Let's indulge in a flashback. It's third-period math class in the seventh grade. Off go the classroom lights and out comes the old-school overhead projector. Your teacher lays down an acetate sheet and the equation "3w + 5 = 8" is projected onto the whiteboard. She calls on you to fill in that "w," handing you a dry-erase marker that smells like old nail polish remover just as you remember you're really, really bad at math.

As a grown-up small business owner, it's time to overwrite those awkward memories. Acetate sheets, sometimes called acetate film, still have a place in today's business world, no matter how niche. Sure, sending your presentation from your smartphone's PowerPoint app to a 65-inch, 4K Android TV via Bluetooth is neat, but sharing info with a good old projector and acetate sheets is a lot cheaper, not to mention their potential for crafty in-store displays.

And the best part? You don't even have to worry about Wi-Fi.

What Are Acetate Sheets?

Acetate plastic is formally known as cellulose acetate. It's made from wood pulp, cotton fibers or a combination of the two, which is then mechanically formed into thin, flat sheets using a solvent or forced extrusion. This gives it a very uniform, glass-like transparency (though it can also be made with a matte finish) and a lightweight form factor that can easily be cut into custom shapes. For business applications, this acetate film is most often used in an A4 letter format measuring 8.5-by-11 inches and laid on bulb-powered overhead projectors to emit a projected image onto a large surface. Acetate sheets often work with dry-erase markers, meaning they are easily customizable and reusable. However, acetate sheets – also known as acetate paper or transparencies (yes, they go by many names) – also have medical and culinary applications.

As of 2018 prices, write-on, letter-sized acetate sheets for use with overhead projectors go for about $40 per 100 sheets at big-box retailers. That comes out to only about 40 cents per reusable transparency.

Using an Overhead Projector

Most overhead projectors work with letter-sized transparencies, which you lay atop the large sheet of stage glass on the projector's body. You don't have to worry about writing backward or anything like that – the projector's system of mirrors and condenser lenses project the image on the sheet as drawn or written. Placing the projector closer or further from the projection surface will make the image larger or smaller, sharper or softer, and you can adjust the focus in detail using the machine's focus knob.

You can write freehand on your transparency with a water-based pen or marker. Bold text and images work best for projection; trace over images printed onto paper if you need a hand. Once you're projecting, be sure to stand off to one side of the projector and face your audience. To quickly cover a transparency without having to turn the machine off completely (which takes longer and can wear out the bulb), just cover it with a piece of opaque cardboard.

Ideas for Repurposing Acetate Sheets

If you've somehow come across a cache of acetate sheets but have no overhead projector (or are totally content with your Bluetooth-smartphone-smart TV projecting setup), don't bin those transparencies just yet. A little clever repurposing can make for a trendy, retro-cool addition to your small business.

If you have an artistic side, grab some high-quality illustrating markers with alcohol-based ink. Got a 40-pack of acetate paper? Now you've got 40 store signs. These transparent signs can be displayed on windows for a clean, minimalist look or layered on to other displays for an eye-catching, 3D effect, like a little shadowbox of advertising.

Want to get even more vintage street cred? Go ahead and track down an overhead projector. Whether at a local Goodwill or on eBay, it's not uncommon to find these charmingly dated devices in the $30-to-$60 range, often with a fully functioning lamp included so you can just plug and play. If you have a little clean wall space and some illustration or calligraphy skills, you'll have an eye-catching (and extremely affordable) way to display your daily menu, current specials or product price list, with a minimum of fuss when it's time to change the info. This life hack works especially well in quirky small business spaces, like vintage stores, coffee shops with daily menus, or – appropriately so – in your burgeoning handmade stationery boutique.