What is a RAW File?
A RAW file contains minimally processed measurements from a camera sensor plus metadata needed to interpret them. It is not a single universal layout, and camera vendors may use different formats.
How RAW Files work
A camera RAW file packages sensor-derived samples with the calibration and capture metadata required to turn them into a viewable image. For color-filter-array sensors, development includes black-level correction, demosaicing, white balance, color transformation, and tone mapping, each of which can change the rendered result. RAW therefore functions as a source master in an imaging workflow, while previews and standardized exports serve selection, editing interchange, and delivery.
Key facts
- 1RAW does not necessarily mean uncompressed. Vendor formats may use lossless or lossy compression while still preserving sensor-oriented data for a later development process.
- 2A camera-generated preview can differ from a fresh RAW conversion because it reflects the camera’s picture style, white balance, and rendering software at capture time.
- 3Correct development depends on model-specific metadata such as sensor layout and black levels. A decoder may open older files yet fail or misrender samples from a newer camera model.
When RAW Files matter
Retain RAW input when an imaging workflow needs greater latitude over demosaicing, exposure, dynamic range, or color. Distribution requires development into a broadly supported format, and decoder compatibility varies by camera.
Common use cases for file formats & compression
These examples cover file formats & compression broadly, not specifically RAW Files.
- Accepting heterogeneous uploads while producing a controlled set of delivery formats.
- Moving assets between cameras, editors, browsers, archives, and downstream APIs.
- Separating long-lived source files from compact derivatives optimized for a particular channel.
Working with file formats & compression
This guidance covers file formats & compression broadly, not just RAW Files.
A parser reads the file structure, identifies contained streams and metadata, and exposes them to a decoder or application. Conversion usually decodes the source representation and writes compatible information into a different structure or encoding.
This category covers file and bitstream formats, their structures, and the compression methods they use. A filename extension can be misleading, so evaluate the detected format, decoding support, metadata, transparency, color, timing, patents, and archival needs before choosing an output.
What you gain
- A suitable format preserves the properties a workflow actually needs.
- Standardized structures allow files to move between compatible tools and systems.
- Format conversion can improve delivery size, editability, or long-term accessibility.
What it costs
- Modern formats can save bandwidth but may need fallbacks for older clients and production tools.
- Converting to a simpler format can discard transparency, animation, metadata, color precision, or editability.
- Archival suitability, browser support, and editing support often favor different choices.
Before production
- 1Inspect the detected container, codec, MIME type, and magic bytes instead of trusting a suffix.
- 2Verify decoder support and preserve metadata, color, transparency, or timing when required.
- 3Retain the source when the chosen delivery format is lossy or tied to current software.