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Test Drive: DxO PureRaw Preprocessor For Improved Raw Files Share This on LinkedIn   Tweet This   Forward This

14 April 2021

When DxO Labs released PhotoLab 4 with DeepPRIME, we took a deep dive into the technology that uses artificial intelligence designed for developing Raw photo files that has been trained through deep learning on millions of images. And we liked it. A lot.

We didn't mind that you had to launch PhotoLab 4 to access the power of DeepPRIME's massage of the camera's Raw data because we gave that application all four corners in our review.

But DxO recognized that it was a tough sell to get the 10 million Raw photographers in the world who are using Photoshop, Lightroom, Capture One, Exposure and other image editor users to switch to PhotoLab to enjoy the corrections to noise, chromatic aberrations, unwanted vignetting, distortion and insufficient sharpness that DeepPRIME provides.


So that company has packaged its DeepPRIME technology separately in a preprocessor that applies the corrections DeepPRIME knows how to make on your camera Raw files before you import them into your favorite image editing application.

The advantage is that you get optimized Raw files that remain Raw files so you can work on them just as you always have.


In a briefing a few weeks ago, DxO's Jean-Marc Alexia described the concept.

Preferences. Pretty simple: Pick a language and let DeepPRIME set acceleration.

Alexia compared the problem to cooking. Everybody already has their own kitchen with their own chef's knife and their own grandmother's recipe. Rather than entice them into a different kitchen with different tools and a different recipe, DxO has decided to offer to take the ingredients for that recipe and wash them the way only DxO can. With cleaner ingredients, the final plate will taste much better.

That's exactly what we did for this road test. We let PureRaw clean the DNGs converted from the Olympus ORFs and then we applied our preset for the Olympus E-PL1 before optimizing the image in Adobe Camera Raw.


We gave PureRaw a test drive on several ISO images shot with a 11-year-old Olympus E-PL1 whose maximum ISO is 1600. And ISO 1600 is what we shot.

We always wince when we see the ISO 1600 Raw file from this camera demosaicized in Adobe Camera Raw. It's noisy, period. Because we resize to 700 or 500 pixels for Photo Corners, we can live with that. But for prints, it needs to be addressed with Color and Luminance noise reduction in Adobe Camera Raw.

DxO knows all about the E-PL1 and the 14-42mm II R kit lens. So we thought we'd put PureRaw to the test with our noisy ISO 1600 images.


Using PureRaw is a three-step process that is effortless. The interface itself is clean and clear.

Step One. Drag and drop your Raw files into PureRaw's main window.

Step Two. Clck on the Process Photos button.

Step Three. Export the optimized Raw files to your preferred image editor.

All that's left is to edit the optimized Raw as you would any Raw file.

If you drop an image into PureRaw for which it does not have the DxO module for the camera and lens combination, it will let you know and provide an opportunity for you to download the module.

Modules. Until you collect all the modules for your cameras and lenses, PureRaw will offer to install them (quickly).

Do that. Always.

When it has what it needs, you can process the images. A progress bar on the bottom of the screen shows the estimated time required, which in the case of DeepPRIME can be notable. So the estimate is very helpful.

Is it accurate? At 11:44 it reported 16 minutes remaining to process three images. At 11:51, six minutes later, it reported 10 minutes remaining. At 11:56, 11 minutes after starting, it reported "About 4 minutes remaining."

Yes, it's accurate.

We should note that the MacBook Pro we tested with is a mid-2010 17-inch model with a 2.66-GHz Intel Core i7 and 8-GB RAM running macOS Mojave 10.14.6.

And we should also note that Alexia told us DxO will not offer a native M1 version of PureRaw on launch. He said it is currently Rosetta compliant. Market penetration of the M1 is currently at four percent, he noted, and turnover for the Apple market is three to four years. So they have time.


We had returned from the kitchen with a hot cup of coffee by the time our files had been written in a subfolder of the original folder, as we had directed PureRaw to do.

The program asked if we wanted to see the files in the Finder or export them to our image editing application.

Export. After confirming you want to export the file, PureRaw gives you the option to export the original too.

We exported them and they were conveniently loaded into Photoshop where Camera Raw opened them for us to process.

At that point we were done with Pure Raw.


There were three original DNG files (converted from Olympus's .ORF Raw format by Adobe's free Digital Negative Converter on import, as we always do. They ranged in size from 13.4-MB to 13.8-MB.

When PureRaw got done with them, the sizes were 43.0-Mb, 44.5-MB and 40.7-MB, a substantial bump up.

That's not a bad thing. The whole point of PureRaw is to optimize the image data, not the file size. It's nice to see it did some work.

Here are the full Exif headers for the doll's head image we're using to demonstrate PureRaw:

Well, at least the headers are smaller (with the elimination of a lot of Adobe copyright and viewer information).

Alexia explained the changes PureRaw makes are non-destructive. Anything that PureRaw finds in the original Raw file will not be overwritten, he said. That makes sense if the original data itself is preserved in the PureRaw DNG (which the larger file size seems to suggest). But it isn't clear how you would go back to that data if you wanted to.

