Whenever and How to Upsample an Image

Upsampling is a tool in most post-processing software that allows you to raise an image’s resolution right after taking it. Upsampling allows you to boost, say, a 24 megapixel image to forty eight megapixels, 96 megapixels, or 240 megapixels! But doing this doesn’t mean you’re in fact capturing more detail.

This article covers all you need to know about upsampling, including the best upsampling software today plus my recommendation for just how much to upsample a photo.  

Table associated with Contents

What Is Upsampling?

Upsampling is a tool in post-production software to improve resolution. It’s most common in photography and graphic style to increase the resolution of the image, but it can also be used to boost the resolution of a video clip file (say, from 360p to 720p) or any other visual data.

However , upsampling isn’t a magic bullet. A 12 megapixel image will never contain just as much detail as a comparable 48 megapixel image no matter how a lot you upsample it or what algorithms you use. Even when it could, you could just upsample the 48 megapixel image by a corresponding amount and still come out ahead!

Rather, upsampling is a fairly niche tool to solve a few specific problems that you may encounter occasionally when you work with pictures. It’s not something meant to be utilized all the time; doing so would only take up space on your hard drive without meaningfully improving the quality of your images.

When to Upsample an Image

You will find two major situations where upsampling an image is a good idea. The foremost is when you’re working with a digital file that is extremely little, maybe just a few hundred pixels across. The second is when you’re printing an image and want to prevent pixelation in the details. I’ll go through both of those beneath.

1 . Low Resolution Images

If you find tiny image online (public domain hopefully) and you want to put it in a presentation or send to someone, you might be wondering if you can use an upsampling algorithm to increase its degree of detail.

Generally, the answer is no – there is no possible way to increase an image’s detail if it was not there in the first place. But what you can do is decrease its pixilation . Rather than jagged “stair step” associated with pixels along a diagonal line, upsampling can give you a smoother edge.

This is a typical example scenario of what you’d have the ability to do with upsampling on a low resolution PNG (click to see larger):

How to Upsample an image PNG Bicubic Smoother

As you can see, it’s not an excellent improvement, but the second image does look a bit better. The pixellation has been replaced with some general softness, which I find preferable.

Although this isn’t the best upsampling algorithm that exists today, it’s representative of a typical process (in this case, Photoshop’s “bicubic smoother” enlargement). There are several artificial intelligence upsampling algorithms can do better – I’ll get to those in a minute – but there’s still no substitute for a high quality starting image.

2 . Printing Pictures

Together similar lines, pixellation can show up if you try to make a large print in pictures. Even with a fairly high resolution messfühler like a 24 megapixel DIGITAL SLR or mirrorless camera, substantial print sizes (in the range of 24×36 inches plus up) can look a little pixellated upon close examination.

Just like prior to, upsampling doesn’t actually add more details to a photo, although some of the newer artificial intelligence algorithms come close. Instead, upsampling can minimize pixellation and replace it having a bit of a blurriness instead.

Here’s a (very, very extreme) crop from the 24 megapixel image showing a palm leaf. Note how the detail looks after and before upsampling using the same “bicubic smoother” algorithm:

How to Upsample a Photo

It didn’t specifically get sharper, but it do get less pixellated.

Best Upsampling Algorithms Today

If you’re going to upsample, not all algorithms or software options are equally great. I have no allegiance to any particular company, but there is certainly one general class of upsampling algorithms that is way ahead of the competition these days: synthetic intelligence upsampling.

As far as I know, AI upsampling is available in five different software program options at the moment: Adobe Lightroom, Adobe Photoshop, Adobe Digital camera Raw (which is element of Photoshop), Topaz Gigapixel, Pixelmator Pro, and Bigjpg. We haven’t tried Bigjpg but the other five all function similarly well as one an additional. (See my review of Photoshop Super Resolution for a few comparisons).

In the image below, you can see the difference between the traditional “bicubic smoother” upsampling algorithm versus an AI upsampler:

Bicubic Smoother vs Super Resolution Photoshop

The difference is even better in the vector image, even though this is a best-case scenario for that AI upsampler because it’s just some lines and curves:

Bicubic Smoother vs AI Upsampling

If you don’t have Photoshop, Topaz Gigapixel, or any of these software options, you may not be able to use AI upsampling. But there are plenty of free of charge software options which can upsample your photos, too, plus a few websites. Just Google around and you’ll discover it that works. All of the free ones use similar algorithms as one another – about such as Bicubic Smoother – and so they get the job done if you just need some basic upsampling.

How Much to Upsample?

