Using Photopolymer Plates
If you are looking for a do-it-yourself method of making molds with computer graphics or logos, you may want to try using photopolymer plates, also called printing plates. See discussion Plates & Dies for general information. Printing plates can be used to make a relief image. The plate with the image is then mounted on a base which is in the shape of what you want your custom chocolate to look like. For example, if you wanted to make a chocolate business card, you would first make the shape of the business card, then take the finished photopolymer plate and mount it to the business card shape. You can make the base shape by taking a blank chocolate mold and filling it with plaster, clay, or some other material. Then you would use one of the mold making methods, such as silicone rubber or vacuum formed plastic.
So how do you make the photopolymer plate? Well, first you must decide what type of plate to buy. You will need to decide how much relief (how high the letters or image will be) and what type of material do you want the photopolymer on. This will depend on your mold making method. For example, if you are going to make a silicone rubber mold, you can use a plastic backed photopolymer plate with a low relief. This is due to silicone's ability to pick up great detail. However, if you are going to make a vacuum formed mold, you are going to need a plate with a higher relief, is metal backed, and can withstand higher temperatures. This is due to the fact that vacuum forming cannot pick up as great of detail as silicone, and it requires the materials to be able to withstand heat. One company that sells photopolymer plates that can withstand heat is RB-Cor's product called Rigilon. Photopolymer plates come in varying reliefs, so you will have to find one that works best for you and your methods. Also, if you are going to be doing this at home, you will want a photopolymer plate that can be washed out with water.
Now, one word about buying photopolymer. It can be very difficult to find someone who will sell you small quantities. Some arthouses do sell photopolymer with low relief. Try to stay away from large printing company suppliers if you don't want to buy say at least 10 pieces.
Ok, so let's say you have your photopolymer, how do you get your image on it so you can make a mold? If you ask any printing plate company, they are going to tell you that you need thousands of dollars of plate processing equipment, but that is not true. All you will need is the following: a pure black and white computer image, transparency, a UV light box, a plate holder, a soft washout brush or toothbrush, newspaper, paper towel, and a hair dryer. Then follow these steps:
Print the image on a transparency, preferably with a printer that can print at least 1200 dpi black. It is very important to make sure there is no light shining through on the black, even a microscopic dot can cause major problems. If you do not have a printer that prints 1200 dpi, you can use a printer with 600 dpi and spray it with some art fixative a few times to help.
Cut the transparency and the unprocessed printing plate to be the same size. Make sure to limit the amount of time you work with the unfinished plate because it will not take too much light exposure to ruin the plate. Film backed and plastic backed plates can be cut with scissors. Metal backed plates can be cut with a pair of really good shop scissors, a good paper trimmer, hand nibblers, shears, or a nibbler attached to a drill.
Put the transparency on the plate and put them both in a plate holder. You can make a plate holder with a piece of wood or cardboard, a piece of glass, and some binder clips. Just sandwich the plate between the wood and the glass, and hold it all together with binder clips. It is very important that you make sure the transparency lays perfectly flat on the plate.
Wash out the plate using water at the temperature specified by the manufacturer. It is best to use a washout brush, but you can use any type of brush that is soft. A toothbrush works great. Try to use the least amount of water as possible and work fairly quickly. In short time you will see your image starting to look like it is raised. Keep working until you are left with only the image and the plate backing material.