Layout Programs such as InDesign, Quark or PageMaker
- Create your document in the exact size of the final trimmed piece. For example, if you are creating a lettersize multiple-page document with facing pages, your page size would be 8.5×11, not 11×17.
- Use the master page to place common items such as page numbers in the same location on multiple pages.
- Create multiple-page documents in reader’s spreads.
- Extend images that bleed off the document page by an 1/8″ (standard).
- Delete unused colors in the color palette from EPS and page layout files.
- Images that cross-over facing pages should be divided into two separate picture boxes and aligned on their respective pages.
- Scale bitmap images no more than 10% up or down from their original size. A drastic enlargement will cause loss of detail and a drastic reduction may extend imaging time and delay your job.
- Link images in your Illustrator and FreeHand files. Do not embed them.
Tip: Remember to include any special Quark Xtensions you may have used to create your document.
Tip: Creating files in drawing programs such as Illustrator, FreeHand or Corel Draw can sometimes incur additional charges by printers.
- Save all PhotoShop files in the CMYK color mode, which includes any nested or embedded files.
- Submit PhotoShop files only in the TIFF or EPS formats (DCS is an EPS).
- Delete any unused alpha channels or clipping paths in flattened PhotoShop files.
- Delete unused colors in the color palette from Illustrator, FreeHand.
- Turn off JPEG, LZW, or ZIP compression in your PhotoShop files.
There are two types of images: Vector and Bitmap. Vector images consist of lines and curves you create in programs like Illustrator or Freehand.They are called vectors because they can be described in mathematical terms such as size, length and position.Vector graphics are device-independent, meaning they can be scaled up or down with no loss in detail.
Bitmap images are created in painting programs such as PhotoShop. Bitmaps (also called, raster images) are created on a grid with small squares called, pixels. Each pixel has a location and color value assigned to it.These images are device-dependent, meaning they have a fixed number of pixels for a given area. Images that look jagged or bitmapped do not have a sufficient amount of pixel information or resolution. A high resolution image will have more pixels per grid, which allows for greater detail and color transitions.
Tip: A formula for determining resolution (dpi) is: 1.5 x the line screen = resolution. Many still use the old formula of 2x the line screen, but there is no visible loss of detail at this lower dpi and it saves valuable disk space.
Bitmap (in Bitmap mode) Typically black & white images (no grays) used for text or logos.These should be saved at 600 dpi, as a TIFF and scaled to 100% of the intended size.The background can be set to none. Use your page layout program to colorize the image.
Bitmap (in Grayscale or CMYK mode) These are black & white or color images.They should be saved at 225 dpi, as a TIFF or EPS and scaled to 100% of the intended size. Printers prefer TIFFs if there are no clipping paths, because EPSs tend to have a slightly larger file size.The background should be set to white or a color in QuarkXpress.
Tip: If you are creating an image with a clipping path it must be saved as an EPS and the tolerance should be set between 2 and 4, with 2 being a tighter setting for irregular shapes.
Bitmap (in duotone mode) These images can be monotones, duotones, tritones or quadtones and must be saved as an EPS.
Tip: Use channel 1 for the darkest color and if you are using black make sure it says Black in the window, not Process Black (your page layout program will see it as a different color). Set the screen angles in your page layout program not in PhotoShop. Scott Lithographing can select them for you upon request.
Vector Can be saved at any size and scaled up or down in your page layout program (we suggest 100% for a better preview) and they can only be saved as an EPS.
Tip: Prevent gradient banding: Set the output resolution to 2540.
You may color correct in RGB or LAB, but save images that will be imported into you page layout program in CMYK mode. Importing in RGB will prevent the image from being output properly. RGB is for images that will only be viewed on a monitor.
Tip: Remember to calibrate your monitor frequently and delete any alpha channels to reduce the file size.
Spot (PMS) colors must use the same name in all image files. For instance, if you are using PMS 185 CV in a file and PMS 185 CVU in another, your page layout program will see them as two separate colors. Please indicate if a PMS color is to be spot or built out of process colors.
Tip: Keep in mind that some spot colors do not reproduce satisfactorily when built out of process.
Tip: If you are using metallic inks it is a good idea to aqueous coat or varnish the sheet to prevent smearing.
- Be sure to include the printer and screen font for each Type 1 font.
- Check the font usage window to ensure you have included all your fonts.
- If you’ve used fonts in EPS artwork: Either convert the text to paths or include the font(s).
Basic types of fonts: PostScript, TrueType, OpenType.
Postscript comes in Type 1,2, or 3 (Type 1 is the most popular).You will have two fonts; the screen font and the printer font.The screen font is for displaying the font on your screen (the icon shows a single “A”).The printer font is used by printers and imagesetters to create the type mathematically.
TrueType contains both the screen and printer fonts in one file (the icon shows three “A”s).
OpenType fonts are gaining in popularity due to their cross-platform ability and flexibility. They are essentially a Type 1 or TrueType font in a TrueType shell, so you will have only one file per font weight or style (i.e., bold, italics, small caps, etc…).
Tip: Use current and brand name fonts whenever possible (ie.Adobe, Bitstream). Keep a compressed version of your font library and replace any fonts that cause printing problems.
Tip: Use the actual weight of the typeface, such as Helvetica Bold.Do not use menu styling.
Printers normally handle trapping, so discuss any concerns you have. If you are comfortable doing your own, you should relay that to your printer. Although, it may make you liable for any trapping errors.
As a rule, printers do not check the spelling of documents because they are not privy to the jargon, product names, or special pronouns of other industries. Spell-check and proof-read your document carefully. It’s also an excellent idea to have two other individuals proof-read the text before submittal.
Printers were primarily Mac-based, but virtually all of them now accept PC files created in Quark Xpress, Pagemaker, InDesign, Photoshop, Illustrator, Freehand, and Corel Draw EPS files. It’s a good idea to check with your printer before submitting files created with Microsoft products, such as MS Word or Publisher.
I strongly suggest using the Collect for Output option when using QuarkXpress. Collect all the elements of your job (images, fonts and final files) and place them into one of three folders: Finals, Support, and Fonts.Do not send files that are not pertinent to the job. Please be aware that Quark will list the fonts on the collect for output report, but it will not collect them for you.
Tip: I strongly recommend using FlightCheck or PreFlight Pro prior to submitting your files.
Printers accept just about any media today, and many have ftp sites that can save you travel time. Once you have the user name and password. You can upload files via our FTP. Here’s the link: http://www.printbasics.com/DropBox
Be sure you have a back-up copy of your project. I suggest a regular archiving procedure to ensure you have your work in the future.
FINAL CHECK LIST:
- All electronic files, support images and fonts on disk.
- All photos, transparencies, or art to be scanned.
- Any special instructions.
- A set of color proofs or lasers.
- A set each of b&w laser composites/separations.
- A mock-up (if applicable).
- A previously printed sample (if applicable).