Summary
A blurry or faded fax is almost always a scanner settings problem. The quality of the original scan is important because fax transmission compresses data during delivery. The right DPI for the document type, correct contrast settings, appropriate colour mode, and a clean PDF export all contribute to a fax that reads clearly at the other end. Faxburner’s “Scan” feature makes it easy by letting you photograph documents with your phone camera and fax them online.
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Sending a fax from a scanner is straightforward (especially when you use an online faxing service). Getting it to arrive clearly is where most people run into problems.
A fax that arrives blurry, faded, or with text cut off at the edges rarely comes down to the fax service. It usually comes down to scanner settings that weren’t adjusted for faxing specifically. The steps to send are simple enough. The settings that determine whether your recipient can actually read what you sent are worth understanding.
How to Fax a Document from a Scanner
Whether you’re using FaxBurner or a combined scanner/fax machine, the process follows the same basic steps.
- Scan the document: Open the scanner lid, place your document face down on the glass, and carefully align it. Any misalignment will show in the final fax. Select your resolution in DPI and start the scan.
If you’re using Faxburner: skip the above and use the app’s “Scan” feature instead! This lets you photograph a document using your phone camera, crop it as needed, and quickly fax it online.
- Upload or attach: Upload the scanned file through the FaxBurner app, or attach it to an email and send it to the provided fax address. If you have a combined printer/scanner/fax machine, you can send directly after scanning.
- Enter the fax number: Enter the recipient’s fax number accurately. Double-check before sending.
- Send and confirm: Send the document and keep the confirmation for your records.
No External Scanner Needed: Scanning with FaxBurner
Faxburner’s “Scan” feature lets you scan and send documents without needing an external scanner. Just follow these quick steps:
- Photograph the document with your phone
- Crop the edges within the app
- Attach it to your fax and send it online through the app
For many people, this is the simplest way to scan and send a document because it eliminates the need for an external scanner or fax machine entirely. Try FaxBurner here or keep reading for more tips on how to scan your documents if you need to use a dedicated external scanner for any reason.
Why Scan Quality Matters More for Faxing Than for Printing
When you print out a scanned document, the printer will usually compensate for a document’s low resolution by adjusting ink density and sharpening edges, but fax transmission doesn’t work that way. The scanned image is converted into data and transmitted as-is, so what your recipient gets is a direct reproduction of what you uploaded, without enhancement or correction.
Fax transmission also compresses data during delivery to reduce file size and transmission time. That compression can further reduce image quality, especially if the original scan is already borderline. A document that looks acceptable on your screen can arrive at the receiving end looking washed out, blurry, or unreadable.
That’s why it’s worth taking a few minutes to get the scanner settings right before sending anything important.
Choosing the Right DPI for Faxing
DPI (dots per inch) is the most important scanner setting for fax quality. It determines how much detail is captured in the scan. Higher DPI means more detail and a larger file. Lower DPI means less detail and a smaller file.
For faxing, the relationship between DPI and quality is direct: too low, and the recipient struggles to read the document; too high, and the file may be too large to transmit efficiently. The right setting depends on what you’re sending.
| DPI Setting | Best For | Notes |
|---|---|---|
| 100 DPI | Draft documents, internal use only | File size is small, but the quality is too low for most business faxing |
| 150 DPI | Simple text, low-priority forms | Acceptable for plain text; may struggle with small print |
| 200 DPI | Standard text documents, most forms | The recommended minimum for business faxing |
| 300 DPI | Mixed text and graphics, signatures | Good balance of clarity and file size for most fax use cases |
| 600 DPI | Fine print, detailed images, legal documents | Highest clarity but larger file size; may slow transmission |
Getting Contrast and Brightness Right
DPI determines sharpness. Contrast and brightness determine whether the content on the page is readable once it arrives.
Contrast
Contrast controls the difference between the darkest and lightest parts of the image. For text-heavy fax documents, higher contrast usually produces cleaner results because it makes text darker and backgrounds lighter, which is easier to read.
If your scanned document looks grey or washed out, increasing contrast is usually the fix. If the text looks too heavy or details are being lost, reduce it slightly.
Brightness
Brightness controls the overall lightness of the image. If the scanned page looks too dark, increase brightness. If it looks too light, reduce it.
The right balance depends on the original document. A printed document on bright white paper usually scans well at default settings. A document on colored paper or with handwriting may need adjustment.
A useful rule of thumb: scan at default brightness first, review the preview, then adjust if the background looks grey or the text looks faded. Don’t adjust blindly; check what the scan actually looks like before sending.
Related Reading:
- How to Fax Documents From Your Computer (and Online) Without a Fax Machine
- How Do I Send a Fax From My Printer?
- Why Is My Fax Not Working?
Color Mode: Color, Greyscale, or Black and White?
Most scanners offer three color modes. For faxing, the color mode choice matters for both quality and file size.
- Black and white (monochrome): The fastest to transmit and the smallest file size. Works well for text-only documents and forms. Can lose detail in photos or documents with light grey areas.
- Greyscale: Captures shading and subtle differences in tone. Better for documents with photos, diagrams, or handwriting. Larger file than black and white, but still manageable.
- Color: Not recommended for faxing. Most fax machines and services print in black and white, so color adds file size with no benefit at the receiving end. It can also increase transmission time.
For most business faxing, black and white works best for clean text documents, and greyscale for anything with photos, handwriting, or mixed content.
File Format: PDF vs. Other Formats
After scanning, your document needs to be saved in a format the fax service can process. PDF is the best choice for faxing in almost every situation.
- PDF: Preserves formatting, is universally compatible, and can be compressed without significant loss of quality. FaxBurner accepts PDF as the primary format.