The typical goal of upsampling, at least for a print, is to remove low-level pixelation. So , it is worth asking how much pixellation we can even see to begin with – in other words, how many pixels per inch (PPI) our eyes can resolve.

In doing research for this article, I found answers that ranged from about six hundred PPI ( resource here ) in order to 876 PPI ( source here ). Anecdotally, I can notice small differences between a six hundred PPI print and designs with lower pixel densities if placed side by side, plus some people definitely have better eyes than I do. However , this assumes you’re staring at the print as closely as your eye can focus rather than standing back from it because you’d usually do.

The typical standard meant for printing is 300 PPI, and while you may think that sounds low compared to 600 or even 876, it’s hardly a bad standard and doesn’t give prints that look pixellated. But just to be on the safe side, when I am printing on a paper with low texture, I usually upsample to at least 400 PPI instead and occasionally a bit higher. It’s hardly a difference worth worrying about, when you’re already upsampling, there’s not much harm in aiming above the generally recognized 300 PPI.

Here’s a chart of some common print sizes with a 2×3 aspect percentage, plus the image resolution that will result in 400 PPI designs at each size:

Printing Size (Inches) Print Size (cm)* Resolution Needed for four hundred PPI Megapixels Needed for 400 PPI
4×6 10×15 1600×2400 several. 8 megapixels
8×12 20×30 3200×4800 fifteen. 4 megapixels
10×15 24×36 4000×6000 24 megapixels
12×18 30×45 4800×7200 34. 6 megapixels
16×24 40×60 6400×9600 61. 4 megapixels
20×30 50×75 8000×12, 000 96 megapixels
24×36 60×90 9600×14, 400 138 megapixels
30×45 76×114 12, 000×18, 000 216 megapixels
40×60 100×150 16, 000×24, 000 384 megapixels

If these seem like remarkably high resolutions needed for fundamental print sizes, remember that the particular figures above aren’t always meant to be your camera’s resolution, but your resolution post upsampling .

An AI upsampling algorithm like that of Photoshop, Lightroom, or Topaz Gigapixel will quadruple your photo’s original resolution without main issues. Again, it does not really add any more details, but it does reduce pixellation and give a cleaner print out. So , whatever resolution your camera has, multiply it by four to see your equivalent on the chart above.

For example , if you’re shooting with a 24 mp sensor, you’ll end up with the 96 megapixel image after the usual upsampling. Per the chart above, that’s a good fit for a 20×30 print or smaller. If you don’t need to stare on the print from a few inches away – which, let us be honest, is almost by no means needed on such a big print – you can drive it up to a 24×36 printing and more. This article isn’t a treatise on how large you can print, just whether you need to upsample before printing. Lots of 8-megapixel and 12-megapixel pictures have been printed on billboards and look great, so don’t let the numbers above end you.

That said, smaller prints (like 12×18 in the case of 24 megapixels) are going to look crisper than a large enlargement, even if you used the greatest upsampling algorithm in the world. It all depends on how strict your standards are and how closely you’re viewing the print.

How to Upsample an Image

The actual process of upsampling couldn’t be easier. You weight the image into your post-processing software and find the upsampling or even image size tool. Unless you already know where it is in your software, a thirty-second Search should answer that. In Photoshop, for example , the AI algorithm is found in Image > Image Size > Resample > Preserve Details 2 . 0. In Adobe Digital camera Raw, you right click on the image and click “Enhance. ” In Lightroom, you click on the image and go to Photo > Enhance in the top menu.

Once you’ve done that, it’s a simple matter of inputting your desired resolution (if that’s even an alternative; in Camera Raw and Lightroom, it just upsamples 4x automatically) and that’s it. All that you need to do now could be save your image to be published or sent wherever you would like.

Bottom line

Upsampling doesn’t add any more detail than you originally captured – it just reinterprets your image to reduce pixellation. Even in the best of instances, with a high-quality AI criteria, the image won’t look because clean as a high resolution first.

Also, upsampling doesn’t work well unless you taken a pin-sharp photo to begin with, with minimum blur and minimal sound . So , make that the priority! The difference between a pointy versus blurry photo is certainly far greater than the difference among an upsampled versus non-upsampled photo.

Still, in certain cases, upsampling can produce a noticeable difference. Any time that you make large prints (or small/medium prints from a reduced resolution image), I recommend upsampling before sending the image away from to the lab or home printer. Same if you’re aiming to improve the detail in a low-resolution image online for a display.

Even though the variations may not be drastic, you’ll nevertheless get some more detail and less pixelation by upsampling compared to using the original. For a technique that requires very little effort, it’s hard to ask for more than that.

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