This is a simple question that turns out to have both a very simple and a fairly complex answer.
The simple answer: you can’t. Not most of the time, and not with what you’re asking for.
The complex answer, of course, is: it depends.
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Unrealistic expectations
I get frustrated watching TV crime shows sometimes, mostly because I know too much. They frequently take significant liberties with what is and is not actually possible.
For example, a frequent scenario has a bunch of detectives looking at a blurry photo of a car in the distance, and the person in charge directs the resident computer guru to “enhance it”. Perhaps even more than once. Like magic, the blurry photo of the car in the distance gets crisper and crisper until the image can be magnified and the license plate easily made out. The cops identify the criminal and save the day.
It just doesn’t work that way.
At least not the magical “enhancement” they’re talking about. If a picture is blurry, it’s blurry. If a picture has low resolution, it has low resolution. Yes, there are “enhancements”, of a sort, but they all involve trading off other aspects of the image — typically decreasing the image fidelity in order to, say, increase contrast, change colors and the like.
But no enhancement will take a small, blurry image and turn it into a large, crisp one.
I mention that because, in essence, it’s exactly what you’re asking for.
Printing the puppy
Let’s use an example:
This cute puppy is a 200-pixel-wide image. On my screen, it measures approximately two inches across, meaning that my screen is, roughly, 100 dots per inch, or DPI.
Now, if I want to print that picture on an 8-1/2-inch-wide paper, using eight inches as the printable area, that means the printing process will need to make that picture four times wider (as well as four times higher).
Here’s a small portion of that image when magnified four times:
You can see the image is already starting to get a little blurry. It’s the same image as displayed above, just magnified
four times.
Sadly, we’re not done magnifying.
Most printers print at resolutions of at least 300 DPI, if not much, much higher. The net effect is that if you print an image that is less than that (say our 100 DPI image above), then the printer (or your printing software) must also magnify that image again. In our case, that’s an additional factor of three times.
Now you can really start to see the details of jpeg compression as well as the increased blurriness of the picture. Again, this is the same picture we started with. In fact, if you were to take a magnifying glass to that original on your screen, you’d likely see something very similar to this magnified version.
High fidelity puppy
The bottom line is that on-screen images rarely print in high fidelity.
There’s just no getting around the fact that you’re magnifying a small on-screen image and printing it on a device with higher inherent resolution.
Now, there’s one exception, but it depends entirely on how the web page was designed. And for reasons that will become clear, most web pages are not designed this way.
Here’s our puppy, once again:
If you’re on a slow internet connection, you may notice that this version of the picture was slower to display. It may also look slightly different than the same-sized image earlier in the article.
The first image in this article is a 200×217 pixel image. This image is a 1153×1249 pixel image, but I’ve instructed the browser to display it in a 200×217 rectangle. The browser automatically resized the very large image to fit in the very small hole.
I’ve set it up so that if you click on that image, you’ll see it in full resolution. Since the browser already had to download it to show you the smaller version, the larger version should display very quickly.
And this would be the exception. If an image on a web page is authored to use a high-resolution version downsized by the browser, then printing that image will likely use the high-resolution version, giving you a much, much better result:
In this case, the image still had to be enlarged to show the printed equivalent, but this time by a factor of two rather than 12.
The net result, of course, is a much sharper image when printed in a larger format.
I printed both in the course of preparing this article. I wish I could show them to you, but the example magnifications above definitely match the printed result. If anything, the printed version of the 200-pixel image is worse, as the printer’s magnification technique is apparently slightly different than I used to create the illustrations above.
High fidelity output requires high fidelity input
The bottom line is that for a high-resolution print resulting in a sharp, clear image, you need to begin with a high-resolution image.
Most web images are not high resolution in any sense. While 200 pixels wide might be very appropriate to view on screen, it’s nowhere near enough for a high-quality print… and there’s no way to get around that.
Do this
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Mrh, I wish this article had existed several months ago. I needed to explain to a tech-scared girlfriend why an image that looks good on the screen won’t look very good on paper. Oh, well.
There are apps such as Genuine Fractals and SmartScale that can increase the pixel densities with amazing results compared to the algorithms used in printers and image editors. Not to the extent depicted in the crime TV shows, of course.
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I had a friend point me at Genuine Fractals as well. (A
photoshop plugin,
http://www.ononesoftware.com/detail.php?prodLine_id=2 for
those so interested.) It’s definitely an improvement over
most stock enlargement algorithms, but still – you can only
go so far taking a 2×2 inch image and enlarging it to 8×8
:-). (As another friend pointed out, that’s a factor of 16
larger, if you measure surface area.)
Leo
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Here is something you can try if you have a scanner
1.) Print the image as is or save it to your hard disk and print using your image editing software and turn print actual size on. It’ll print a very small image on paper.
