Navigating the world of screen printing can be complicated, especially when it comes to reclaiming screens that have not been exposed correctly.
The main challenge
A substance known as sensitizer, which, when not properly cross-linked due to underexposure, results in a stubborn emulsion layer that’s tough to remove.
The degree of exposure – how the screen was exposed and the intensity of exposure – plays a key role in whether screens are easy or difficult to reclaim. If a screen is not adequately exposed, the sensitizer remains partially uncross-linked, making the emulsion layer overly sensitive to light and chemicals.
Screen cleaning products are another important factor to consider. In the past, potent solvents like mineral spirits or paint thinners were commonly used. However, because these cleaners contained high levels of Volatile Organic Compounds (VOCs), they’ve been largely replaced by cleaners with low VOCs. Despite this, many print workshops globally still use harsh solvents that may interfere with the screen reclaiming process.
One thing to be aware of is that underexposed emulsion can be partially washed away during the development phase. This can be due to a weak lamp or not enough exposure time. A common mistake is to underexpose screens deliberately to capture finer detail. While this might result in attractive tonal variations, it can cause much of the emulsion to wash off during development. This can lead to screens that are fragile and prone to breaking down after only a few prints.
This article asserts that the secret to producing durable screens and facilitating easy emulsion reclaiming lies in thorough and complete exposure. While it may be tempting to use quick or inexpensive exposure methods, these shortcuts can compromise the durability of your screens.
Modern cleaning products are less harmful to workers and the environment and have less of an impact on emulsion than older, solvent-based products. However, the type of emulsion used can still influence the screen reclaiming process.
Lastly, effective communication within the print shop is key. After all, underexposed screens can lead to higher costs and reduced efficiency. As a result, it’s vital to understand and implement correct screen exposure practices.
Questions & Answer
What is reclaiming screens screen printing?
Reclaiming screens in screen printing refers to the process of removing old ink and emulsion from the screen and preparing it for the next print job. Special screen printing chemicals are used to clean and prime the mesh. It is essential to reclaim screens to ensure optimal results when reusing them.
Can I reuse screens for screen printing?
Yes, screens can be reused for screen printing. To maximize their lifespan, it’s essential to clean and reclaim them properly. Rough handling can reduce their longevity, but inadequate cleaning can lead to issues like poor emulsion adhesion, pinholes, and blurred prints. Ensure you follow best practices to maintain the quality of your screens.
