At B Direct, we've always loved postcards. And there are two very good reasons to use them today:

• They stand out in a crowded mail- or inbox.
• People's attention spans, which were never as long as we marketers would like, are shorter than ever.

We recently received a full-color and generous-sized (6" x 11"!) card from Square, encouraging us to use their "all-in-one POS for booking, payments, and team management."

The address side includes a small business photo of a barbershop with vintage chairs and — bonus — the company dog lounging on the floor. Teaser copy instructs us to "Turn followers into customer" and continues, "Over 70% of appointments booked on Instagram through Square Appointments are from new customers." A graphic demonstrates that the app is "Available for the front desk or on the go," with images of the app on different devices.

The message side headline reads. "Simplify booking with Square Appointments" and there are two photos of users engaging with the app. Then there's a quite a lot of features and benefit copy. A call to action: "Learn more at square.com/get/appts" is matched by logo tikes for the Apple AppStore and Google Pay.

All in all, this is a nice campaign. Except for two things:

• B Direct is NOT a prospect for this service. (Sorry, not how our business works.)

And

• Why (oh why) did they reverse out all the body copy?

David Ogilvy (1911-1999) once said "Never reverse out advertising copy." Magazine publisher, and author of Type and Layout, Colin Wheildon tested this theory. He used a serif font in different ways and measured reading comprehension:

• Black type on white: Good 70%, Fair 19%, Poor 11%
• White  type on black: Good 0%, Fair 12%, Poor 88%

When he used a sans serif font, comprehension was even worse. And guess what our friends at Square are using?

'Afraid we have to give the postcard a thumbs-down, based mainly on readability.

(We still haven't finished reading the body copy and probably won't.)