C4 File

What are C4 files and how to open them

Are you having problems opening a C4 file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your C4 files.

What is a C4 file?

A .C4 file is a JEDMICS C4 Data file.

These files store black-and-white raster images created and managed by the U.S. Department of Defense's Joint Engineering Data Management Information and Control System (JEDMICS). The main use is to hold engineering drawings scanned or converted into a format suitable for long-term archival, indexing, retrieval, and display under the JEDMICS imaging framework. The images are monochrome (1-bit per pixel) and are intended for technical documents rather than color or photographic content.

The format is produced by scanners or conversion tools within JEDMICS or contractors working under DoD contracts. Once generated, the files are stored in the central JEDMICS repository, associated with metadata so drawings can be retrieved or distributed in compliance with DoD technical data package requirements. These files are not typically edited pixel-by-pixel but serve as official records or reference-level images.

Technically, the files follow a tiled raster layout: there is a fixed-length header, followed by one index for a base view and one for an overview view (a downsampled full-image), and the individual tiles for those views. Compression uses the CCITT Group 4 facsimile standard. The file allows only two levels of image tiles, both always tiled (never a single monolithic strip).

How to open C4 files

Important: Different programs may use files with the C4 file extension for different purposes, so unless you are sure which format your C4 file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested nine different C4 openers which you will find listed below.

Last updated: August 25, 2026

Various apps that use files with this extension

These apps are known to open certain types of C4 files. Remember, different programs may use C4 files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about C4 file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.