A Complete Guide to DTF Film Quality Testing

In the DTF (Direct-to-Film) printing industry, the quality of the DTF film is crucial as it serves as the medium that carries the print design and transfers it onto textile fabrics. The quality of the film directly affects the final product. With the rapid development of DTF printing technology, a wide range of DTF films are available in the market, but their quality varies significantly. So, how do you choose the right transfer film for your DTF printing business? This article will analyze common issues in DTF printing and guide how to evaluate the quality of DTF films, offering a reference to help you select the most suitable product.

Common Problems and Causes in DTF Printing

During the DTF printing process, the following common problems may occur if the DTF transfer film quality is poor:

 

Ink Flow and Ink Bleeding Issues

A common issue when printing with high ink volumes is ink flow or bleeding, where white ink and color inks mix, leading to imprecise printing. One reason for this is the poor ink-holding capacity of the DTF film; another reason is the uneven coating of the DTF film, which results in varying ink absorption across different areas, affecting the stability of the ink.

 

Water Staining and Hot Melt Powder Residue on Image Edges

During printing, water may spread along the image's contours, creating water stains, which can lead to hot melt powder residue on the edges of the design after powder shaking. After transfer, this can result in glued edges that affect the clarity and appearance of the image. The root cause of this problem is the poor water absorption capacity of the DTF film, which fails to effectively control the spread of water, leading to blurred image edges. This issue is especially noticeable when printing fine text or intricate lines (e.g., wash labels).

 

Uneven Color and Noise Issues After Transfer

Another common problem is the uneven color or noticeable noise in the transferred image. This is typically caused by uneven coating of the DTF film or incompatibility between the DTF ink and the film material. Uneven coating results in an irregular ink distribution on the film surface, affecting color uniformity. Poor ink-film compatibility may also cause undesirable color performance, such as color variations or visible speckles.

 

Hanrun Paper DTF Film Quality Control Process

The quality control process for DTF films is essential for ensuring their quality. A comprehensive quality control process evaluates various performance indicators of the DTF film, helping to select products that meet high standards. The following is a detailed analysis of Hanrun Paper's DTF film quality control process:

1. Appearance Inspection  

The appearance inspection is an important first step in evaluating DTF film quality. Any defects can affect the final print results. 

Coating Uniformity: The film's surface should be free of scratches, dirt, or residue. The coating should be uniformly applied without bubbles, ensuring full coverage without gaps. 
Film Thickness Measurement: The thickness of the film should meet the specified standards, with a ±2 deviation range. 

Edge Inspection: The edges of the film should be neat, without any mechanical damage such as wavy patterns, ensuring ease of operation and smooth printing in production.
Release strength: Scrape the DTF film coating with a fingernail without exposing the PET-based film.

2. Print Quality Testing  

Print quality is a crucial step in evaluating the DTF film's overall quality, impacting the clarity, color vibrancy, and detail of the printed design. 
Ink Compatibility: Test DTF film for compatibility with EVO and PRO inks and a variety of printing equipment to ensure uniform ink absorption and color accuracy.
High-Precision Print Test: Under platform heating conditions, 8 PASS high-precision testing of printing effects is used to ensure that Pantone color blocks and gradient color blocks are printed without obvious white spots, even color distribution, and no ink flow or aggregation.
Print Noise Check: Test the printed image to ensure no noticeable noise spots, or the point noise size is less than 0.1mm.
Water Edge Test: Check if water edge issues occur in the print area. 

3. Powder Shaking Quality Test  

The powder shaking performance of the DTF film directly affects the transfer results, especially in high-quality DTF T-shirt printing applications.
High-Temperature Deformation Resistance: The DTF film should remain stable at high temperatures, withstanding drying temperatures up to 130°C and press temperatures up to 160°C. The film should not be yellow or wrinkled under high temperatures.
Clean Powder Shaking: Non-printed areas should not be left over hot melt powder after the powder shaking process, ensuring the transfer design's edges are clear.
White Spot and Snowflake Spot: Conduct a powder shaking test at 130°C for 15 seconds to ensure no white or snowflake spots, guaranteeing a flawless final print.

4. Heat Transfer Peeling Test  

The ease of peeling the film after heat transfer is crucial to the success of the transfer process. 
Peel Time and Quality: After pressing at 150°C, the design on the film should peel off cleanly and quickly, ensuring the integrity of the design. Non-printed areas should not lose coating. Ensure it applies to common fabrics such as cotton, linen, polyester, and chemical fiber. 
Oil and Water Return Test: After resting at room temperature for 2 hours, conduct an oil and water return test to ensure no oil or water exudes from the printed area. 
Washability Test: Perform 1-5 wash tests on the printed sample to check for fading or design peeling, ensuring the DTF print stability during actual use.

Selecting Quality for Outstanding Printing

As a pioneer in DTF digital printing technology, Hanrun Paper has been heavily invested in the research and development of DTF PET films since 2020. In April 2021, the company successfully developed and patented the DTF film (Patent No. ZL202110519575.4) and began large-scale production. In terms of material selection, we strictly follow environmental protection principles, with all materials meeting OEKO standards to ensure no negative environmental impact when our products are used.

Hanrun Paper has established a comprehensive quality inspection and shipping process for DTF films, carefully controlling each step. We not only provide high-quality DTF films but also offer full services, including free sample testing and technical consulting, ensuring customers get the best experience. With superior quality and performance, Hanrun Paper's DTF films have earned the trust and high praise of a wide range of customers.

If you are looking for a high-quality DTF film product, feel free to contact us below for sample testing.