When you submit fingerprints to ATF eForms, your EFT file contains specific record types defined by the ANSI/NIST standard. Understanding the difference between Type-4 and Type-14 records helps explain why some conversion services work better than others—and why proper EFT formatting matters for approval.
In This Guide
Introduction to NIST Fingerprint Records
The ANSI/NIST-ITL standard (American National Standards Institute / National Institute of Standards and Technology - Information Technology Laboratory) defines how fingerprint data is encoded in EFT files. The current version used by ATF is based on NIST Special Publication 500-290 and the EBTS 8.1.0 (Electronic Biometric Transmission Specification).
An EFT file contains multiple "records" or "types":
- Type-1: Transaction header (required)
- Type-2: Demographics/user-defined data
- Type-4: Legacy grayscale fingerprint images
- Type-14: Modern variable-resolution fingerprints
For ATF submissions, the critical choice is between Type-4 and Type-14 for the actual fingerprint images.
What is Type-4? (Legacy Format)
Type-4 records were defined in the original 1986 ANSI/NIST standard and were the workhorse of FBI fingerprint databases for decades.
Type-4 Characteristics
- Fixed 500 PPI resolution - No flexibility in image resolution
- 8-bit grayscale - 256 levels of gray
- Binary encoding - Raw pixel data, minimal compression
- Designed for rolled prints - Originally for single-finger rolled impressions
- Limited metadata - Basic fields only, no segmentation data
- Large file sizes - Uncompressed or lightly compressed images
When Type-4 Was Used
Type-4 records dominated from 1986 through the early 2000s. They're still supported for backwards compatibility with legacy FBI systems, but modern electronic submissions have moved to Type-14.
Type-4 Limitation: Type-4 cannot encode slap images (multiple fingers in one image) with proper segmentation. This is why ATF eForms rejects Type-4-only submissions—the system needs to identify individual fingers within slap images.
What is Type-14? (Modern Format)
Type-14 records were introduced to address Type-4's limitations. They're now the standard for electronic fingerprint submissions, including ATF eForms.
Type-14 Characteristics
- Variable resolution - 500 PPI standard, but supports higher resolutions
- WSQ compression - FBI's wavelet-based compression algorithm
- Slap image support - Multiple fingers in one image with segmentation
- Rich metadata - Extensive fields for quality, coordinates, and processing info
- Segmentation coordinates - Identifies where each finger is located in slap images
- Smaller file sizes - WSQ achieves 15:1 compression with minimal quality loss
Critical Type-14 Fields for ATF
ATF's EBTS validation specifically checks for these Type-14 fields:
| Field | Name | Purpose |
|---|---|---|
14.013 |
FGP (Finger Position) | Identifies which finger(s): 13=Right Four, 14=Left Four, 15=Thumbs |
14.021 |
SEG (Segmentation) | Number of fingers in the slap image |
14.023 |
SQS (Segmentation Quality) | Quality score for segmentation accuracy |
14.024 |
ASEG (Alternate Segmentation) | Bounding box coordinates for each finger |
14.999 |
DATA (Image Data) | WSQ-compressed fingerprint image |
Technical Comparison Table
| Feature | Type-4 | Type-14 |
|---|---|---|
| Standard | ANSI/NIST 1986 | ANSI/NIST-ITL 2011+ |
| Resolution | Fixed 500 PPI | Variable (500+ PPI) |
| Compression | None or binary | WSQ (FBI standard) |
| Slap Images | Not supported | Full support with FGP 13/14/15 |
| Segmentation | None | Fields 14.021, 14.023, 14.024 |
| File Size (10 prints) | ~5-10 MB | ~150-300 KB |
| ATF eForms | Not accepted | Required |
| FBI AFIS | Legacy support only | Preferred format |
ATF eForms Requirements
ATF's eForms system uses EBTS 8.1.0 (Electronic Biometric Transmission Specification version 8.1.0) for fingerprint validation. This standard explicitly requires:
EBTS 8.1.0 Fingerprint Requirements
- Type-14 records for all fingerprint images
- WSQ compression at 500 PPI
- Three slap images:
- FGP 13: Right four fingers (index through pinky)
- FGP 14: Left four fingers (index through pinky)
- FGP 15: Both thumbs (plain impression)
- Segmentation metadata in fields 14.021, 14.023, 14.024
- Transaction type: FAUF (Firearm Application/Update Fingerprint)
Why Slaps? ATF accepts slap images (multiple fingers) rather than individual rolled prints because they're faster to capture and sufficient for identification purposes. The FD-258 card you submit shows these three slap zones at the bottom.
What Happens During Validation
When you upload an EFT file to eForms, the system:
- Parses the NIST record structure
- Verifies Type-14 records are present (not Type-4)
- Checks WSQ compression validity
- Validates segmentation fields exist and contain proper coordinates
- Confirms FGP codes match expected slap positions
- Runs quality metrics on fingerprint images
If any validation fails, you'll see an error message and need to resubmit with a properly formatted file.
What SlapEFT Generates
SlapEFT generates fully EBTS 8.1.0 compliant EFT files with proper Type-14 records. Our files have been ATF validated and accepted for both Form 1 and Form 4 submissions.
SlapEFT EFT File Contents
- Type-1 Record: Transaction header with TOT=FAUF
- Type-2 Record: Demographics from your FD-258 card
- Type-14 Records (3): Slap fingerprints at 500 PPI
- FGP 13: Right four fingers
- FGP 14: Left four fingers
- FGP 15: Both thumbs
Technical Specifications
- Compression: WSQ @ 15:1 ratio (FBI compliant)
- Resolution: 500 PPI grayscale
- Segmentation: Fields 14.021, 14.023, 14.024 included
- File Size: Typically 150-300 KB
- Validation: Passes ATF eForms EBTS validator
Need ATF-Validated EFT Files?
SlapEFT generates proper Type-14 records with all required metadata.
Convert for $10Frequently Asked Questions
Can I convert Type-4 to Type-14?
If you have an older EFT file with Type-4 records, you cannot simply "convert" it to Type-14. The segmentation data doesn't exist in Type-4 files. You'd need to re-scan your fingerprints or FD-258 card and generate a new Type-14 file from scratch.
Why did ATF switch to Type-14?
Type-14 provides several advantages: smaller file sizes (WSQ compression), support for slap images (faster processing), and segmentation metadata (automated quality checks). This enables the fully electronic workflow that eForms provides.
Do all EFT conversion services use Type-14?
They should, but some older or lower-quality services may generate incorrect files. Always verify your EFT file is accepted by ATF eForms before considering the conversion complete.
What if my EFT file gets rejected?
If ATF rejects your file, the error message usually indicates the problem. Common issues include: missing segmentation fields, wrong FGP codes, invalid WSQ encoding, or Type-4 records instead of Type-14. SlapEFT files are tested against the ATF validator before delivery.
Where can I learn more about the NIST standard?
The full specification is available in NIST SP 500-290. For ATF-specific requirements, refer to the EBTS 8.1.0 documentation.
