Actual watermarks are a feature within the fiber structure of the paper itself. Which means they’re created during the manufacturing process. Of course, we’ll have to go through too much trouble if we tried to create our own paper from scratch so we’ll need to “imprint” a watermark onto ordinary copy paper.
A watermark is basically a location on the paper where the fiber layer is either thicker or thinner than the surrounding area as to allow a variation in the amount of light transmitted through it. I.E. Where the paper is thinner, the line will appear brighter as more light can pass through it. Where it’s thicker, it will appear darker. So we either need to shave off a thin layer in the shape of our symbol on the surface of the paper or add on a thin layer.
Shaving off is a lot simpler…
For this procedure, we’ll need a flat surface, a glass container, a stensil or stamp of our watermark symbol, a rag. Alternatively, you could use a sharpened chopstick or other thin wooden instrument if you want to sign your watermark yourself.
And we need a watermarking agent… Drain cleaner will do nicely.
The reason we use drain cleaner is because of the Sodium Hydroxide content found in most brands (commonly known as lye or caustic soda). The concentration isn’t strong enough to be dangerous, as pure lye will cause severe chemical burns, but it’s still strong enough to have an effect on the cellulose structure of the paper. And it’s easily available. In fact, you probably have some right now in your bathroom.
There is some debate as to whether lye actually “dissolves” cellulose or merely expands the fibers. Either way, it works pretty well as you only need to change the structure of the paper until light shining through will reveal a particular pattern, for it to be considered a watermark. And, considering drain cleaner has additional ingredients to dissolve obstructions such as toilet paper, It’s a win-win situation either way.
Drain cleaner may cause skin irritation in some people, so gloves are highly recommended. If you’re prone to accidents, a pair of goggles or wrap around sunglasses, if none are available, may also be a good idea.
“Orange Glo” floor finisher can also work as a watermarking agent without destroying the paper, but the oil content will make it visible even without holding it up to a light. It won’t be a true watermark.
First, take a test print of your layout. Figure out where you want to place the watermark based on your layout. Ideally, you want security features to overlap so if you included any complex logos, then place the watermark on the same location.
Place the paper to be watermarked on the flat surface. Dip the watermark stamp into the glass container with a small amount of drain cleaner on the bottom. Shake a bit of the excess off (it should be wet, but not dripping) and firmly place the stamp on the paper. Make sure you don’t leave the stamp on longer than 2 seconds. Repeat when dry, if necessary.
Dry off the stamp with the rag and repeat with the next sheet of paper.
Alternatively, you could place a cutout stencil of your watermark over the paper and use a spray bottle to apply the drain cleaner, but then you definitely need goggles and gloves. I’m not sure how defined the lines will be with this method.
After you’ve created the watermark, it’s time to print the paper. Let it dry for at least 30 – 45 minutes before printing.