RAW vs JPEG: what is actually inside each file
Everyone knows RAW is "better" and almost nobody can say what is in the file. That gap matters, because most of the practical questions, why a RAW looks flat, why the camera JPEG looks nicer, why a converter can be instant one moment and take five seconds the next, are answered by what is physically inside each format. This is that answer, without the religion.
What a RAW file holds
A camera sensor is a grid of photosites, each behind a red, green or blue filter in a repeating pattern, usually the 2 by 2 Bayer layout, or Fujifilm's 6 by 6 X-Trans. Each site records one number: how much light arrived, at 12 or 14 bits of precision, linear, meaning twice the light is twice the number. A RAW file is that grid of numbers, compressed losslessly or nearly so, plus everything the converter needs to make sense of it: the pattern, the black and white levels, the white balance the camera measured, a color matrix that maps this sensor's primaries to real colors, the lens, the exposure, the time, and the maker's notes.
What it does not hold is a picture. No pixel in a RAW has a full color; each has one channel. No tone curve has been applied; the data is linear, and a linear image on a screen looks dark and flat. That is not a flaw. It is the point: nothing has been decided yet.
What a JPEG holds, and throws away
A JPEG is the decided version. Every pixel has full red, green and blue, 8 bits each, in a color space (nearly always sRGB) with a gamma curve already applied so it looks right on a screen. To get there, the camera or the converter demosaiced the grid, applied white balance and the matrix, mapped 14 bits of linear data onto 8 bits of curve, then compressed with a method that discards fine detail the eye is bad at seeing, mostly in color, more as the quality setting drops.
Three things are gone for good in a JPEG: the highlight headroom above what the curve kept, the deep shadow precision that 14 bits held and 8 do not, and the freedom to change white balance without cost. That is the whole argument for shooting RAW, and it is a good one. It is also why a JPEG is the right thing to deliver: it is the finished picture, it is a tenth of the size, and every screen on earth opens it.
| RAW | JPEG | |
|---|---|---|
| Per pixel | One channel, 12 to 14 bit, linear | Three channels, 8 bit, gamma encoded |
| White balance | Recorded, not applied | Baked in |
| Highlight headroom | Whatever the sensor kept | Whatever the curve kept |
| Typical size, 24 MP | 25 to 50 MB | 5 to 12 MB |
| Opens in | A decoder that knows the camera | Everything |
| Is a picture | Not yet | Yes |
The JPEG inside the RAW
Here is the part that surprises people: every RAW from a modern camera contains a JPEG. The camera renders one at capture, the same picture you see on the back screen, and stores it inside the RAW so the camera, and any viewer, can show the file without decoding it. On most Canon, Nikon and Fujifilm bodies it is full size; on many Sony, Olympus and Panasonic bodies it is smaller, around 1616 by 1080 or 1920 by 1440.
That embedded JPEG is why a culling app can show four thousand frames in seconds, and why a browser converter can show your card instantly and then take a few seconds per file when you ask for a real develop. The instant one is the camera's render, copied out. The slow one is the sensor data, cooked fresh. The JPEG hiding inside your RAW file goes brand by brand.
Why a developed RAW looks flat
Open a RAW in a neutral converter and it looks flatter, softer and often darker than the camera's JPEG of the same frame. Nothing is wrong. The camera JPEG carries a Picture Style, Picture Control, Creative Look or Film Simulation: a contrast curve, a saturation bump, sharpening, noise reduction, sometimes lens corrections and a highlight priority mode. A neutral develop applies white balance and the color matrix, then a plain curve, and stops. It is showing you the data. Every editor's default profile is a step toward the camera look; Adobe Color, Camera Matching, the maker's own app. Neutral is where those start.
When to shoot RAW plus JPEG
Shooting both writes the finished picture and the negative side by side. It costs card space and a little buffer depth, and it earns its keep in exactly two situations. The first is a rush: the JPEGs go out tonight, the RAWs get the real edit later, and the rush workflow is built around that. The second is a camera whose embedded preview is small, where a full size JPEG next to the RAW saves a develop step when someone needs a frame now. For everything else, RAW alone plus a converter that can pull the preview when you need it covers the same ground with half the files.
None of this changes what culling is. Whether you shoot RAW, JPEG or both, the four thousand frames still need the obvious misses cleared before you can choose. That is what Kepla does on your Mac: it reads the embedded JPEG where the answer is clear, opens the RAW where it is not, and leaves the choosing to you. Request Founding Access.
FAQ
Is a RAW file an image?
Not yet. It is sensor data with the information needed to make an image. A converter has to demosaic it, apply white balance and color, and map it to a curve before it is a picture.
Does every RAW contain a JPEG?
Every RAW from a modern camera does. The size varies by brand: full size on most Canon, Nikon and Fujifilm bodies, smaller on many Sony, Olympus and Panasonic bodies.
Should I deliver RAW or JPEG to clients?
JPEG, almost always. It is the finished picture and opens everywhere. Handing over RAW is a separate decision covered in its own article.
Why is a RAW so much bigger than a JPEG?
It holds 12 to 14 bits per photosite with lossless or near lossless compression; a JPEG holds 8 bits per channel with lossy compression tuned to what the eye misses.
Never cull alone at 1 AM again.
Kepla for Mac clears the obvious misses from a card, names the reason on every frame it sets aside, and leaves the choosing to you. Nothing is ever deleted, moved or renamed. Free through the private preview · the first hundred photographers keep it at $99 a year.