Photo Restoration, Photoshop vs AI Gigapixel
There’s particular photograph of my Grandmother that I have always liked but the photo itself has been badly damaged over the years. It was taken in 1908, when she was 18 years old wearing a dress that was made by her mother. The dress was pink (no, not a colour photograph but she lived to a good old age and did tell me it was pink!).
I had done a restoration of the picture in about 1997, but the scanner, upsizing and editing software that I had at the time was obviously not as good as the hardware and software of today. Consequently, I had never been totally satisfied with what I had achieved. I’ve recently been reading about upsizing software (tried some free stuff that didn’t impress) and came across some glowing reports of Topaz Lab’s “AI Gigapixel”…Topaz claims…
Enlarging your image without losing detail has always been impossible…until now. Upscale your photos by up to 600% while perfectly preserving image quality.
Topaz Labs advertising
At a price of $99.99, it has to be good hasn’t it? Well, at any rate, Topaz Labs offer a 30 day trial period, so I downloaded it and tried it out on a couple of photographs. I also have the Adobe Photographers’ package, which I use almost daily, but not often to upsize.
The Process
Firstly, I scanned the photograph of my Gran at 600 pixels per inch, using an Epson V500 Photo scanner. This resulted in a perfectly acceptable image that retained as much detail in the original file as I could squeeze out of it, though the original photograph isn’t all that sharp. Here is a part of the scan:
Without doing any further editing, I set about upsizing the image by 300%, first using Photoshop then using AI Gigapixel. Topaz Labs do not jest when they say that AI Gigapixel “takes a long time to process your image”. I have an i7 processor with an Nvidia GeForce GTX 770 graphics card and 24 Gig of RAM and the upsize took minutes. So, what is it up to? I had to go and put the kettle on while it chugged away. Photoshop took seconds to do its calculation.
The image below shows both upsized photos, side by side. The Photoshop version (left) has been upsized in Photoshop 2020, using the “Preserve details 2” algorithm, with “reduce noise” set at 5%. On the right is the AI Gigapixel version, upsized by the same percentage. There isn’t a lot to choose between them on the face of it. Both images look rather soft, but then so is the original.
Perhaps, the AI Gigapixel shot (on the right, below) looks marginally sharper in places, especially where there are lines on the print. I desaturated both images and added to both a very little contrast, as the original scan was deliberately slightly flat.
I zoomed in to both images and could see that, around edges, the AI Gigapixel upsized version did look sharper, but the software had created a fine double line around the edge which, when I added some high pass sharpening, created a very ugly artefact. The more edge contrast, the more artefact. The Photoshop version, though a tiny bit less sharp looking, was smoother in transition at the edges and a little high pass sharpening did not cause too much in the way of artefacts. In other words, AI Gigapixel seems to be adding more sharpening during the upsizing process than does Photoshop. Also there was a significant artefact in the left eye in the AI Gigapixel version, which had produced an odd looking “sharpish blocky” effect in the eye.
I decided to use the Photoshop version for my restoration, which I improved by repairing damaged parts of the image. Finally, I added a little noise reduction and some high pass sharpening. Below is a comparison of before/after.
Comparison before/after
Close up of finished image
Last of all, here is a crop from the finished photograph. I actually downsized it a bit at the end and it will now print at 16.5 inches high at 360 ppi.
Conclusion
There is no doubt that AI Gigapixel does a very effective job. It is different to Photoshop and the fact that it takes a much longer time to do the processing, possibly up to 10 times longer than Photoshop, to work its magic, it is obviously doing a lot of calculations.
I suspect that with a better original, ie sharper and cleaner, it would do a great job, but then so does Photoshop. Would I buy it – well no, I don’t have a lot of images I need to sample up (mostly I sample down) and I wasn’t blown away by it. If you are happy to accept some artefacts (and my experience is that many people don’t even see them), then AI Gigipixel could be for you. If you have the Photoshop subscription and are prepared to do your own careful sharpening after upsize, I don’t think AI Gigapixel adds that much to your toolbox.
Since my simple comparison, I have done more reading on the subject of upsizing and came across a quote which sums up how I feel about the Topaz Labs software:
It (AI Gigapixel) works well with natural, random, textures where it’s easy to accept the software’s best guess at what the details probably looked like. It’s a lot less effective on human faces and on man-made subjects where its tiny squirly polygons can start to look quite artificial. Sharp, but artificial.
http://lifeafterphotoshop.com/topaz-labs-ai-gigapixel-2-1-1-review/
Update
Update March 2020. If you don’t mind watching a 22 minute video with ad interruptions, here is a very interesting comparison of 7 upsizing softwares
