How Durable Are Watermarks? Compression & Processing Resistance Test Report

'Won't the watermark disappear if the image is processed?' This is the most common question when considering watermarks. In this article, we subjected Adobe TrustMark watermarks used by truvis to various real-world image processing operations — JPEG compression, resizing, screenshots, SNS posting, and cropping — to verify how well watermarks can be detected afterward.

Test Conditions

The experiments were conducted under these conditions: - Tool: truvis (Adobe TrustMark technology) - Test image: 1920×1280 pixel photograph (PNG format) - Embedded payload: 8-character ASCII string - Verification: After each processing, watermark detection was attempted using truvis's decode function - Criteria: If the embedded payload was correctly extracted, it was marked as 'Detection Successful'

Test Results

JPEG Compression

Watermark durability was tested by progressively lowering JPEG quality: - Quality 95: Detection Successful - Quality 80: Detection Successful - Quality 60: Detection Successful - Quality 40: Detection Successful (partial payload errors may occur) - Quality 20: Detection Failed In practice, stable detection is possible at JPEG quality 60 and above. Quality 40 is approximately the threshold.

Resizing (Downscaling)

The image was progressively downscaled for testing: - 75% reduction (1440×960): Detection Successful - 50% reduction (960×640): Detection Successful - 25% reduction (480×320): Detection Successful (accuracy may decrease) - 10% reduction (192×128): Detection Failed Detection is possible down to approximately 25% of the original size. However, detection accuracy drops significantly below 256×256 pixels.

Screenshots

The image was displayed in a browser and screenshots were taken for testing: - Screenshot at 100% display: Detection Successful - Screenshot at enlarged display: Detection Successful - Screenshot at reduced display: Detection Successful (fails if display size is too small) Watermarks remain detectable after screenshots when display resolution is sufficient.

SNS Posting

Images were posted to major social networks and downloaded for watermark detection: - Twitter/X: Detection Successful (with JPEG recompression) - Instagram: Detection Successful (with significant recompression) - LINE: Detection Successful (when sent as 'Original Quality') - Facebook: Detection Successful (with JPEG recompression) Watermarks survive standard processing by major SNS platforms. However, LINE's normal quality (auto-compression) may prevent detection.

Cropping

Portions of the image were cropped for testing: - 10% crop (slight edge trimming): Detection Successful - 30% crop (center portion extracted): Detection Successful (accuracy may decrease) - 50%+ crop: Detection Failed Detection is possible when most of the image remains, but becomes difficult when more than half is cropped.

Results Summary

Watermark Durability Test Results

TrustMark watermarks demonstrate durability against most common image processing operations. [High Durability] JPEG compression (quality 60+), resizing (25%+), screenshots, major SNS posting [Limitations] Extremely low JPEG quality (below 20), drastic downscaling (below 10%), cropping more than 50% Deep learning-based TrustMark technology achieves overwhelmingly higher durability compared to traditional DCT-based watermarking.

Practical Recommendations

Based on our test results, here are recommendations to maximize watermark effectiveness: - Embed in high-resolution images — 256×256 pixels minimum recommended. Larger images provide higher durability. - Store originals in PNG format — Lossless PNG compression prevents watermark degradation. - Embed before SNS posting — It's important to embed watermarks before posting, accounting for recompression during upload. - Keep watermarked images — Store watermarked images as master files for use as evidence of ownership.

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