Dot gain refers to the increase in size experienced by the dots in the printed image compared to their original size on the printing plate. Having it under control ensures high-quality reproduction, preventing loss of fine detail and ensuring colors are bright and saturated, reducing registration problems and color deviations in print, which can save time and production costs by minimizing the need for additional adjustments and corrections.
It is important to note that dot gain can vary depending on the type of substrate used, so controlling it properly can help ensure consistent print quality across different materials and substrates.
Not having dot gain controlled can affect the quality and sharpness of the printed image, as fine details can be lost, and colors appear less bright or saturated. The factors that alter it can be in the absorption of the ink by the substrate, excess or lack of pressure of the photopolymer during the printing process, they can cause an inadequate transfer of the ink to the printing surface.
To control it, the following techniques can be used:
• Proper selection of photopolymers: It is important to choose the correct photopolymer that has the ability to accurately reproduce dots without increasing their size in print.
• Temperature and humidity control: It is important to maintain a constant temperature and humidity in the print area to avoid changes in the expansion and contraction of the photopolymer, which can affect dot gain.
• Printing pressure adjustment: It is necessary to adjust the printing pressure appropriately to avoid deformation of the photopolymer and dot gain.
• Selection of suitable inks: The selection of suitable inks is also important to control dot gain. It is recommended to use inks with a suitable viscosity and good absorption capacity.
• Proper selection of anilox cylinders: Selection of anilox cylinders with the proper cell volume is important to control the amount of ink that is deposited on the substrate. Choosing the right anilox cylinders also helps to avoid scoring.
• Print speed control: It is important to control the print speed to avoid deformation of the photopolymer and dot gain.
If by doing all of the above, you can’t control the gain, we recommend making a compensation curve. Using this tool, a series of print tests are performed using different curve settings to determine the amount of correction needed on the printing plate to achieve the desired printed image.
This curve is specific for each combination of ink, substrate and printing plate used and must be adjusted according to the specific characteristics of each of them. The dot gain compensation curve can be created using a densitometer or spectrophotometer, which measure the amount of ink that is deposited on the substrate and the reflectance of the printed surface.
At Grafiflex SRL, we are aware of what it means to be a differential within the competition, we understand the need to be at the forefront and offer flexographic solutions to a trade as demanding as ours. Controlling dot gain ensures high print quality prints and accurate reproduction of the original image, without wasting time and money.
Would you like us to help you control the dot gain in your process? Write to us, let’s achieve together the impressions you want so much.