As a support associate here at Bronto, I not only help to support our clients, but I do my part to support my fellow Brontos as well. One of the things that I am responsible for is testing all of Bronto's marketing emails in the major email clients, just to be absolutely certain that our messages are being seen as they are meant to be.

All in all, this is a fairly simple task – send a test message to a number of people in our office who use the different email clients, and make sure it looks like it is intended to look. However, a couple of computers always gave me problems, both of them used Outlook 2007, and both of them mangled our normally nice looking emails. To add to the mystery, the two bad seeds would break the messages in totally different ways.

All of the other instances of Outlook 2007 in our office rendered the message just fine, so we would normally chalk it up to a setting on the computer that was making the messages render incorrectly. Some people may be able to walk away from a situation like this; I am not one of those people. This would not stand… not on my watch.

I decided to do some research and testing to see what exactly was causing this error. I settled down with the two machines to see what I could find. I looked through all of the settings that I thought could be causing the issue in Outlook 2007, but even with all of the settings the same, the messages still did not render correctly. This is when I noticed the two computers side by side just didn't look the same, everything was much bigger on one and much smaller on the other, and this led me to check the graphics settings, which in turn led me straight to the culprit... the DPI setting. 

According to Wikipedia, DPI (Dots Per Inch) is a measure of printing or display resolution, in particular the number of individual dots or pixels that can be produced within a linear one-inch (2.54 cm) space. The default DPI on a Microsoft Windows machine is 96. One of the offending computers was set to 120dpi (large) and the other was set to 82dpi (a custom setting).

This drove me to run some tests on a larger scale to make sure I was on the right track – here's what I did: I took 6 computers; each with Outlook 2007 and Mozilla Thunderbird installed and sent them a copy of the Bronto News. First, I set each of the computers DPI to the default setting of 96, then I checked the same message with the DPI setting changed to 120, and finally, I changed the DPI to 82 and looked at the message again.

The results are extremely insightful: Outlook 2007 choked on anything except for the default DPI, while Thunderbird displayed the message perfectly no matter what the DPI was set to.

Could your contacts DPI settings be causing your messages to display improperly? The answer is a resounding yes, which is definitely something to think about when conducting your testing.

I'll be continuing my research to see if there is something that we as email marketers can do to work around this issue. Look for my next post in May, and if you've come across this in your campaigns, please feel free to leave a comment.

Lucas Weber
Support Associate at Bronto