PDF Creation Specifications

This page provides information regarding PDF formatting and optimization, as well as a process for creating the best black and white images for print.

1)Aways Embed fonts - if your pdf has text, Always embed the full font family. If at all possible, DO NOT SUBSET FONTS

• If a font is multiply subsetted in a pdf, when presented to the rip, can produce garbled text. The RIP seems to try to build a single font resource for a multiply subsetted font. But since that font has multiple definitions in the pdf, the font resource that the rip builds can be at the very least garbled from being overwritten over and over again. Furthur, The RIP might reject the font resource entirely, and end up substituting Courier instead. This Usually produces expanded text, reflowing due to expanded kerning.
• If a pdf file is built from multiple other pdf files, and fonts are subsetted in those individual files, then when they are combined, the final PDF file will have multiply subsetted fonts, which can produce this issue.

So, if you fully embed, and never subset, there will be one and only one font definition in your final file.

2) Optimize for Fast WebView
3) Compatability: Recommend Acrobat 5
4) If available, Leave Colors As is {Leave Colors unchanged}
5) Image Compression: Color

• Zip, {lossless, but might create huge files}
• Use Jpeg High -> Low to lower filesize {Lossy, but reuces file size}

6) Image Compression: BW

• Aways ZIP Greyscale images, do not use CCITT

7) Do not downsample images, Unless:

• If your pages are fully rasterized, if their DPI > 300, Downsample to 300

8) Compress text and Line Art
9) Do not preserve OPI comments

• Certain PDF Tools, such as Pitstop, have problems otherwise.

10) File Sizes should be < 700 MB's , preferably no more than 101 Mbytes.
11) Make sure Overprint is off
12) USE CMYK or RGB Colors in Paths that are below Transparencies. Spot colors that are below an images transparency might not print.


Bleeding the Document:
1) Have bleed @ 1/8th symetric all around
2) Have Optional Marks offset 10 points
3) If you want bleed in your document all intended bleeding elements must extend beyond the document size by at least 1/4th of an inch total in both directions (1/8" on each side).


Image Files:
1) Do not change the colorspace of an image file, ie… if your original image file is in RGB, DO NOT CONVERT it to CMYK.
2) Do not use images with CCITT compression.
3) Do not use images with LZW compression, if at all possible.
4) Images that are Multi-Strip can print with lines between the strips. LZW is one image compression that can produce Multi-Strip Image files, especially on TIFF images. Do not use images that are Multi-Strip, but are continuous.
5) Do not use "Artificial" Greyscale, ie… RGB or CMYK images with near matching channel values. If an image is meant to be Gray, its color space should be gray.
6) The DocuSP is optimized to best print GrayScale images whose "Gamma" is between 2.2 and 2.4. If your greyscale images have a Gamma of 1.8, they will print too dark.
7) Image DPI, in its final document dimensions, should not exceed 600 dpi, and preferably should be about 300 DPI, to optimize RIP speed.

For PDFLib Users:
JPEG Files: - If a PDF file fails to RIP, and the error message is that this was due to an invalid JPEG Marker, and this is NOT due to a corrupt image {Adobe Acrobat usually pops up a message if an image on a page is indeed corrupt} then it is recommended that you use the "passthrough false" option when you are performing a load_image command.

PDFLib recommends you contact support when such an issue occurs, and provide the image that requires this "passthrough false" option, so that they can develop against this new jpeg flavor in future releases.

NOTE: CMYK, as placed by an iGen, from the Upper Surface to the lower Sheet of a printed document, ARE: MYCK. M, being on top, will be most noticable.