One of the trickiest things about designing for print is understanding trim size and all things related to it.
After the printed pages come off our presses and are bound together, they need to be “trimmed” so that each page is exactly the same size. This ensures each page in your publication is even, giving it that professional look.
While we always try to trim as accurately as possible, it’s natural for the trim line to vary slightly in one direction or the other, which is why we recommend that you include a “bleed” and work within a “safe zone” when you design your PDF.
Bleed
To ensure that no important parts of the page are cut off in the trimming process a “bleed” area is defined. The “bleed” extends beyond the “trim” for when you want a photo or color to extend to the edge of the page. For Standard, Digest, and Digest Landscape publications, the bleed is the top 0.125 inches, the bottom 0.125 inches, and the outside 0.25 inches of your PDF. For Flyer publications, the bleed is the 0.125 inches on all sides of the 8.5″ x 11″ PDF.
The reason to include a bleed in print files is to ensure that images you want to go to the edge of the page always do so, regardless of how exact the trim is. If an image is cropped at the 8.25” x 10.75” trim edge on a Standard size publications, as shown in the below diagram on the left, and the print is trimmed slightly wider, then there will be a white bar between the printed image and the edge of the page. If the image is extended all the way to the 8.5” x 11” PDF edge instead, filling the bleed area as shown in the below diagram on the right, then the printed image will go all the way to the edge of the page regardless of where the actual trim occurs.
Safe Zone
The “safe zone” is the area inside the trim line where your text and graphics are not at risk of being cut off or lost into the binding in the final print, regardless of any variation in the trim. For MagCloud publications this area is 0.25 inches within all sides of the trim edge.
Any content that you want to appear completely within the final printed publication should be kept inside the safe zone. Placing content too close to the top, bottom or outside edge of the PDF could result in that content being cut off during trimming. This is something to keep in mind when adding page numbers to your publication, as those tend to be placed closer to the page edge. Similarly, placing content too close to the inside edge of the PDF could result in that content being lost into the binding if your publication is perfect bound. By keeping your content within the safe zone, you ensure that it will appear completely in the final print and digital copies of your publication.
For more information and step-by-step instructions to set up your PDF with the bleed and safe zone in mind be sure to check out our Getting Started page.
Next up in the MagCloud Design series: The Importance of Layouts and Templates
Publisher's Corner 
The trim specs listed above for the “Standard” saddle stitch pamphlet is not correct because you would be printing these as spreads. This makes it very confusing for file prep. Please reconcile that as it isn’t that easy to contact you guys for general questions such as this.
Also, I’ve never heard of a 0.5 in. safety from trim. Industry standard is 0.25 at most and some places use 1/8 or 0.125 in. Needing a 0.5 in. safety from trim indicates perhaps that your process is not robust or accurate?
Hi Samantha,
thanks for your message. Currently our system is designed to only process single pages uploaded in the PDF – although they will be printed as spreads. We’ll look into the possibility of handling uploaded spreads in the future as a new feature for our uploader.
With respect to the 0.5″ safety area we are considering changing this sometime in the near future to .25″ to be consistent with Blurb’s (our parent company) safety area.
Cheers,
Brady