RFC 3950

RFC 3950: Tag Image File Format Fax eXtended (TIFF-FX) - image/tiff-fx MIME Sub-type Registration 💖

Okay bestie, this is RFC 3950 🎀 It came out of the Network Working Group in February 2005 and it's a Standards Track doc. The authors are Lloyd McIntyre (Consultant), Glenn Parsons (Nortel Networks), and James Rafferty (Brooktrout Technology). It obsoletes RFC 3250 🦋 The title block doesn't have an Updates line, so there's nothing it updates.

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Status of This Memo ✨

So this doc is an Internet standards track protocol for the Internet community, and it's literally asking for discussion and suggestions to make it better 🫶 If you want the current standardization state and status, check the current edition of the "Internet Official Protocol Standards" (STD 1). Distribution of this memo is unlimited, so share it with everyone 🌸

Copyright Notice 💅

Copyright (C) The Internet Society (2005).

Abstract 🧚

Okay so this doc is all about registering the MIME sub-type image/tiff-fx. The encodings come from File Format for Internet Fax and its extensions 🍓

1. Introduction 🌈

Bestie, the intro is basically the abstract again, just with the citation: this doc registers the MIME sub-type image/tiff-fx, and the encodings are defined by File Format for Internet Fax [TIFF-FX] and its extensions 💖

It's also a product of the IETF Internet Fax Working Group, so you know it's serious ✨

Now the key words. The words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be read as described in BCP 14, RFC 2119 [REQ]. So when you see those in caps, they're doing real work, not just vibes 😭🔥

2. TIFF-FX Definition 👑

Tag Image File Format Fax eXtended (TIFF-FX) is defined in detail by RFC 3949, "File Format for Internet Fax" [TIFF-FX] 🎀

This section gives you a quick scope and feature overview as background, but if you want the full feature and technical details, go read the original TIFF-FX spec (File Format for Internet Fax). Don't skip it, the real answers live there 🙈

2.1. TIFF-FX Scope 🦋

Okay so this doc defines a TIFF-based file format for standardized messaging-based fax over the Internet 💜 It specifies the TIFF fields and field values needed for compatibility with the existing ITU-T Recommendations for Group 3 black-and-white, grayscale and color facsimile. TIFF has historically been used for fax image files in things like store-and-forward messaging. Implementations that support this file format for import/export may choose to support it as a native format too 🌈

It also recommends a TIFF file structure that works with low-memory and page-level streaming implementations. Iconic efficiency energy 🔥

Unless otherwise noted, the current TIFF specification [TIFF] and selected TIFF Technical Notes [TTN1, TTN2] are the primary references for describing TIFF and defining TIFF fields. This doc is the primary reference for defining TIFF field values for fax applications. So TIFF is the base, and this is the fax-specific layer on top ✨

2.2. TIFF-FX Features 💖

Some of the features of TIFF-FX are:

• TIFF-FX can describe bilevel, grayscale, palette-color, full-color and mixed content image data. Literally every kind of image 😭
• TIFF-FX includes a number of compression schemes so developers can pick the best space or time tradeoff for their apps 🧚
• TIFF-FX is designed to be extensible and to evolve gracefully as new needs come up. It's giving future-proof 🫶

3. MIME Definition 🎀

Okay so this is the important part for the MIME type. This doc defines the image/tiff-fx MIME sub-type to refer to TIFF-FX Profiles J, C, L and M encoded image data, plus any future TIFF-FX extensions, or a subset of them 🦋

The image/tiff-fx content type MAY be used when black-and-white image data is encoded using TIFF-FX Profiles S or F, or a subset. However, the image/tiff content type SHOULD be used for that case. So you're allowed to use tiff-fx for S or F black-and-white, but plain tiff is the preferred choice 💅✨

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(Part 1 of 2. Part 2 picks up with Section 4, IANA Registration, and everything after it 🌸)

Intellectual Property ✨

okay bestie, so the IETF is basically saying "we are not picking a side on whether anyone owns the tech in this doc" 💅 It takes no position on whether any Intellectual Property Rights or other rights might be claimed over implementing or using the technology described here. It also doesn't say whether any license under those rights would or wouldn't be available, and it hasn't independently gone hunting for any of those rights either 🙈 If you want the IETF's rules on rights in IETF Documents, check out BCP 78 and BCP 79 📚

Copies of IPR disclosures sent to the IETF Secretariat are a whole thing, and so are any assurances of licenses that might be offered. Same goes for the result of anyone trying to get a general license or permission to use those proprietary rights, whether they're an implementer or a regular user of this spec. All of that can be found in the IETF on-line IPR repository at http://www.ietf.org/ipr 🌸

The IETF also wants to hear from anyone who knows about copyrights, patents, patent applications, or other proprietary rights that might cover technology needed to implement this standard. Send that info to the IETF at ietf-ipr@ietf.org 🫶

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Acknowledgement

Funding for the RFC Editor function is currently provided by the Internet Society 🎀 Shoutout to them for keeping the lights on for the RFC Editor! 🌈