Software powered by AI or machine learning appears to be the coming wave in image processing. Skylum – makers of Aurora and Luminar – Topaz Labs and Corel all emphasise the role of AI in their recent advertising and Adobe, with rather less fanfare, is developing and expanding its library of ‘neural filters’ for Photoshop.
My knowledge of how this technology works is close to zero but as far as my limited understanding goes what makes these apps different from ‘traditional’ approaches to processing is that they are ‘trained’ through analysis of vast numbers of images – Adobe claims their Super Resolution feature is trained on millions of images. (As an aside, this suggest to me that the only ‘intelligence’ at work here is the human intelligence of those creating this technology and that ‘machine learning’ is a much more apposite term.)
Many of the AI powered features highlighted in recent advertising appear to function like slightly more sophisticated versions of existing filters, or are designed to process images in ways that I have no interest in – creating flawless skin, replacing or reshaping eyes, or dropping in a completely new sky. Beyond the headline features, though, machine learning is creating some genuinely interesting and useful capabilities. I’ve already assessed one of these in two previous posts on Adobe’s Super Resolution, and a couple of days ago I downloaded a trial version of DXO’s Deep Prime, an AI powered denoising utility which is part of their PureRAW stand alone program. Here are my impressions.
First, I found a nice noisy photograph. The picture was taken in the evening by the B&O canal in Georgetown in Washington DC. While I intended to work from the original untouched RAW file I did eventually decide to boost the exposure because the original was very dark. The picture was taken with a Sony Rx100 at 1/6th of a second and f4 while stabilised on the handrail of the bridge I was standing on to get the shot. ISO was 3200. The image below is a JPEG exported from the Sony ARW file with no adjustments other than the boost to the exposure and Lightroom’s default colour noise and sharpening settings turned off. As you can see there is plenty of noise in the image. (For a closer look in each case right click on the image and ‘open image in new tab’.)
Bringing the file (or multiple files) into DXO PureRAW is straightforward though you can’t do it directly from within Lightroom. Either open PureRAW and click on ‘add photos’ or right click directly on any photo in File Explorer and select ‘open with’ DXO PureRAW. The interface is extremely simple:
Once the photo is loaded click to select the photo/s to be processed, click on ‘process photos’ and choose some basic options from the dialogue box. There are two other denoising options available but I can’t think of any reason why you would choose them over Deep Prime. You can also choose to output the processed file as a JPEG rather than DNG, but again I don’t know why you would do that since the whole point of the feature is that you can denoise using DXO technology and still complete the rest of your processing in Lightroom. Choose your detination folder and click on ‘process’. On my laptop (6th gen. i7 2.6Ghz, 16GB RAM, GTX 960M GPU) processing took around 1 minute and 50 seconds and the original 20MB ARW file ended up as a near 72MB DNG file. (I believe the size increase is down to the output file being a linear DNG file, but needless to say I don’t understand what that means.) Once processing is complete you have an ‘export to…’ option which brings up a list of installed compatible editing software.
Make your choice, click on ‘export’ and DXO will launch Lightroom and take you to the import dialogue.
The key question of course is whether it is any good. My answer is a qualified ‘yes’, but I will let you judge for yourself. Below is a JPEG from the DNG created by Deep Prime after processing. I think the programme does an excellent job of removing noise, though it does introduce some softness. That said, I don’t think I could get close to this level of denoising with Lightroom, and certainly not without introducing considerably more softness in the image.
Fortunately, PureRAW has another trick up its sleeve which draws on DXO’s more conventional processing for lens correction. The programme downloads DXO lens correction modules and applies these to the image when processing. If you don’t have the appropriate lens module installed you will be asked if you want to download it when you add a new image. In my sample image, applying both the lens module and the denoising produces a largely noise free image which retains, or in this case exceeds, the sharpness of the original. The difference between the images with and without lens correction is clearly visible, particularly in the structure of the crane and the text on the banners attached to it. That said, further editing in Lightroom does require careful use of the sharpening, texture and clarity sliders after lens correction has been applied since I think the lens correction is something of an over-correction. (Again, right click and select ‘open image in new tab’ for a closer look.)
So, why a qualified yes? Two reasons – one minor, one major. The minor one is cost. In the current offer period which runs until the end of May you can get DXO PureRAW for $89.99 / €89.99 / £79.99 but after that it reverts to the full price of $129 / €129 / £115. That’s quite expensive. For comparison, Topaz Labs standalone AI tools are mostly between $80-100 full price. Given that PureRAW is clearly aimed at the vast number of Lightroom users I suspect they could drop the price and sell many more licences than they will at the current price.
The major reason is that DXO PureRAW does not work with Fujifilm X-Trans sensors. It is possible to add a Fujifilm RAF X-Trans file and run the programme but the result is an image that looks like it was taken with a lens smeared with grease, as with the image below shot with a Fujifilm X-E2 at ISO 6400. Since processing this file – which is more than 50 percent bigger than the RX100 file – only takes around ten seconds I imagine it is just running it through some bog standard, default noise reduction process.
I have seen some reviews expressing a preference for more control over how the denoising is applied. I can understand why, but I’m happy to have something that doesn’t require yet more choices and decisions from me before I run it. If anything, I would prefer to have an option to dial back the impact of the lens correction which seems (in this module for the Sony RX100) to be a little aggressive.
If you don’t use Fujifilm cameras with X-Trans sensors, or if you have a lot of images shot on older less capable sensors, then DXO PureRAW might be worth it for you, despite the price. For people like me, who mostly shoot Fujifilm X-Trans, the calculation is different. Do I have enough noisy images from older non-Fuji sensors I want to clean up? Do I shoot enough with non-Fujifilm cameras? I like the program but I’m not quite convinced I need it.
Finally, here is the first image after processing in Deep Prime and some further processing in Lightroom.