In the flexographic printing world, paying attention to the tiniest of details can make the biggest of differences. One small detail that requires attention is dot profiles ( or shapes).
It seems simple enough to overlook, but the experienced flexo printing pro knows that the implications behind using different image carrier dot profiles can drastically affect the quality of the finished prints.
Why Do Flexo Dot Profiles Matter?
There can be two different dot profiles – flat or round – which will have an impact on the final printed product.
The choice of dot profile is based on many factors including:
- Ink characteristics
- Desired color density
4 Key Factors in Deciding What Dot Profile Is Best For Your Print:
When talking to your image carrier supplier, here are some considerations to discuss so that they can help decide what’s best for you:
Roundtop dots will produce varying final print results depending on the printing pressure. Without knowing what’s best for your print, this can lead to significant dot deformation or unpredictable dot gain.
Roundtop dots have the ability to print a finer, smaller dot due to the rounded contact point and are often used for highlight or detail areas.
A flat-top dot has a defined surface which leads to less variability in dot gain based on pressure and increased benefits for solid, dense ink areas and reverse printing projects -- especially for printing jobs involving flexible or corrugated substrates.
They also allow more ink to be transferred to the substrate from the image carrier. The steep dot shoulders allow for greater image carrier floor depth - even when the dots are close to each other in dense printing areas.
2. Printing Results
Roundtop dots are highly sensitive to change under pressure, which can cause problems in certain print jobs. As the printing pressure is increased, the color density can change rapidly.
Flat top dots are less impacted by pressure on the press, so a higher degree of image consistency can be achieved throughout the press run.
The flat-top dots manage to maintain a far crisper edge and a better-defined printing surface. They are known for providing an optimal dot structure, resulting in improved color control for increased vibrancy.
3. Effect on Image Carrier Stress
Flat top dots are generally considered to be the more durable dot, which can lead to a significantly longer image carrier life than rounded dots.
4. Cost Considerations
Flat top dot image carriers yield longer press life and more consistent prints, which can increase profitability.
Where Dot Profile Is Headed
Ever-improving dot technology will enable flexo printers to expand their printing capabilities into more products that are currently performed by offset or gravure printers. Items such as high-end labels, cartons, and flexible packaging can be printed using the flexographic process.
With a solid understanding of the key aspects of the flexographic printing process such as ink choice, dot profile, image carrier, and ink transfer – printers have the opportunity to produce higher quality images now more than ever before.
Editor's Notes: This blog post was originally published in September 2018 and updated in March 2022 to reflect recent information for our readers.