Preflighting is an essential part of print advertising as it reduces the margin for error – simply put, it is a quality checking process for PDFs before they are processed.

With traditional artworking skills on the decline, it’s a good idea to have the occasional reminder about issues that affect the way an ad prints out.

Today’s press processes smooth out many of these issues by automatically fixing the files, but it’s best practice to get your files just right in the first place, because these automatic changes may not be what you want. Why run the risk? Here are the 6 most common problems that you should look out for to ensure your ad goes to print just as you planned.

1. Color Models

Industry best practice is to work in RGB for as long as possible, before converting to CMYK for printing purposes. A common problem is when that last conversion step does not happen in the studio. A publisher may reject a PDF provided in RGB, or attempt to convert it to CMYK.

Since you will not have control over this conversion, you may find the printed ad has undergone significant color shifts that may breach your customers’ brand management guidelines.

Tip: View our free eBook on the color management process and for more detail about this mistake and how to easily prevent it.

2. Low Res Imagery

Your computer screen doesn’t work the same as a printer. An image in low resolution might look pretty presentable when laid out on your screen, but printing requires significantly higher resolution images if the results are to remain sharp and unpixelated. There have been too many instances when an ad that looked good on the computer screen appeared on the page with the images blurred or marred by the digital artifacts from upscaling them.

Tip: Avoid manually scaling your images up in Photoshop; you’re just adding pixels that don’t exist. Always source the highest resolution of an image you can find to start with and scale them down as needed.

3. Transparent Images

With the digital workflow today, it’s hard to notice if you have inadvertently sourced and placed a transparent image in your design — they all look the same on the screen! But once the PDF file (with the embedded image) gets to the printer, this becomes a serious issue: the transparent parts get printed in an opaque color, or some other substitution occurs. Either way, your printed ad can look completely different to what had been originally designed. There is also underlying software compatibility issues.

Tip: To ensure you are not using transparent images in your design, the blog PrePressure gives a small breakdown on how you can prevent it.

4. Non-embedded Fonts

When you create a PDF file of your document, you need to make sure your fonts are embedded within in the PDF file. This ensures that the fonts you intended to use are shown on the document you’ve sent over. If not, the person who opens the document (and does not have the font you used) will receive a warning – and the system may choose to automatically replace the perfect font you used with the closest equivalent that it can find.

5. Bleed

Unlike files destined for digital display, print ads need margins to account for the physical process of printing and trimming. The bleed extends past the trim edge so that the final, trimmed page, has colors or images that go to the very edge of the page. Be sure to look up the bleed, trim and safe edge specifications of the printer and include these in your document. Be sure not to include any essential design elements or information in the bleed and trim areas.

6. Corrupt Fonts

It’s always sad when a good font goes bad, and this may be because the font file is corrupt or damaged, before you’ve even started designing. It may also be the case that the font hasn’t been embedded properly within the PDF document. You will normally find that the issue occurs once the file has been exported – leaving you with a whole host of problems.

Tip: Check your files by opening them in another terminal that doesn’t have that font installed natively. PDF preflight checks offered by tools like Adobe Acrobat Professional can also pick up such issues. If you have recurring issues with corrupted fonts in your exported files, you can also try using FontDoctor which will help diagnose and repair your fonts.

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Read More: Things to Check in Press-Ready PDF