This section covers the principles to follow to create a file that's ready for printing with Packly. Following them carefully helps you avoid issues during the file check.

One important premise. The exact values of certain parameters (bleed, safe area, colour mode) vary depending on the product and material: a box in corrugated cardboard, one in solid board and a tissue paper pack don't share the same thresholds. Below you'll find the principles common to all Packly guidelines and the reasoning behind each one; for the exact value that applies to your product, download the specific guide in the section at the bottom of the page.

Dieline

The dieline you download from Packly must remain in the artwork file with its original colours: it must never be moved, deleted or modified, and no unrequested lines should be added. The dieline's lines have a colour linked to a precise technical meaning, for example green for bleed, blue for cut, a dedicated colour for crease, which our system reads automatically during checking. Altering even a single line risks invalidating the file.

Bleed

Bleed is the part of the artwork that must extend beyond the cut line: without it, a minor misalignment in production could leave a visible white line along the edge of the product. The principle is the same for all Packly products, but the exact measurement isn't the same everywhere - it varies depending on the product and material. The correct value is always given in the downloadable guide for your product.

Minimum distances (safe area)

In addition to bleed, a safe area must be respected between important graphic elements (text, logos, details) and the cut and/or crease lines, to avoid them being cut off or folded by mistake. Here too, the measurement varies depending on the product and material: you'll find it in the corresponding downloadable guide. Avoid, especially in areas close to cuts and folds, frames, borders, lines or graphic elements that require precise alignment.

Layers

The dieline and the artwork must be on two separate layers. Remove from the file any layers that aren't visible or that contain elements you don't want printed. If your project involves additional processes - a special finish, a custom cut-out - you can add a layer for each and use the dedicated spot colour. For full technical guidance on setting up these spot colours and the minimum distances to respect, see the dedicated articles Special finishes: what they are and Can I add windows or cut-outs to my box?

Lines

Keep all lines in the artwork file at a minimum thickness of 0.3pt (0.1mm): thinner lines risk not being reproduced accurately in print. The exception is lines used to indicate special processes (finishes, custom cuts or perforations), which follow their own, slightly higher minimum thicknesses - the detail is in the dedicated guide for that process.

Text

Text must be larger than 3pt (4px): below this threshold it risks being illegible or not reproducing correctly in print. Where printing is in CMYK, for black text it's best to use K=100% instead of a colour combination, to get a crisper, sharper black and avoid smudging caused by misregistration between the colour channels.

Image resolution

Images must have a resolution between 200 and 300ppi; bitmaps can go up to a maximum of 600ppi. Below the minimum threshold, the image loses definition in print; beyond the maximum indicated for bitmaps, there's no visible benefit, just a heavier file.

Colours

This is where the difference between products is most significant, so read it carefully. For most Packly products, printing is done in CMYK four-colour process: if the file contains Pantone® colours or RGB images, these are converted automatically, but it's best to convert them to CMYK yourself before uploading the file, to keep control over the final colour rendering - colours that aren't yet in CMYK also aren't displayed correctly in the 3D preview. Some products, such as tissue paper, don't follow this rule: printing is done with a single colour selectable from a dedicated palette, not in CMYK, and only positive printing is allowed (graphic elements and text printed in the chosen colour on the paper's background colour); excessive coverage of the paper with the print colour is not permitted. Also bear in mind that the colour of the substrate (white or black paper) cannot be used as one of the artwork's colours: every element must be printed at full coverage with the selected ink. Always check your product's guide to see which rule applies. The colour displayed on screen is not a reliable reference for assessing the print result. If your project involves printing on both the outside and the inside of the box, colour rendering and file preparation methods change depending on the material: you'll find how it works and technical advice in the dedicated article Outside and inside printing: how it works and which materials it's available on.

Rich black

For backgrounds and large black elements, in products printed in CMYK the recommended combination is C=40% M=30% Y=0% K=100%: a solid black at K=100% alone tends to be less intense and even in print than this combination. This tip applies only to products printed in four-colour process, not to single-colour printed products.

Grey background

To achieve a neutral grey shade, in CMYK products it's best to use only the black channel (for example C=0% M=0% Y=0% K=50%), avoiding composing the grey from other channels: this prevents unwanted colour casts caused by minor print misregistration between the channels. Here too, the tip applies only to CMYK-printed products.

Saving the file

The dieline downloaded from Packly must remain in the file with its original colours. In every case, save the file using the Adobe® PDF "High Quality Print" preset: this setting ensures correct handling of resolution, colour and transparencies during printing.

Before uploading the file: the final check

Before exporting and uploading the file, double-check these points: they are the most frequent cause of rejection or delay during checking:

  • the dieline is still the original one, not modified, moved or rotated;
  • artwork and dieline are on separate layers (with additional layers for any special processes);
  • bleed and safe area respect the values given in the specific guide for your product - not those of another product;
  • images are between 200 and 300 ppi;
  • the file is in the correct colour mode for your product (CMYK, or the single colour provided for products such as tissue paper).

Once the file is uploaded, our prepress team checks its printability before giving the go-ahead for production. You'll find the details of what's checked at this stage - and what happens if the file isn't print-ready - in the article Does Packly check the graphic files before printing?

Complete guides to download

For the complete technical detail for your product, download the corresponding guide.

Packly printing file guidelines

Packly Bag-in-Box printing file guidelines

Packly Bottle Boxes printing file guidelines

Packly Tissue paper printing file guidelines

Packly Standard Products printing file guidelines

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