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Home > Guides > Faxing in color
No: fax is a black-and-white technology. Every fax machine and fax service converts your document to 1-bit black-and-white before sending, so colors become shades of gray. Light colors like yellow can vanish completely, and dark colors merge into black. If color carries meaning in your document, redesign it for black-and-white first.
The fax standard everyone uses dates to the 1980s, when a fax traveled over an ordinary phone line as audio tones. There was barely enough bandwidth for black-and-white dots, let alone color, so the standard was built around 1-bit images: each dot is black or white, nothing between. A color fax standard was actually written in the 1990s, but almost no manufacturer implemented it, so it effectively does not exist. Forty years later, every machine in the world still speaks the black-and-white version, and any fax you send gets flattened to black-and-white whether you like it or not.
| Original color | What the recipient sees |
|---|---|
| Black text | Black text: perfect |
| Dark blue or red text | Dark gray: readable, but red and blue are indistinguishable from each other |
| Blue ink signature | Medium gray: readable but washed out, loses the "original ink" look |
| Yellow highlighter | Often completely invisible: the most common fax casualty |
| Light gray or pastel text | May vanish or turn into unreadable speckle |
| Color-coded charts | Shades of gray that may be impossible to tell apart: add labels |
Do the conversion yourself instead of letting the fax machine guess. Print the document in grayscale on your own printer first: what you see is close to what the recipient gets, and you will spot the vanishing yellows and merging grays before they become someone else's problem. Replace color coding with labels, patterns, or bold text. Sign in black ink rather than blue: the classic blue-ink "original signature" turns into a washed-out gray that looks like a photocopy of a photocopy, which defeats the purpose. And if the document truly needs color to be understood, a medical image, a color-coded map, fax is the wrong tool: mail a printed copy or use a secure file share instead.
Send the black-and-white-optimized version by fax to satisfy their process, and mention in your cover note that a color original is available another way if they need it. Offices that require fax usually care about the document arriving through their approved channel, not about the color fidelity. Describe the fax to your AI assistant through LetterAgent: you get a per-fax quote with the page count verified, approve the exact total, pay once, and it is sent to a US or Canadian fax number. Fax is in private testing right now.
Ready to fax it? Fax with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is sent.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
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