The Ziflow Blog

Posted by Anthony Welgemoed

A Common Pitfall to Avoid in Online Proofing

After spending over 10 years building online proofing systems, and even more before that spent building software for marketing teams and agencies, Mat and I have been asked time and again what makes us different from other applications and, even though there’s a lot we can talk about, we always come back to focus and quality.

In this blog post, I’d like to talk about quality, and in particular PDF processing for review and approval. This also applies to other Adobe file formats being processed for review, such as AI and PSD files.

Ziflow, and most online proofing vendors, convert the source PDF during the proofing process, and although we aren’t claiming to deal with color accurate proofing, Ziflow values quality so much, we spend a huge amount of effort in ensuring that the file you upload for processing is represented as accurately as possible.

You might be surprised at the results when you compare the quality of PDF conversion in different online proofing applications, and since we’re in the business to save you the time, we’ve provided an example of a real-world comparison for you. You can also use this as a step by step guide to compare the quality of other online proofing tools.

First, download and upload a suitable test file

The European Color Initiative (ECI) launched a project called “Altona Test Suite 2” with the purpose “to exercise features in the PDF language that have become relevant on the background of the publication of ISO 15930-7 (PDF/X-4)”. Simply put, when processing a PDF file, applications need to ensure they handle all PDF capabilities. This makes it an excellent file for testing PDF review and approval capabilities.  

You can get the test file here and upload it to any online proofing system.

Comparing Results

ECI has conveniently created documentation that explains what the result should look like, you can find the file here.

Now let’s see how Ziflow compares in a sample real-world test.

In all the screenshots Ziflow is on the right and another unnamed proofing application is on the left.

Patch B

A subtle diagonal line shows how the gray appears darker above the line. If this happens, transparency isn’t handled correctly.

Screen Shot 2018-02-21 at 7.46.57 PM.png

Patch C

This patch tests knockout within a transparency group. Apart from the poor quality of the conversion in our unnamed application, the knockout also shows clear gaps in color.


Patch D

The patch tests how a system deals with color management capabilities. The easiest way to explain what the result should look like is to show you the expected output, and then the results.

Expected output:


Results: In our unnamed vendor’s application (on the left) the first three rows clearly show a lack of quality.

Screen Shot 2018-02-21 at 8.00.41 PM.png


Patch F

Proper font handling is often a challenge during the conversion process. Here we show how our unnamed vendor fails to convert text that was converted to outlines in Photoshop and InDesign.



Patch G

The patch tests the use of various shading and transparency effects. As you might expect, our unnamed vendor’s result differs drastically from the expected result.

Expected output:


Results: Apart from every square being different in our unnamed vendor’s application, here I’d like to point out the most obvious ones.



Patch M, P

Finally, patches M & P show a few other elements that can go wrong during conversion. Without getting into too much detail, Ziflow’s resulting proof on the right is the correct one:




Why does this matter?

You might be thinking, does this even matter to me and my organization?

I’ve personally seen hundreds of support tickets where we ‘catch’ the incorrect use of overprint and knockout, saving a client thousands of dollars in an erroneous print run. Then there are the countless hours saved in avoiding the back-and-forth discussion between reviewers and our customers addressing comments about colors displayed in a proof, only to find the originally uploaded file actually shows the correct color but the proof wasn’t converted properly.

And as a final thought, if your online proofing solution provider sweats the small details such as this, you can rest assured they will spend all their energy on the things that matter to you - providing you with the best online proofing solution possible.