- TIFF: Good quality but large file sizes. Some fax services accept TIFF, but it’s not always necessary and can slow transmission.
- JPEG: Introduces compression artifacts that can make text harder to read after transmission. Not recommended for text-heavy documents.
- PNG: Better quality than JPEG but larger file sizes; not ideal for faxing text.
If your scanner doesn’t export directly to PDF, most operating systems let you print to PDF from the scanner software. This is usually the cleanest option.
Preparing the Document Before You Scan
Scanner settings matter, but so does the document itself. A few minutes of preparation before scanning can prevent problems that no settings adjustment will fix.
Clean the Original
Remove any staples, paper clips, or binding before placing the document in the scanner. Anything that causes the paper to sit unevenly on the glass will create a blurry or uneven scan.
Clean the Scanner Glass
Dust, fingerprints, and smudges on the scanner glass show up as spots or streaks on the scanned image. Wipe the glass with a clean, dry, lint-free cloth before scanning important documents. Never use paper towels or abrasive materials, as these can scratch the glass.
Align the Document Carefully
Place the document you wish to scan flush against the corner or alignment guides on the scanner bed’s glass. Even a slight angle can make text appear skewed or cut off at the edges. If your scanner has an automatic document feeder, make sure the pages are evenly stacked and the guides are adjusted to the paper width.
Check your Margins
Some fax services crop a small amount from the edges of the page during transmission. If your document has text close to the edges, check the margin settings before scanning. A safe margin of at least 10mm on all sides reduces the risk of content being cut off.
Pre-Scan Review
Most scanner software shows a preview before the final scan. Use this preview to your advantage. It allows you to check for misalignment, shadows at the edges, spots on the glass, or anything that could affect readability. It takes ten seconds and can save you from sending a document that has to be resent.
Troubleshooting Common Quality Problems
If your faxes are arriving with quality issues, this table covers the most common causes and fixes:
| Problem | Likely Cause | Fix |
|---|---|---|
| Blurry or unclear text | DPI is set too low, or the document is misaligned | Increase DPI to at least 200; realign and re-scan |
| Spots or streaks across the page | Dust or debris on the scanner glass | Clean the glass with a lint-free cloth and re-scan |
| Text cut off at edges | Document not centered, or margins are too narrow | Reposition the document; check margin settings before scanning |
| File too large to send | DPI is set too high for a simple document | Reduce DPI to 200-300, or compress the PDF before sending |
| Fax arrives blank | The wrong side of the document was scanned | Re-scan face down on the glass; check scanner orientation guide |
| Faded or grey appearance | Brightness is set too high | Lower brightness and increase contrast in scanner settings |
Scanning & Sending With FaxBurner
Once you have a clean scan saved as a PDF, sending it with our online fax service takes under a minute. You can upload the file directly through Faxburner’s free iPhone app, or attach it to an email addressed to your FaxBurner send address with the recipient’s fax number in the subject line.
Every fax generates a delivery confirmation, so you know the document arrived. Sent faxes are stored in the cloud and accessible from any device, so there’s no need to keep a physical copy of your confirmation printout.
FaxBurner offers a free account that gives you access to a free, disposable fax number (paid subscriptions give you a permanent number), 25 inbound fax pages a month, and five outbound fax pages total over the lifetime of your free account.
Frequently Asked Questions about Scan Quality for Faxes
Does scanning at a higher DPI always produce a clearer fax?
Not necessarily. Beyond a certain point, higher DPI stops improving fax quality. A traditional fax transmission re-samples your document to a fixed resolution standard. Most fax services and machines transmit at roughly 200 DPI (“fine” mode), with some supporting a higher “superfine” setting. A 600 DPI scan gets compressed down to that grid on the way out, so the extra detail is discarded while the larger file slows transmission. Scanning at 200–300 DPI captures everything the fax standard can actually carry. The only exceptions are fine print or detailed graphics, where starting higher gives the re-sampling more to work with before it down-converts.
Can the recipient’s fax machine or service affect how my fax looks?
Yes. A clean scan only controls your side of the transmission. The receiving machine decides how the document is rendered. An older thermal fax, a low-toner printer, or a machine set to a lower resolution mode can degrade a perfect scan after it arrives. You can’t change the recipient’s hardware, but a sharp, high-contrast original gives their machine the best possible source to reproduce.
How do I fax a multi-page or double-sided document from a scanner?
For multi-page documents, scan all pages into a single PDF rather than sending separate files. FaxBurner lets you combine pages into one document before sending, which keeps them in order and counts as one fax. For double-sided originals, scan each side as its own page; flatbed scanners only capture the face on the glass, and most scanners won’t auto-duplex unless they have an automatic document feeder that supports it. If you’re using an ADF, fan the stack first and set the paper guides so pages don’t pull through skewed.
Will a scanned signature stay legible, and is a faxed signature still valid?
A signature stays legible if you scan it in greyscale at 300 DPI. Avoid black-and-white mode, which can break up the thin, varied strokes of handwriting. Faxed signatures have been widely accepted for most routine business purposes for decades, but high-stakes documents such as certain contracts, legal filings, or notarized forms may require an original wet signature or a verified e-signature. These requirements also vary by document type and jurisdiction, so check before you send!
How long does it take to send a scanned fax?
Most standard documents sent through FaxBurner transmit in seconds. Note that larger files may take longer to send.
Does a delivery confirmation mean my fax was readable?
No. A delivery confirmation tells you the transmission completed and the receiving machine accepted the file. It says nothing about whether the content is legible at the other end. A blurry, skewed, or faded document will still generate a successful confirmation. That’s why doing everything you can to fax a quality scan at the front end is critical for sending a document your recipient can actually read.
