As part of running events, we frequently have customers supplying artwork for their badges. There's some basic guidelines that should be considered when laying out your badges, here's an outline any event organizer should use when designing badges.
Stonekeep uses CR80 (credit card sized) badges for all events. The badge printers are relatively inexpensive, the badge stock is easy to come by, and the size is convenient for all attendees. Note that even though CR80 badges are relatively small compared to some other formats (say, 3x5 cards, or large scale badges used in big venues), the print quality on them is excellent, with vivid colors and high contrast artwork that shows up well during final printing.
Because the badges are CR80 form factor, the size of the artwork is fixed to 3.37 in x 2.125 in. Modern badge printers can print 'edge to edge', so that entire surface is available for use. When submitting artwork, it should be delivered in high density (300dpi) PDF, PNG, or Photoshop format. Most print shops prefer Photoshop files for their batch runs.
To speed the registration process, we have the badge 'blanks' printed professionally ahead of the event, with the expectation that we will be printing attendee names and other information on the fly at the event. This means the badge printers for the event need only print in one color (very fast), while still delivering an attractive, collectible, and indelible badge to the attendee.
When designing badges, consider what is the most important information to display. The most space on the badge should be taken up by the attendee's name and, in professional situations, their company. CONGO supports a 'badge name' field, which allows the attendee to specify exactly what text is displayed on their badge (ie "Bob the Kangaroo" instead of their legal name). In addition, many events will have the badge ID or the attendees full name printed in a smaller font elsewhere on the badge, for validation / verification purposes.
It's important to leave space in the badge artwork for the attendee name and company name, as well as other information. Dark colored badges will not let the text of the attendee name stand out well. Narrow spaces will make it difficult to fit longer names in without hyphenation. All of these issues can be addressed as long as the artist knows about them ahead of time.
Lastly, a frequent mistake in badge design is printing the event name too large. Every attendee knows what event they are attending, they don't need a third of the badge displaying the event name.
Badges are frequently kept by attendees as 'souvenirs' of the event. High quality artwork and smart layouts leave a lasting impression.