Printing and Design Tips: July 2013, Issue #144

Printing on a Sheet Cake or Cookies

Assumptions tend to be wrong, and sometimes they're downright comical. When I heard of a relative's upcoming birthday party and learned that his photo would be inkjetted onto the cake, I had images of a large-format inkjet printer with an array of print heads passing down the length of a sheetcake, spraying food-grade coloring onto the icing. I wondered how high the print heads would need to rise above the surface of the cake.

Needless to say, I was wrong. Fortunately, it's much easier than this, and you can use a regular inkjet printer.

Here's the process:

  1. You buy specially formulated paper made of rice flour. It is edible and tasteless, and it comes on a plastic backing sheet, which you peel off after printing and before applying to the food.
  2. You buy specially formulated, edible inks. These are FDA approved food coloring. They can be added to refillable cartridges used only for edible printing work.
  3. You buy an inkjet printer that you will specifically dedicate to food printing so as to avoid contaminating food inks with regular inks and vice versa.
  4. You print your photo on the rice-flour paper. Alternatively, you can draw the image with food coloring using a pen.
  5. After you have baked the cake or cookies, you cut the appropriate sized inkjet printed image sheet, remove the backing, brush the back of the paper with water, and lay the image onto the cake or cookie with the image side up.

The key here is to apply the sheet after baking, not before. Laying a printed rice-flour paper sheet onto raw cookie dough and then baking the cookie might change the color of the food dyes, yielding unexpected results. So wait until the cake or cookie has cooled, and then apply the printed sheet.

The printed rice-flour paper will soften and blend into the cake icing. Choosing a printing sheet that will do this is important. Otherwise, you will have a stiff layer on top of the icing, and this may be less appetizing. (I'd suggest doing some research online.)

As you are researching materials for cake printing, look for a substrate that is not only made from rice flour but one that comes recommended as stable, clear, and with good ink holdout (make sure the inks will sit up on top of the sheet and not seep in).

Keep in mind that even the paper is a food product. You can print on it, but I'd suggest using all the sheets at one time or making sure the bag reseals. Otherwise, the paper will go bad just like any other food product.

The good news is that this is fast and easy, if you have the right materials and if you understand the process. Even better, it's very dramatic, particularly if you choose a good photo. My relative was surprised and touched when he saw his birthday cake. After all, who doesn't like a good photo of themselves?

And if you don't want to do this yourself, there are multiple vendors out there who will charge you almost nothing to add the cost of inkjetting to the cost of the prepared sheet cake.

Organic Food-Grade Inks

Edible inks are FDA certified products made from “food-grade chemicals.” That said, you don't have to use chemically-based food colorings if you're willing to experiment a bit.

I just read an article listing some common foods that will yield bright colors, and since they are not chemically based, you minimize the risk of any health problems.

For orange, you can use juiced carrots, which will also add sweetness to the food coloring.

For green, you might try liquid chlorophyll, which can be purchased at health food stores. You might also try spinach, which actually does not add taste to the food ink mixture.

For purple and blue try blueberries or blackberries. Alternately, you can boil red cabbage and use the purple juice that results, or you can add baking soda to the purple juice to make a blue coloring.

You might want to try turmeric or saffron to make yellow food dye. These may change the taste of the mixture, so test the food inks you're making.

For pink or red, you can use beets (canned beets, or boiled or juiced raw beets). These have almost no taste. Alternately, you can use strawberries or pomegranates, but these may add a different taste to the food coloring. If you want to use strawberries or pomegranates, you can juice them in a blender and then strain out the red coloring.

Once you have the colors, they can be put in refillable inkjet cartridges (check online to find out where to buy these cartridges and how to refill them).

These colors will not be as vibrant as the chemical food colorants you can buy. They may be more pastel in their hues. In addition, you're not going to be starting with a CMYK inkset (cyan, magenta, yellow, and black). So you might need to experiment a bit. But you'll be ingesting healthier food-grade inks in the process.

[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]