The Role of an Underbase
Introduction to Underbase Printing
Importance in Color Vibrancy
- The underbase serves as a foundation layer in screen printing, particularly when printing on darker garments. Its primary function is to ensure that the main colors of the design appear vibrant and true to their intended hue. Without an underbase, the garment’s color can influence or mute the printed inks, leading to a less accurate representation of the design. For instance, printing a yellow ink directly onto a dark blue shirt might result in a greenish hue due to color mixing. By applying a white underbase first, the yellow ink is printed on a neutral surface, allowing it to display as intended.
Minimizing Fiber Visibility
- Certain garment fabrics can result in fibers protruding through the ink, creating a rough texture. An underbase smoothens this surface and reduces fibrillation.
Tackling Dye Migration with Blocker Inks
- Garments, especially those made of polyester or blends, can exhibit dye migration. The underbase acts as a barrier, preserving the print colors.
Common Mistakes and Best Practices
Many screen printers overlook the nuances of background color or the underbase. This article compiles essential constants to help you identify potential improvements in your process.
Choking the Underbase Film
To avoid visible underbases, especially when the top colors aren’t perfectly aligned, consider choking the underbase film, i.e., slightly reducing its size relative to the top colors.
Importance of Mesh Tension
- Mesh with inadequate tension won’t produce a sharp underbase. It’s crucial to ensure that all screens have appropriate tension, as per there suppliers mesh chart.
Selecting the Right Mesh Count
- Balancing Opacity with Detail: Typically, an underbase uses a mesh count ranging from 43 – 61 threads per centimeter (110-160 threads per inch). This count, lower than that for top colors, guarantees required opacity while retaining design intricacy.
- Ease of Ink Release: Pairing the correct mesh count with optimal EOM ensures a seamless release of the underbase ink from the mesh.
Delving into Emulsion
Understanding Emulsion Over Mesh (EOM)
- The right EOM is vital for the underbase, ensuring adequate emulsion thickness for the right ink deposit. This achieves a vibrant underbase without sacrificing detail.
Ensuring Proper Coating Techniques
- Achieving Proper EOM: Effective coating techniques are essential to attain the desired EOM. Properly coated screens ensure the right ink deposit—crucial for an underbase—while preserving design clarity.
- Ink Consistency: Proper coating guarantees a consistent ink deposit across the design, laying the foundation for a perfect final print.
Choosing and Managing Inks
Picking the Perfect White Ink
The underbase often utilizes white ink with robust opacity. However, if the top colors are highly opaque, a semi-opaque white ink might be preferable. Selecting the right ink to minimize fiber visibility and ensure smooth overprinting is essential.
Adjustments for Plastisol Inks in Cooler Climates
White plastisol inks, especially, react differently in colder conditions, becoming thick and challenging to print. It’s advisable to warm them by thorough mixing.
Screen Printing Techniques Perfected
Nailing the Offcontact
Appropriate off-contact is critical for impeccable printing, ensuring ink stays atop the garment. The required off-contact varies depending on the garment, but the aim is always that the screen mesh is clearing well.
Mastering the Squeegee Technique
- Type and Durometer: The right squeegee is pivotal. Typically, a softer squeegee, usually within the 60-75 durometer range, is preferred since it deposits more ink. However, the exact durometer might vary depending on the desired ink deposit and the specifics of the print job.
- Edge and Shape: The squeegee’s edge, whether sharp or rounded, profoundly impacts the ink deposit. A sharp edge tends to lay down a thinner ink layer, while a rounded one gives a thicker deposit.
- Setting Angle: The angle at which the squeegee is set plays a crucial role in the printing process, directly influencing the color application and defining the amount of ink deposited onto the garment
- Influence on Color: The combination of squeegee type, durometer, edge, and angle all play a role in determining the vibrancy and accuracy of the printed color. Adjusting these parameters can help printers achieve the desired color application and finish.
Flashing the Ink Right
Flashing ensures partial ink setting, so there is no “pickup” from the top colors screens. However, over-flashing any color can cause more problems than benefits. Specifically, over-flashing with water-based inks might pose washability issues. Hence, preheat your printing pallets and adjust the flashing time as needed.
Advanced Underbase Techniques
Introduction to Discharge Underbase
For reactively dyed garments, a discharge underbase can prove beneficial, removing garment dye in the printed region, leading to brighter prints on dark fabrics.
Adapting to Environmental Variabilities
Both humidity and ambient temperature influence ink behavior, drying times, and more. Adjust techniques based on these Screen Print variables.
Upholding Printing Standards
- Ink Management: Periodically check the condition of your inks. Be mindful that plastisol inks, when warm, may have diminished opacity. On the other hand, water-based inks are prone to drying out. To counteract this, keep them humidified using a water spray.
- Equipment Monitoring: Regularly inspect your squeegees for wear and tear. It’s essential to maintain consistent screen tension to ensure high-quality prints.
- Testing Protocols: Before embarking on a full print run, always conduct test prints to ascertain print quality. Given that thicker ink deposits may necessitate longer curing durations, adjust your curing times accordingly.
- Final Garment Quality Control: After the printing process, always perform wash tests on the final garments. This step ensures the durability and longevity of the print in real-world conditions.
Emerging Techniques and Trends in Underbase Printing
- Digital Hybrid Printing: Merging traditional screen printing with digital methods, especially for underbase applications, enhances design complexity without the need for multiple screen setups.
- Advanced Ink Formulations: New eco-friendly, stretch-resistant, and fabric-specific inks alter underbase printing approaches.
- Underbase Modifiers: Modifiers that adjust ink properties, like viscosity, provide screen printers with enhanced control over print jobs.
- 3D Screen Printing (PUFF): Achieve tactile designs with a raised effect using specialized underbase techniques.
- Specialized Underbases: Tailored underbases for technical fabrics in sportswear and fashion ensure optimum adhesion and vibrancy.
- UV-LED Curing: While providing energy efficiency and reduced heat, UV-LED lights demand a different underbase interaction during the curing phase.
- Water-Based Underbases: The push for eco-friendly solutions brings water-based underbases into focus, necessitating distinct handling from traditional plastisol ones.
- Print Software Advancements: Modern software can now predict color and fabric interactions, aiding in design decisions.
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