RFC 2302

RFC 2302 🎀 Tag Image File Format (TIFF) - image/tiff MIME Sub-type Registration

okay bestie, let's start with the header card 💅 This is a Standards Track doc from the Network Working Group, dated March 1998. It was written by G. Parsons (Northern Telecom), J. Rafferty (Human Communications), and S. Zilles (Adobe Systems, Inc.) ✨ Heads up: the header doesn't list anything it obsoletes or updates, but the abstract says it refines an earlier sub-type registration in RFC 1528 🦋

Status of this Memo 🌸

so this is an Internet standards track protocol for the Internet community, and it's basically asking for discussion and suggestions for improvements 🫶 For the standardization state and status of this protocol, check the current edition of the "Internet Official Protocol Standards" (STD 1). Distribution of this memo is unlimited 🔥

Copyright Notice 🦋

Copyright (C) The Internet Society (1998). All Rights Reserved.

Overview 💖

this doc describes the registration of the MIME sub-type image/tiff. The baseline encoding is defined by [TIFF] 🎀

Internet Fax Working Group 🧚

this doc is a product of the IETF Internet Fax Working Group, so all comments should be sent to the email distribution list at <ietf-fax@imc.org> 💌

1. Abstract ✨

same energy as the overview, just in the official spot: this doc describes the registration of the MIME sub-type image/tiff, and the baseline encoding is defined by [TIFF]. It refines an earlier sub-type registration in RFC 1528 [TPC.INT] 🌈

2. TIFF Definition 💅

TIFF (Tag Image File Format) Revision 6.0 is defined in detail by Adobe in [TIFF]. The documentation can be grabbed from Adobe at:

  Adobe Developers Association
  Adobe Systems Incorporated
  345 Park Avenue
  San Jose, CA 95110-2704

  Phone: +1-408-536-6000
  Fax:   +1-408-537-6000

A copy of this specification can also be found in:

ftp://ftp.adobe.com/pub/adobe/devrelations/devtechnotes/pdffiles/
tiff6.pdf

so, while this section gives a quick scope and feature description as background, the original TIFF specification [TIFF] is where you go for the complete feature and technical details 📚✨

2.1 TIFF Scope 🌷

TIFF describes image data that typically comes from scanners, frame grabbers, and paint- and photo-retouching programs. TIFF is not a printer language or page description language. The purpose of TIFF is to describe and store raster image data. A primary goal of TIFF is to provide a rich environment within which applications can exchange image data. This richness is required to take advantage of the varying capabilities of scanners and other imaging devices. Though TIFF is a rich format, it can easily be used for simple scanners and applications as well, because the number of required fields is small 💖

2.2 TIFF Features 🦋

some of the features of TIFF (from [TIFF]) are:

• TIFF is capable of describing bilevel, grayscale, palette-color, and full-color image data in several color spaces.
• TIFF includes a number of compression schemes that allow developers to choose the best space or time tradeoff for their applications.
• TIFF is designed to be extensible and to evolve gracefully as new needs arise.
• TIFF allows the inclusion of an unlimited amount of private or special-purpose information.

3. MIME Definition 👑

3.1 image/tiff 🍓

the image/tiff content-type was previously defined in RFC 1528 as containing TIFF 6.0 encoded image data, with specific reference made to a subset known as TIFF Class F. This doc re-defines the original image/tiff definition to refer to all of the profiles and extensions that build on TIFF 6.0 [TIFF] encoded image data, which lines up with existing practice for TIFF aware Internet applications. This definition gets an upgrade from the new "application parameter" (section 3.2), which lets you identify a specific subset of TIFF and TIFF extensions for the encoded image data 🌈

3.2 Application parameter 🧚

ok, so there are cases where it's handy to identify the application that the content of an image/tiff body is meant for. Typically, this helps the recipient pick a suitable rendering package to handle the display or processing of the image file. So an optional "application" parameter is defined for image/tiff to identify a particular application's subset of TIFF and TIFF extensions for the encoded image data, if it's known. No values are defined in this document 🫶

Example using a fictional value 'foo':

              Content-type: image/tiff; application=foo

There's no default value for application. The absence of the application parameter indicates that the encoded TIFF image is Baseline TIFF, or that it's not necessary to identify the application. It's up to the recipient's implementation to determine the application (if necessary) and render the image to the user 💅✨

Full Copyright Statement 💖

Copyright (C) The Internet Society (1998). All Rights Reserved. 🎀

Okay bestie, here's the legal bit 💅 Anyone can copy and share this document, and translations of it too. People can also make derivative works that comment on or explain it, or help people implement it, and publish and distribute those in whole or in part, without restriction of any kind. The one catch is that the above copyright notice and this paragraph have to be included on all such copies and derivative works 📜

The document itself can't be modified in any way, though. You can't remove the copyright notice or the references to the Internet Society or other Internet organizations 🙅‍♀️ There are two exceptions: you can change it as needed for developing Internet standards (and then the copyright procedures in the Internet Standards process must be followed), or you can translate it into languages other than English 🌈

The limited permissions above are perpetual, meaning they will never be revoked by the Internet Society or its successors or assigns. Forever and ever 🦋✨

This document and the information in it are provided on an "AS IS" basis, and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 😭 Translation: they're not promising it's perfect, so read it carefully and test it 🫶