2.) Scan that image using a high DPI (above 800 dpi). Save it. Most software will allow you to scan only the picture if you print the whole page.
3.) Print that image and this time use scale to paper.
That should give you a better resolution in theory. Have not got a chance to try both as one but I have tried to do it separately, I have scanned a small image to a large dpi and it looks good. and print a webpage to paper and that looks as good as what’s in the webpage.
The downside is:
– It involves 3 steps.
– Since you have to print the small image on good paper to obtain good scan of the image you would waste a good quality paper
– The high res image would be >10MB with a slow PC this would be hard to process.
Great article. I was so disgusted when my husband ordered a copy of the picture of me and my kids out of the newspaper, and my head was cut off just above the eyes. At least now I have a better understanding why that happened.
You should have gone back to the newspaper and insisted on a new copy.
This article really doesn’t apply to your case since the paper has the high definition original. Bad cropping is just a failure on their part.
That’s a 10 year old comment being replied to, but … I find the resolution of photos actually printed in newspapers to be very poor, particularly when compared with their digital originals.
The method posted above by Famia, I’m sorry to say, isn’t correct in its statement that it “should give you a better resolution in theory”. That idea, in fact, is one of the most common mistakes people make regarding issues of digital images, DPI, and output size/resolution.
The basic problem with the method suggested is that it tries to create more detail than the original image contains — which, as Leo correctly points out in the article, is impossible. Printing out an image and scanning it at high DPI will be no more effective than simply adding false “resolution” by resizing the image in an editing program. Either method will result in a blocky, low-detail image, like the ones Leo showed in his article. In fact, the scanner method is slightly worse, since the scanner is forced to re-interpret the individual pixel dots that make up your image’s details.
Now, it’s true: sometimes this “worse” can appear better. Re-scanning introduces small variations in the image, which can lessen the boxy “checkerboard” appearance of the resulting scan — this may produce the appearance of a more detailed image. But all that’s been done is to “break up” the visible pixel grid-lines randomly, making them less obvious. You can get the same or better results by simply resizing the image in an app like the Gimp or Photoshop (producing “false” resolution), and then applying a slight blurring filter or other distortion effect to smooth out the image’s blockiness. There’s no benefit to printing and re-scanning an image that isn’t equally obtainable via software.
That’s not to say high-resolution scans aren’t useful for obtaining detailed images! Scanning even a tiny photo at very high DPI will produce an image with lots of (“true”) resolution. That’s because the source image CONTAINS at least that level of detail already. You can scan a photo at 800dpi and get great results, because actual (darkroom-)printed photographs have a much higher resolution, potentially into the thousands of DPI. (Slides, even more so — it’s possible to have a slide with detail that’s equivalent to 4000 or more DPI!) Even if the image is a digital print from a magazine or photo printer, the source DPI is in the hundreds.
Images for the screen/web, by contrast, are at “screen resolution” — only a few hundred total pixels in each dimension, because they’re meant to be displayed at roughly 96 DPI. So, Leo’s 200 pixel fox could be around half an inch wide or so, when printed “actual size” on a consumer 300-600dpi photo printer. And it still won’t produce a very detailed scan, no matter how high you set the resolution.
Hi Leo, if I send a photo from my phone/desktop to Whatsapp, SMS, E-mail, Facebook, etc., will it affect the quality of my original photo in any way?
Thanks.
I’m not sure about posting on Facebook, but sending a photo via email, Facebook Messenger etc. wouldn’t alter the quality.
Facebook messenger could. (Not saying they do, but they absolutely could.)
Thanks for the reply guys, but what i wanted to know is if the quality of the ORIGINAL could be changed in any way by sending them. As in the one I have stored in my phone or computer. Or is it just a copy without affecting the original when it gets compressed and sent?
The original is untouched. If you’re worried, make a copy first.
Got it, thanks Leo.
Leo: I don’t know how the question of printing from a website got reduced down to photo resolution but I have the problem you announced at the beginning, except image resolutions are not my concern.
I try to copy lots of webpages to my word processor (Libre Office Writer). I used to highlight the whole article and copy and paste. This was never successful. As you pointed out, all manner of extraneous objects showed up and they were all in endless boxes. I tried to delete the boxes which worked poorly. They use frames and boxes that must have been invented by the NSA because I have never seen anything like them before on my word processor. Some are eternal, resisting all massaging and deleting.
What I do now, is to abjure the global approach. Typically I am dealing with text interspersed with photos. I copy the text one block at a time and place it on my word processor. Then I do a COPY IMAGE on the following photo and copy that. Then the next text block and so on. This works immeasurably better than trying to capture it all at once.
The next tip is one I learned from Leo. Instead of pasting with CTRL-V, I use SHIFT-CTRL -V and choose the NO FORMATTING option. What an improvement over plain CTRL-V!
It’s a bit laborious and slow but it gets the job done.