Troubleshooting

Improve fax quality

Tips for crisp and easy-to-read faxes

Tested solutions

Quick fix

Quick diagnosis

Quick tip

Low resolution, wrong format, or poor contrast

Use PDF format, choose high contrast (black text on white background), font size at least 10 pt.

Quick check

Check these points first

Document saved as PDF?
Black text on white background?
Font size at least 10 pt?
Resolution at least 200 DPI?
Page margins sufficient (min. 1,5 cm)?

Possible causes & solutions

Click a cause to see the solution

1

Text is blurry or pixelated

Cause

Resolution too low or compressed image

Symptoms

Letters are hard to read, edges appear soft

Solution

Create the document with at least 200 DPI. Use PDF instead of JPEG for text documents.

2

Gray tones are too dark or too light

Cause

Fax machines can only reproduce grayscale to a limited extent

Symptoms

Photos or graphics are barely recognizable

Solution

Increase the contrast. Faxes work best with black and white documents. Avoid photos or convert them into high-contrast graphics.

3

Margins are cut off

Cause

Margins are too small, recipient fax machine prints with different margins

Symptoms

Text at the page edge is missing

Solution

Use page margins of at least 1,5 cm on all sides. Do not place important information at the outer edge.

4

Font too small to read

Cause

Font size under 10 pt, fine details are lost

Symptoms

Text becomes illegible after faxing

Solution

Use a font size of at least 10 pt, preferably 12 pt. Avoid thin or ornate fonts.

How to prevent the problem

PDF is the best format for faxes - formatting is preserved and quality is optimal.
Avoid colored backgrounds - faxes are transmitted in black and white.
Scan paper documents at a minimum of 200 DPI in black and white.

A legible fax makes a professional impression. With these tips you can ensure that your faxes are delivered optimally to the recipient.

The optimal document

For the best fax quality, your document should have these characteristics:

Format: PDF preferred
Contrast: Black text on white background
Font size: At least 10 pt, preferably 12 pt
Typeface: Clear, easy-to-read font (Arial, Times New Roman)
Resolution: 200-300 DPI

Scanning paper documents correctly

If you want to fax a paper document:

Scan mode: Black and white or grayscale (not color)
Resolution: 200 DPI minimum, 300 DPI for best quality
Format: Save as PDF
Alignment: Insert straight, skewed scans are harder to read

Avoid common mistakes

These mistakes often lead to poor fax quality:

Colored backgrounds: Often become too dark or unreadable
Photos: Usually do not fax well - avoid if possible
Small fonts: Anything under 10 pt becomes hard to read
Thin lines: May disappear or appear broken

Frequently asked questions

Which file format delivers the best fax quality?

PDF delivers the best quality for faxes. The format preserves formatting, fonts, and layout exactly. JPG and PNG also work, but PDF is ideal for text documents.

What resolution should I use?

At least 200 DPI (dots per inch). For very detailed documents or small fonts, 300 DPI is better. Higher resolutions provide little benefit because fax machines have limited resolution.

Are colors transmitted?

No, faxes are generally transmitted in black and white or grayscale. Colored content is automatically converted to grayscale. Check in advance whether your document is easy to read in black and white.

Problem still not solved?

If none of the solutions worked, there may be a technical issue. Our support team will be happy to help.

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