PDFs

The pdf format takes information from a page created by a graphics program such as Microsoft Word or Adobe InDesign and converts it to a common format that can be read on a variety of devices by the free program Adobe Reader and by the paid program Adobe Acrobat Pro. Adobe Acrobat Pro allows editing and notating the pdf.

Pdfs are good for storing text and images. When including text, the pdf conversion embeds part of the font information so that the original look of the page can be maintained without having to install those specific fonts on the device. Images are usually converted from their original format to jpeg format, with varying degrees of compression.

Graphic designers like pdfs because it is much easier to send a pdf to a printer than to send a properly packaged file with all the images and all the fonts, and if the pdf looks good when you send it, there are fewer chances of printing problems because everything is locked in place.

PDF Presets

In Adobe InDesign, there are 6 types of pdfs listed:

High Quality PDF — Intended for printing to laser and inkjet printers. High enough resolution that the images will look good when printed in this way. "This preset uses PDF 1.4, downsamples color and grayscale images to 300 ppi and monochrome images to 1200 ppi, embeds subsets of all fonts, leaves color unchanged, and does not flatten transparency (for file types capable of transparency)."¹

PDF/X — PDF-X formats are for sending to professional printers, and do not allow the embedding of interactive elements such as forms or video. Specifics:

• PDF/X-1a:2001 — Allows the use of color spaces CMYK and Spot Colors. Files are "flattened," so there are no longer items that use transparency in the document. Document needs to be checked after conversion to pdf to make sure that there are no errors caused by the flattening process. Primarily used in U.S.
  
  "PDF/X-1a requires all fonts to be embedded, the appropriate marks and bleeds to be specified, and color to appear as CMYK, spot colors, or both. Compliant files must contain information describing the printing condition for which they are prepared. PDF files created with PDF/X-1a compliance can be opened in Acrobat 4.0 and Acrobat Reader 4.0 and later. PDF/X-1a uses PDF 1.3, downsamples color and grayscale images to 300 ppi and monochrome images to 1200 ppi, embeds subsets of all fonts, creates untagged PDFs, and flattens transparency using the High Resolution setting."¹
• PDF/X-3:2003 — Allows the use of color spaces CMYK, Spot, Calibrated (managed) RGB, and CIELAB colors, with ICC Profile. Primarily used in Europe and Japan.
• PDF/X-4:2008 — Allows the use of color-managed, CMYK, gray, RGB or spot color data. Maintains PDF transparency and optional content. Images are downsampled and compressed and fonts are embedded in the same manner as with the PDF/X-1a and PDF/X-3 settings. Because the files are not flattened, proofs from the printer must be more carefully proofed to make sure that uses of transparency and special effects are properly rendered by the printer's conversion process.

Press Quality — For sending to professional printers. "Creates PDF files for high-quality print production (for example, for digital printing or for separations to an imagesetter or platesetter), but does not create files that are PDF/X-compliant. In this case, the quality of the content is the highest consideration. The objective is to maintain all the information in a PDF file that a commercial printer or print service provider needs in order to print the document correctly. This set of options uses PDF 1.4, converts colors to CMYK, downsamples color and grayscale images to 300 ppi and monochrome images to 1200 ppi, embeds subsets of all fonts, and preserves transparency (for file types capable of transparency). These PDF files can be opened in Acrobat 5.0 and Acrobat Reader 5.0 and later." ¹

Smallest File Size — This setting is intended for proof files sent over the Internet to be viewed on a computer screen. It uses a very high rate of compression on images, downsamples them to 72ppi, is not intended for printing, and should never be sent to a professional printer as anything other than a proof.

WARNING — While most of these pdf preset downsample images to 300ppi, PDF PRESETS DO NOT CHECK TO SEE IF YOUR IMAGES ARE 300ppi OR LARGER TO BEGIN WITH. If your images are less than 300ppi at 100% (the standard for professional printing) before creating the pdf, they will not magically be made 300ppi at 100% by conversion to pdf, and will print soft or pixillated on press. The printer is not responsible for this. Always check your image resolution before conversion to pdf.

PDF Options

There are additional options when making pdfs other than those directly available from these presets. Some things to be aware of:

• When you go to make a pdf, the first window will ask you where you want to save the pdf and what to name it. The second window gives you an Options page, including a list of deeper options on the left.
• These pdf presets output single-page pdfs. If you want to send a proof that shows reader spreads, there is a checkbox on the Options page under "Range."
• Crops and bleeds aren't automatically added with these presets. You will find the crops and bleed options on the left column of the Options page under "Marks and Bleeds."
• Many professional printers have specific pdf requirements. Ask them which preset they want you to use. They may have their own preset, in which case ask them how to install it.
• Sometimes you want to restrict people's ability to copy or print from your pdfs. This can be controlled under "Security" on the Options page. Just be sure to keep track of any password you create.

Creating Your Own Presets

File>Adobe PDF Presets>Define. Select the profile you want to base yours on, and click New. Make changes to the presets, create a name for your preset, and click Okay. The new preset name will appear in the list. If you are basing your preset on another, it's good to include the original name as part of the name.

¹ Source: Illustrator / Creating Adobe PDF files