So it would seem prudent to keep your camera Raws around if for no other reason than down the line an improved version of PureRaw might process even better derivations. Although, one might reasonably expect a new version to be able to apply the improvements to older PureRaw files.

In fact, though, it may be even more prudent to consider the PureRaw files as temporary. They can be recreated from the camera Raw files any time, after all, and you can't recreate the camera Raw files.

Plus, you save a lot of disk space that way.


We're showing you a 100 percent crop of the image below as well as the full crop version above so you can see the actual difference in noise especially. There is some optical correction that makes the images not line up perfectly, of course.

In the 100 percent crop version here, we've disabled our default preset for the Olympus E-PL1 to provide a fair comparison with with the PureRaw image for which we do not have a preset.

But in the full crop version, we applied the preset in Camera Raw to both images and adjusted from there, which represents a normal workflow. The image is perhaps small enough to obscure the improvement, but the 100 percent crop shows it clearly.


PureRaw is available directly from DxO Labs today. The company is offering a special launch price of $89.99, £79.99, €89.99 until May 31. After that it will be $129. A 30-day free trial version is also available for download.


We think the results speak for themselves. Eloquently.

Without a second thought, we're awarding all four corners to PureRaw. Except for those of you who own PhotoLab 4, it's not only a tremendous head start to your Raw edit but it makes improvements you can't.

DxO PureRaw Superbly Renders Raw Files So You Can Enjoy Even More Possibilities With Adobe Photoshop and Lightroom

When used ahead of Adobe solutions or other photo-editing programs, DxO PureRaw automatically removes digital noise and other lens defects.

Harnessing exclusive technologies developed over nearly 20 years by DxO, one of the world's leading photo-editing software creators, DxO PureRaw removes noise, chromatic aberrations, unwanted vignetting, distortion and insufficient sharpness with an unprecedented level of quality. By improving Raw images in this way, DxO PureRaw offers photographers greater creative freedom when editing in Photoshop and Lightroom. The result is a more precise and less constrained editing process.

Zero compromise between preserving details and removing noise

Say goodbye to juggling tedious compromises between preserving detail and removing noise in Photoshop and Lightroom. Using DeepPRIME artificial intelligence, DxO PureRaw automatically removes digital noise with an exceptional level of quality.

DxO DeepPRIME technology is an artificial intelligence designed for developing Raw photo files. Trained through deep learning using millions of images analyzed by DxO's laboratories, it delivers a revolutionary improvement to digital noise reduction while also demosaicing photos more effectively.

Using a traditional approach, these two operations are performed separately, with each one introducing defects that degrade the quality of the other. With deep learning, DeepPRIME adopts a holistic approach that combines these two steps into one. The information in the photo is rendered beautifully, especially in low light, noise is visibly reduced, color details are better preserved and transitions are more even and natural.

Improve even top-notch lenses

Thanks to the custom optical modules developed by DxO, DxO PureRaw automatically scrubs Raw images of the residual defects, including distortion, unwanted vignetting, chromatic aberrations and a lack of sharpness, produced by even the best lenses on the market. The software provides Photoshop and Lightroom users with a flawlessly clean slate for retouching and editing in other solutions.

Since its founding in 2003, DxO Labs has earned an international reputation for measuring and calibrating hundreds of cameras and thousands of lens using a protocol that is more precise than any other in the industry. DxO has measured the defects created by thousands of lens/camera combinations in Raw images with an extraordinary level of scientific precision for each piece of equipment and in every situation. This in-depth knowledge of the flaws and performance of each piece of photography equipment is compiled in a database of over 60,000 combinations and is the secret to why DxO PureRaw delivers the best corrections in the industry.

A new life for Raw photos

DxO PureRaw lets users revisit unusable Raw images taken with equipment that has since become obsolete. Photos are instantly made to look like they were taken with the most recent technology and limitations on ISO values are a thing of the past.

Perfection is in the details

DxO PureRaw richly and accurately reveals details in Raw files, resulting in crystal-clear images that capture every last texture. Photographers can enlarge images without worrying about decreasing the quality.

Soft, non-grainy bokeh

DxO PureRaw removes the "parasitic" grain that all cameras produce in unfocused areas and solid backgrounds. DxO PureRaw processes every part of the image and uses smart technology to differentiate between ultra-sharp areas and bokeh effects.

Incredibly simple to use

DxO PureRaw can be easily incorporated into photographers' workflow ahead of Adobe Photoshop, Lightroom or any other photo-editing software. That way, users can keep their same editing environment. DxO PureRaw couldn't be easier to use: Users simply select their images from the software's browser window or use the drag-and-drop feature, then choose their desired level of denoising and where they want to save the file. Zero sliders or complicated settings required!

Price and availability

DxO PureRaw (Windows and macOS) is now available for download on the DxO Web site for a special launch price of $89.99 instead of $129 until May 31. A free 30-day trial version is also available:

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