Do Raw Developers Use the Embedded JPEG as a Color Reference?

In a recent thread on DPReview, someone made an interesting claim: that some raw developers use the embedded JPEG in raw files as a reference for color. The idea seems to be that the raw converter might read this in-camera-rendered preview to guide or inform its own color processing. That assertion caught my attention, and not in a good way.

I’ve used many raw developers over the years, including Lightroom, Adobe Camera Raw, Raw Therapee, Phocus, and Iridient Developer. None of them, in my experience, reference the embedded JPEG when producing a developed raw image. They rely instead on camera profiles, input color spaces, and the chosen rendering intent (such as Adobe Standard, Camera Matching, or custom DCP/ICC profiles). I do have limited experience with the Sigma raw developer, which briefly displays a preview derived from the embedded JPEG while it computes its own image. But that preview is evanescent, a placeholder rather than a reference. It’s there to provide responsiveness, not guidance.

Even if a raw converter did access the embedded JPEG, what would “using it as a reference” mean, exactly? Presumably, it would mean trying to match its colors, in effect overriding the color profile or LUT selected by the user. That would be a peculiar choice, particularly in applications marketed to photographers who want control and consistency.

I’ve also tested the effect of changing the color space of the embedded preview JPEG, for example, toggling between AdobeRGB and sRGB as the in-camera output space. In every raw developer I’ve tried, this has no effect on the colors in the developed image. That’s strong evidence that the preview JPEG is ignored once the raw data is ingested.

Of course, camera manufacturers sometimes include proprietary metadata that can be used by their own bundled software (e.g., Nikon’s Picture Controls, Fujifilm’s film simulations). In those cases, the camera settings may influence rendering — but that’s not the same thing as using the JPEG image itself as a color guide.

Of course, both the JPEG preview and the developed raw image, when using the “as shot” white balance, will reflect the same in-camera white balance setting. That may give the illusion that the raw developer is referencing the embedded JPEG, but it is not. The white balance metadata is stored independently in the raw file and simply applied by the raw converter when “as shot” is selected. The preview JPEG and the raw developer are both drawing from the same source metadata, not from each other. This is an important distinction: the raw developer reads the white balance metadata, not the JPEG pixels. The similarity in color balance is a result of common input, not cross-referencing.

So, as far as I can tell, the embedded JPEG in a raw file is just a preview that is useful for fast image browsing and chimping, but not a reference for image development. If you know of a counterexample, I’d love to hear about it. But for now, I remain skeptical.