How to properly prepare files
for flexographic
and digital printing.
The specificity of flexographic printing differs from the more popular offset printing technique. Flexographic printing, the so-called Roll printing. is characterized by a relatively fast reflection rate of polymer matrices on long material ribbons. This guarantees 100% color repeatability and makes all labels on the roll identical. Receiving designs on one ribbon also makes the process of labelling products much easier.
To speed up the printing process, it is worth taking a moment to properly prepare the file for printing. Thus, you will save your time and get the final product faster. Remember that the completion date is counted from the moment of accepting the graphic files – well-prepared files will significantly speed up our work.
The most important elements
of file preparation
for flexographic printing
FILE Format
Color
Fonts
bleeds
Punch
Resolution
masks
1. .AI .PDF file format
The specificity of flexographic printing requires us to interfere with the graphic file and rework its layers, e.g. when correcting traps or masks. Therefore, we need an open file with saved layers with which we can easily work. The prepared file should be saved in an open format, such as:
-
.AI -
.PDF
Ai. Files prepared in Adobe Illustrator, ver. CC 2019. with saved layers and embedded photos in the file.
PDF. Files prepared in other programs. Saved to PDF version 5.0 or higher with preserved layers and the possibility of editing.
Digital printing - preparing files for digital printing is not that complicated and does not require as much attention as flexographic printing, but to speed up the printing process, prepare files in .Ai or .PDF format as well.
Note! If you do not have a file in the above-mentioned formats, please send it to us in the version you have. We will perform the order from the file sent, but this may affect the order completion date.
2. Colors - CMYK
Color is one of the most important issues in printing. Before printing, most of the designs are visible only on the computer screen. Depending on the quality of hardware, your design may differ from monitor to monitor. The problem of transferring the colors visible on the screen to the paper results from one fundamental difference – the screen is black, we light up its space by combining the basic colors of red (R), green (G) and blue (B). Thus, we get the desired color, the more light, the brighter the color. At the maximum moment, we will get pure white on the screen. However, it is the opposite in printing, where we start with a white sheet of paper, which we print with the basic colors Cyan (C), Magenta (M), Yellow (Y) and Black (K). The more paint, the darker the color.
All colors in CMYK
Remember to work in the CMYK color space. This will guarantee a much greater color reproduction of what you see on the screen. This does not guarantee full screen reproduction, but it will certainly be closer to the truth than with RGB designs.
CMYK
RGB
Note! This is the difference between automatically converting RGB files to CMYK. For technological reasons, it is not possible to fully reflect the RGB color scheme in print.
Digital printing - regardless of whether we print in digital or flexographic technology, the design will reproduce the computer screen if it is prepared in CMYK colors.
3. Fonts
Label designs contain a lot of descriptions and texts. They are often written with different typefaces, divided in a special way, maintaining appropriate distances and divisions between the characters. Everything looks fine while working on computer, opening a file elsewhere can make the file look completely different.
convert fonts to curves
To avoid such a problem – convert all fonts to curves. Thus, the written font will be saved as a geometric object that will be equally visible on other computers.
single color text
Using CMYK with small text can make the text unreadable by shifting the color layers that are applied. To avoid this problem, the text should consist of one color.
minimum line thickness
To make the texts and the applied graphics clear, do not use lines thinner than:
0,08 mm of one color
0,5 mm in folded color
0,15 mm of one color counter
0,8 mm in folded color counter
Digital printing - always change fonts to curves, no matter if you print digitally or in flexographic technology. Digital printing technology allows printing very thin lines and very small fonts, but it is recommended that they should not be smaller than 4 points.
Note! Note that once the text is converted to curves, it cannot be edited.
4. Bleeds
2 mm minimum on each side
Bleeds are the area of design that will be cut off by the die. However, in the place that will be cut there must be graphics so that even after a slight shift, the image still looks aesthetically and has graphics printed on it.
Digital printing - in this case, the technology does not matter, no matter if we print digitally or flexographically - bleeds are always required. When cutting labels, a part of the print will always be cut off by the punch knives.
Note! Remember that the bleeds are not part of the image composition. The final file, after confection, will have a net format and the bleeds will be cut off.
5. Punch
put the die line on the design
Label designs often come in different shapes and dimensions. Thanks to technology, we are able to cut every shape in the material, but we need to know its relation to the label. Therefore, always place the die on the graphic on a separate layer or on an additional color.
Digital printing - do not apply the die as a graphic in the digital printing project. Mark it as a spot color or mark it on a separate layer. Also remember to centre the file in the work area.
6. Photo resolution
Photo resolution - 300 dpi
Resolution is nothing more than the density of the printed colored dots on the material. In order for the image to be clear and sharp, the dots must be densely printed. Projects prepared for printing should be saved in a resolution of min. 300 dpi. Otherwise, the printed image may be blurry and pixelated.
300 DPI
72 DPI
Move the slider to the right or left to see the real difference between the DPI resolution of the file. On the right side there is a file prepared for printing at a resolution of 300 dpi, on the left side there is a low resolution file not suitable for printing.
Digital printing - the resolution in printing should always be kept at 300 dpi.
Note! The example shown is a mapping of a low resolution file in print. Low resolution files on the screen don’t have to look like this. The difference may be imperceptible on the computer, but we can be disappointed after printing.
7. Masks and spot color
When preparing files for printing, we often find the so-called masks and spot color. We create them to mark places in the graphics that we want to additionally cover with varnish or a different color of paint.
It is very important when we print on non-standard bases of other colors, e.g. silver or transparent. The applied paints may finally look different than the design on the computer, so we use a white sheet, i.e. white paint line up. We can use such an underprint as a whole, but more often we do it selectively to show the values of the raw material itself. This is the case with silver Rainbow foils, where after a single print we get a shimmering color, and a standard print in the place where the white sheet is placed.
How to properly prepare a spot color mask.
- Set „spot color” in the program. Name it White1.
Tools> Palette Editor> from the drop-down list select: User Palettes> Custom Spot Colors> Add Color> enter color in CMYK> click Add to Palette
Window> Samples> New sample> enter the name White1> Change Color Type to Spot Color> enter CMYK values
Window> Color> Samples> New color sample> enter the name White1> Change Color Type to Spot Color> enter CMYK values
2. Then, use the „spot color” to fill all the elements to be printed. Give them the attribute „Darken/Multiply”.
3. We avoid setting the „Fill overprint” attribute, because unfortunately pdf does not display it properly, and some rippers remove it by rule.
select the object> right-click> Overprint Fill
Window> Appearance> Opacity> Darken/Multiply
Window> Appearance> Opacity> Darken/Multiply
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