Sometimes, I am somewhat dissatisfied with the size of my digital photographs. The simplest way to improve (after the fact) is to run any Photoshop-like program, and apply a resampling (resize) preferably with the Lanczos method, in order to get 2x or 3x or 4x more pixels. It is fast and efficient, but it usually generates a slightly blurry but bigger picture. If the target is a large format print that could be watched from a short distance, or for something like printing on a very large canvas, I should have more details in the picture (more than what was initially collected by the camera). The image is still too small.

The other approach would be to use a software tool like Topaz Photo AI or the all-new Adobe Photoshop “Image Enhancer AI”. Those are Pro tools (“Pro” means “expensive”): Topaz costs 199$, its competition often relies on monthly subscriptions. For a normal guy (who only needs it a few times per year, at most), this is not applicable.

Why not look toward (free) Open Source tools? Fortunately, some are existing.

And I added another constraint: I want it to run on my own PC (no cloud resources and/or cloud subscription like what StableDiffusion requires).

The general idea

For a few months, I have been impressed by the multitude of Artificial Intelligence solutions (Didn’t you hear about something named ChatGPT?) and not only to generate human-readable text. Tools like StableDiffusion, Dall-E, or Midjourney generate spectacular pictures from a textual description (a prompt). But they often include a mechanism to extend their text-to-image activity to a much larger scale (usually they produce small pictures to sparingly use computer resources).

My solution – in details

I won’t detail the steps taken to reach that solution. But here it is.

One strong PC, with two options/directions that could be imagined.

• A powerful graphic/video card (not always, but often based on nVidia GPU).
• A super-powerful PC with (most critical) a lot of memory.

In my own case, I chose:

• i9-13900K (with a good AiO liquid cooler, because this beast can heat up quite quickly when running 100%),
• 64 gigabytes of DDR4-DRAM memory (you will hear that this is the limiting factor for the image size).

But, you could work with a smaller CPU (with a lot of patience), or a Mac computer.

Nobody would claim this is a cheap PC, but it definitely works reasonably well.

EasyDiffusion installation steps

EasyDiffusion is a free version of a tool very similar to StableDiffusion. You may install it on your PC, and it will run either on the CPU or on the video card.

• Download the installation program from the EasyDiffusion home page (according to your needs, you’ll choose the binary for Windows, Linux, or Mac).
• Follow the installation steps from the page, don’t worry about changing any option right now. You will need some patience (it goes and download additional models and other packages, it will build some of the files during the installation).
• Run the program from the Windows “Start” menu. This will open a Command window to run a few background things (no need to even look at this), then a browser window giving access to the EasyDiffusion user interface.

• For the first configuration, I would recommend clicking at the top of the page on “Settings” and selecting the following program settings:
  • Auto-save Images: YES
  • Save Location: select the appropriate directory to save your creations.
  • Open browser on startup: YES
  • GPU memory usage: High (with 64 GB of DRAM, you want to use it all or as much as possible).
  • Use CPU (not GPU): YES
  • Beta channel: NO.

Create a text file whose name should be YR_MoreResolutions.plugin.js with the following text contents:

// ==UserScript==
// @name         Ski-SDUI-MoreResolutions
// @version      0.1-YR
// @description  More Resolution Options
// @author       Super.Skirv, JeLuF, YR
// ==/UserScript==

(function() {

	options="";
	for(i=6; i<=32; i++) {
		options += '<option value="' + (64*i) + '">' + (64*i) + '</option>';
	}
    options += '<option value="' + 3072 + '">' + 3072 + '</option>';
    options += '<option value="' + 4096 + '">' + 4096 + '</option>';
    options += '<option value="' + 4640 + '">' + 4640 + '</option>';
    options += '<option value="' + 6960 + '">' + 6960 + '</option>';
    options += '<option value="' + 8192 + '">' + 8192 + '</option>';
    document.getElementById('width').innerHTML = options;
    document.getElementById('height').innerHTML = options;

})();

• Install the plugin, by copying the YR_MoreResolutions.plugin.js file in the C:\EasyDiffusion\plugins\ui directory.

