You are probably wondering why anyone would print something twice. It is done primarily to have your company name, logo and other information as a background and then you can print other one-off information on top of the previously printed material.
The most common example is your business letterhead. Many businesses have these pre-printed and then the letterheads are run through an inexpensive laser printer with your letter to your client, supplier, employee or other important person. Businesses do this form of double printing because they want their company name, logo and other pertinent information in the highest possible quality. Then, the other information is printed in a lower resolution.
The same principle applies to the process of double label printing. Businesses would like their brand name, logo and other important information printed in the highest possible quality whilst detailed information including product identification and ingredients are printed separately in a lower resolution on a relatively low cost label printing machine such as a thermal transfer printer. This process is used when the information varies. This includes the situation where a small business will have multiple products in multiple sizes and does not want to print a label for each variation but also wants the brand and logo other information pre-printed in the highest quality.
These product labels are printed in two runs. Firstly, the brand name and logo, etc are printed with ample room for the product details to also be included under the brand name or business name and logo. Typically, these initial labels would be printed on letterpress or flexographic machines. The labels are printed this way if the run is long, say, well over 10,000 labels. The setup fees are expensive with plates printed for each colour. For four colour process labels, four plates are needed. However, the printing is very fast and hence, cost effective for long runs.
With digital label printing technology getting more advanced every year and the labels printed faster and faster, then it is now possible that the pre-printed labels would be printed digitally, without the need for expensive plates.
These labels would almost always be printed on rolls and they would have to be produced in a way that suited the machine that was overprinting the originally printed labels. Such things as the space between the labels and the width of the label will be important.
Now, if you order cold meat or fish or sushi at your local supermarket, then you would have seen the labels actually printed in front of your eyes. However, the stock used is a blank white label stock. Well the overprinting is very similar. It is just that the labels will not be blank. They will have the business name or brand name on the label and this is important for repeat sales.
Typically, this form of overprinting is used in the food industry but it could also be used in the cosmetics industry or any industry where businesses sell a wide variety of products under the one brand or business.
Here is an example from the food industry. Suppose you sell several jams and condiments in different flavours and sizes. You may wish to highlight your business or brand name on every label and just alter the details in relation to the ingredients, size and flavour. If you are doing this, then you must familiarise yourself with the new laws pertaining to food labels that come into effect on 1 July, 2016.
The process of double label printing is not used often as digital technology now offers cost effective solutions for short run label printing but my conversations with food producers last month suggests that this practice is still quite widespread.