Scans, Photos or PDFs: File Quality Requirements for Document Validation in the US

Document scan quality requirements come down to three questions: can every character on the page be read, is the whole page in the frame, and is the file complete and unlocked. A flat scan at about 150 DPI or more, one document per file, all pages present and right side up, meets the bar most text-extraction engines document. Anything below it should go back to the applicant with a precise request, not into a validation run that returns confident but wrong values.

This article is provided for informational purposes and does not constitute legal advice. Figures quoted come from vendor documentation read on October 14, 2026 and describe those products, not CheckFile. US federal rules cited reflect public sources read in October 2026; state rules vary. Consult a qualified attorney for an individual case.

What "readable" means for a document file

A file is readable when software can recover the printed text and fields without guessing, and that depends on resolution, framing, orientation and file structure rather than on how the page looks to a person. A phone photo that is perfectly clear on screen can still fail if the text is only a few pixels tall.

Amazon Textract's best-practice guidance recommends high-quality images, ideally at least 150 DPI, and advises against converting or downsampling a file that is already a PDF, TIFF, JPEG or PNG before upload (AWS, Amazon Textract best practices). A portal that silently shrinks uploads can degrade files that were fine when sent.

Microsoft documents similar thresholds for its Read model. The figures below are vendor limits, not universal rules and not CheckFile limits.

Source for the Microsoft column: Microsoft Learn, Document Intelligence Read model, input requirements. Both pages are versioned and change; recheck them before copying a number into your own intake rules.

Why US intake teams care about file quality

The United States has no single national identity document. Applicants submit state IDs, passports, W-2s, pay stubs and bank statements in many layouts, so a cropped file forces a human to guess.

For financial institutions, the Bank Secrecy Act framework administered by FinCEN requires identity verification and, for legal entity customers, the customer due diligence procedures in 31 CFR 1010.230. These rules set no DPI or pixel threshold; file quality is an operational control that lets verification be performed. OFAC sanctions screening (Treasury OFAC) also depends on names and dates of birth being read correctly.

Request, rescan or manual review: the decision table

Decide per defect, not per file. Each defect below maps to one of three actions: request a new file, request a rescan with specific instructions, or send the file to a person.

The pattern: a defect that destroys information is a request, one that only hides it from software is a rescan, and one needing judgment is a manual review.

Two synthetic examples

These cases are invented to show the decision, not drawn from any customer file.

Example 1, the half-cropped pay stub. An applicant sends a phone photo of a pay stub. The net-pay line sits at the very bottom edge and the last digit is cut off. The reader returns "2 41" with low confidence. Action: request a new photo of the full page. Do not accept the partial value.

Example 2, the locked PDF from an employer portal. A W-2 downloaded from a payroll portal opens with a password the applicant knows but your system does not. Action: ask for an unlocked export or a print-to-PDF copy. Never ask applicants to message you the password.

Telling applicants what to do

Vague instructions cause most intake failures. Send a checklist with the request, without promising any result.

• Scan flat, at least 150 DPI, in color, one document per file.
• For a photo, use daylight, a dark flat surface, a parallel phone and a small margin.
• Send every page, in order, right side up (front and back of a state ID if your process needs both).
• Do not photograph a screen; send the original PDF.
• Remove the password before sending.
• Do not crop or filter with a beauty or contrast app.

Confidence thresholds and the human fallback

A quality gate is only half of the intake; the other half is deciding what to do with uncertain extractions. Textract's guidance says business processes involving financial decisions might require confidence thresholds of 90% or higher, and that low-confidence results should be discarded or flagged for human scrutiny (AWS, Use confidence scores).

In practice, set one threshold per field type, not per file: a name, date of birth or SSN below it goes to a person.

Employment: the Form I-9 exception

Employers completing Form I-9 are in a different position. Employees choose which acceptable documents to present, and the employer may not specify which ones. USCIS explains the lists on its Form I-9 page, and the Justice Department's Immigrant and Employee Rights Section enforces the related anti-discrimination rules.

So if a chosen document's image is unreadable, the request must be about the file: ask for a clearer image of the same document, or let the employee choose another acceptable one. "Send your passport instead" is a document-specific demand and creates risk. Quality triage does not replace the employer's own examination; have counsel review rejection templates.

Keep the original, and remember readable is not authentic

Store the file exactly as received, with a timestamp, and work on copies. If a rescan replaces a file, keep both and link them.

Readable also does not mean genuine. A crisp scan of a falsified document passes every quality check in this article. Quality triage prepares a file for validation; it does not test whether a document is authentic, and it should not be described as doing so. Where authenticity is a concern, treat it as a separate control.

Collecting more files than needed is its own risk. The US has no single federal privacy statute, so obligations depend on who you are and where applicants live. California residents have rights under the CCPA (California Attorney General), other states have their own laws, and the FTC expects companies to protect sensitive data (FTC privacy and security guidance). Pay stubs, bank statements and anything showing an SSN are high-risk to store: collect only what the check requires and set a retention period.

Where this fits in the validation flow

File quality is step zero. After it comes completeness (are all required documents there), validity (dates, expiry, registers) and consistency (names, addresses and amounts agree across documents). For how extraction relates to those later checks, read Cross-Document Validation: Beyond OCR and IDP and the comparison in Best OCR software for document verification. The overall method is in the document verification guide.

Operations teams can see how these checks are organized on the pricing and plans page, and how data is handled on the security page. The checks compare fields, dates and registers across documents; they do not prove that a document is authentic.

Frequently Asked Questions

What are the document scan quality requirements for validation?

A flat, upright, complete file with every page present, one document per file, and text large enough to read, which vendors express as about 150 DPI or a minimum text height of 12 pixels on a 1024 x 768 image. Limits differ by tool, so check the one you use. US regulations such as the BSA rules do not set a DPI figure; the threshold is an operational choice.

Is a phone photo as good as a scan?

Often yes, if taken in even light, parallel to the page and without cropping. Retake photos with glare, blur or cut edges.

Should I accept a screenshot?

Prefer the original file; a screenshot loses resolution and page structure.

Can an employer reject a blurry document during the I-9 process?

It can ask for a clearer copy of the same document, but may not tell the employee which document to present. Keep the request about image quality and check USCIS guidance.

Does a good scan prove the document is genuine?

No. Quality only means the content can be read. Authenticity is a separate question that needs its own control.