Operation and typical use

When arriving at the EasyDiffusion page in your browser, you will need to feed it with a source picture to enlarge and the right upscaling options:

• Choose the source image with the “Browse” button.
• Custom VAE: None
• Image size: 3072 (width) by 2048 (height) – for 64 gigabytes of DRAM.
  • This parameter is dictated by:
    • The need to work on an image as large as possible
    • The memory size limitation. If you have only 16 gigabytes of DRAM memory, you will need to reduce these parameters each in a ratio of 2: 1536 by 1024. But you can explore the optimum for your configuration.
  • Swap the parameters if the image is in portrait (vertical) orientation.
• Inference steps: 50 (this has practically no influence, you can leave the default value)
• Prompt strength: 0 (This is the critical value: It will ensure that EasyDiffusion AI never tries generating a new artificial image from the prompt text, but concentrates on the upscaling job).
• Output format: choose the right file format for you.
• Show a live preview: NO
• Scale up by 4x with RealESRGAN_x4plus (Avoid RealESRGAN_4xplus_anime_6B which is totally not for photography)
• The prompt (at the top of the page), and the Seed value (in “image settings”) are not used, except when naming the output file.

If you don’t have enough memory, you can always reduce the “Image size” or you get a message like the following:

The message tells you what memory size it tried to allocate/reserve. This will guide you when reducing the “Image size”.

If you are correctly configured, after a few minutes, you will see the result like in:

Notice: the new resolution is now 12288 x 8192 pixels (we left from 6960 x 4640 pixels, to reach no less than 100 mega-pixels). But, above all, the Artificial Intelligence (of the ESRGAN network) determined new pixels not only interpolated but imagined as complementary to the existing ones and totally credible.

In the picture used for this example, don’t spend time checking the blurred background. But take a look at the fine details in the structure of the dragonfly wings. It may not be perfect (from the professional entomologist’s point of view, there are anatomy errors), but the ribs/veins and the light reflections are very natural-looking, even in areas where they are only half-drawn or half-blurred. The same remark applied to the eyes and antennas of the dragonfly.

On the opposite, don’t even believe the proposal from the software: It’s no use clicking the button to upscale again to 20032 x 13376; You already reached the maximum size allowed by the available memory. You can’t go further with only 64 GB.

If you want to check the results, I made the files available:

• Original
• Upscaled x4

It is most visible when shooting long exposures and the strategy used by most photo cameras is simply to shoot an additional black picture(without opening the shutter) just after the photo you wanted to find the hot pixels and remove/subtract them from the original photo. This is observable as a relatively long computation after a long exposure photo.

Sample kindly provided by Dan Thorberg.

It takes time in the field and it uses up the camera electrical energy. So, here is a small tool that allow to transfer this operation toward the studio PC: PixelFixer.

The list of photo cameras this tool is compatible with contains a lot of cameras from Nikon, Canon, Pentax and Leica. No Sony I know of (they are left with the in-camera option that works well too).

Téléchargement gratuit de PixelFixer.

Since 2009, we can consider that the race for more pixels is over. All camera manufacturers decided more or less to go easy on resolution: Over 12-15 MP, you can easily print an A4 or Letter-size print in top quality. Most photographers will never need more. So, why go over 20 MP?

Most manufacturers followed the lead of Olympus and Nikon trying to enlarge the pixels in order to ensure they collect more light and this leads to a higher level of sensitivity as measured by the ISO standard. This is good, because this means that our pictures are going to be better and better, not only uselessly finer and finer. Moreover, maximum ISO sensitivity becomes a relatively good proxy for image quality.

However, there is a slippery slope here. It has already been observed in some Point-and-Shoot compact photo cameras: A manufacturer may be tempted to push a maximum ISO level to ridiculously stratospheric altitudes. It’s not only because you P&S camera can do ISO 1600, that its pictures are still usable (noise cancellation algorithms may be so energetic that most of the details are blurred in the process).

Usually, in the D-SLR market we do not see this happening too often, but there is a risk. With Canon and Nikon leading the race with (pro) cameras over ISO 100,000, we already see figures that are amazingly high and images that are already quite bad (for a pro).

Don’t get me wrong! I’m quite happy to see that technology will soon be allowing us to shoot pictures in darkness without using a flash. But those two very serious camera manufacturers have obviously been racing to reach an ISO landmark. Some others, maybe less able, will reach it not only with barely usable photos, but with really unacceptable pictures. Then, it would become a fruitless race again, with figures creeping into the fact sheets and a real-life comparison will be ever more critical.

For me, the Canon EOS 1D Mk IV and Nikon D3s are useful because they produce absolutely great photos at ISO 32,800, not just because they can collect a barely informational document at ISO 102,400. Let’s be attentive with the present products from Canon and Nikon and the future cameras from all the photo camera manufacturers.

We should still be photographers and not just number-seeking blind consumers. I hope we are.