What causes dot gain in printing?

31 Jan 2023
Dot Gain

Label and packaging printers are under pressure to deliver speed, volume and quality with every run, and under tighter lead times than ever before.

There is an increasing number of plates to spin in order to achieve print perfection and under tighter margins and heightened focus on sustainability, the result is that no printer can afford costly and wasteful reprints due to print imperfections.

One common source of print defect is dot gain – but what is it, and what can cause it?

 

What is dot gain?

The flexographic printing process creates graphic blocks, colour and text using countless tiny dots of colour across the substrate. This gives designs sharply defined detail, alongside consistency, vibrancy and an effective way to gradient colour. To the human eye, these dots or halftones are imperceptible from standard visual ranges, appearing as solid colour. They combine to create an image or a printed colour in Cyan, Magenta, Yellow & Black (CMYK) process colours or spot colours.

Dot gain is a phenomenon that occurs when printed dots of ink appear larger and less defined than their intended size – and can prove a major problem for printers.

A number of problems can arise from dot gain, such as fuzzy, blurry or poorly defined images, or text appearing darker and bolder than intended with the appearance of smudging. The upshot is that if dot gain is not controlled or counteracted during prepress, the quality of print is significantly harmed. Over the long print runs required in today’s volume focused market, the results can be disastrous for packaging and label printers.

 

What causes dot gain?

With escalating demands from consumers and brands alike, label and packaging printing can be a very complex process, with many ‘moving parts’ in synchronicity. A number of key factors can contribute to dot gain, including the properties of the ink and substrate being used, the design and layout of the printing press, and the experience of the operator.

One of the most significant contributing factors is the printing process itself, with offset printing and flexographic printing being particularly prone to dot gain due to the nature of ink transfer.

Many different factors can cause dot gain, but common issues for printers to remain aware of include:

  • Excessive pressure on print cylinder impacting consistency
  • Ink viscosity – too low, and the ink is more likely to spread across the substrate
  • Incorrect thickness of flexo plates affecting pressure and precision
  • Press machinery wear and tear
  • Dots on the printing sleeve entering the anilox

 

How can dot gain be avoided?

Often, dot gain is unavoidable and can only be controlled, rather than eliminated.

The ink transfer process must be controlled carefully and where dot gain is expected, counteracted and compensated for in prepress. This can be achieved through a combination of proper press setup, operator training, and the use of compensating tools and techniques.

Colour management software can be used to adjust the dot size and placement during the printing process, through creating a custom ICC (International Color Consortium) profile that takes into account the specific characteristics of the press and substrate being used and adjusts dot profiles accordingly.

Another approach to compensating for dot gain is ‘trapping’. This is where dots on the edge of colour boundaries are repositioned to prevent edges appearing blurred or fuzzy, and keeping lines looking solid and crisp.  Another technique called screening can also be used to adjust the size and placement of dots to minimize dot gain.

Of course, one of the most effective ways for printers to reduce the risk and impact of dot gain is by partnering with an experience reprographics partners such as Creation. A team, experienced in all things packaging and label prepress, can provide expert guidance on optimising the printing process and minimising dot gain. Partnering with a business like Creation brings a vast spectrum of advantages over handling prepress entirely in-house.

The key is unparalleled knowledge of press setup and origination, as well as depth of experience in inks and their behaviours. As a specialist in packaging reprographics, Creation offers a full suite of prepress and colour management services, designed to help printers accomplish more with their print operations and take away significant pain points.

Could Creation be the key to boosting your label and packaging print operations? To find out more about Creation and its expertise, click here to contact our team today.

Questions?
Contact us on +44 (0) 1604 906000  or info@creation-repro.com
and we’ll be happy to help