We make use of one of two technologies when we print on brown and white bags. One is flexprint, the other is digital overprint.
Flexprint makes sense when it comes to larger deliveries (several pallets) of a single paper bag format.
Digital overprinting makes sense when the order is relatively small. It can be from a few hundred and up to 5-10,000, depending on the format of the bag. Especially when the customer wants multicolored print because the price does not depend on the number of colors and because the purchase of cliché plates is not necessary.
Flexprint is a well-known technology in this context. Here, the unit price of the printed bags depends on the number of colors, the percentage color coverage of the printed bag, the size of the bag and the magnitude of the order. One cliché plate per color is required.
Digital overprint is a new and lesser known technology, which requires an explanation if one is to understand the technology’s special possibilities and limitations. The main advantage has already been mentioned: it is realistic to print small editions in multicolor printing at low prices.
All the following is only relevant for digital overprint:
Water-based CMYK colors are used for digital overprint
It is the CMYK technology that makes it possible to print in many colors without the price running wild. Overprint works in such a way that a bag passes under a waterfall of colors mixed of just four basic colors, CYAN (C), MAGENTA (M), YELLOW (Y) and BLACK (K). A file with the desired motif signals to the overprinter when the “waterfall” opens and closes, and the bag with motif comes out.
The colors are not 100% waterproof, so the colors risk running if you spill coffee on the bag, for instance.
You cannot mix the color white of the four CMYK colors. Overprint is usually not suitable if, for example, you want to print your white logo. White signals to the printer not to open the “waterfall”, and therefore the basic color of the bag will replace the white. If the bag is white, the problem may be solved.
CMYK overprint on white bags
Motifs in many colors and with many details look very nice on white bags. Floral motifs can be an example, and digital overprint is also well suited for illustrations and photos up to a certain level of quality.
On the other hand, large solid-colored surfaces on white bags do not always work well.
CMYK overprint on brown bags
Black works well on brown paper.
Green, blue, purple, and generally saturated colors with deep shades work well on brown paper.
Yellow, orange, and pink colors should sometimes be test printed in advance, as some mixtures may be disturbed by the brown base color of the material.
The print area depends on the size and type of bag.
It is not good to print on uneven surfaces. Thus, if the bag has handles, it is not possible to print on the places where the handles are mounted, and normally only the front of the bag can be printed.
The digital overprinter’s print head extends over a maximum of 223 mm. This means that a maximum of 223 mm can be printed in the height of the bag, while in practice there is no upper limit in the width of the bag.
The printing begins with a vectorized file, which will typically be in pdf format.
There is nothing stopping a file from filling many pages. Thus, the customer can deliver a file of e.g. 100 pages with different motifs on each page (e.g. numbering or a merged file with 100 different names).
Of course, this means special customization opportunities for e.g. PR and communication agencies. Yellow, orange, and bright reddish colors should be tested in advance, as some mixtures may be disturbed by the brown base color of the material.