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I am working with a client who has sent me images taken with cell phones, most of them at 72 dpi, and wants them enlarged for a full-scale 24" x 60" print to canvas. The printer is telling me even with the LightRoom adjustments I have made, the quality is poor and pixelated. Is there any magic I can perform to make these pictures work?

Signed, Desperate and out of time.

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    let us test some magic. Insert one image file as downloadable link via some file cloud service. If you give a screenshot or include it as an uploaded file to the question, we cannot see what's the real situation. Please, an original, not one already mangled. – user287001 Sep 6 '17 at 16:30
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    If your printer is saying that the quality is poor, that suggests the problem is not only the dpi setting. There may be other issues. I can't tell you anything without seeing it - as @user287001 has said, preferably the original please. – Billy Kerr Sep 6 '17 at 16:40
  • 24 x 60 is way too big for a photo taken with a cellphone. Your printer is right. There are phones out there who can take pictures that just about have a large enough pixel count, but their sensors aren't good enough for the pictures to look good if printed at that size. – Janus Bahs Jacquet Sep 6 '17 at 17:07
  • It depends on expectations. Poor and pixelated in one person's view could be cool in another's opinion. It seem as if your client has been led to believe something reality is unable to deliver. – Stan Sep 6 '17 at 17:10
  • You cannot add resolution. Your source image needs to be very high quality and physically large, like it fills your screen when viewing it at normal size. I would be very cautious about scaling Any picture up. They look worse when they are stretched. To make big prints start with big source files. We all have to learn this lesson. – Webster Sep 6 '17 at 21:01
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No. There is no magic you can do.

I must explain something. 72 ppi does not mean anything regarding picture quality.

You can shot a photo using a 50,000 USD camera and it can be 72 ppi.

What you need to know is the total pixel dimension. Without this information there is no way to know the real issue here.

After knowing the real issue, one thing that you can do to minimize the obvious pixelation is to resample the image at 200% exact using bicubic or bicubic sharper. This will turn the squares into smaller ones by blurring a bit the overall image.

There are some programs that make a little tiny better job in some cases like Benvista PhotoZoom, and you can try it for free.

But the best thing you can do is talk to the client and tell them the images are not the best quality If that is the case.

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    > I must explain something. 72 ppi does not mean anything regarding picture quality. Absolutely. And just to clarify: the ppi or dpi is just an instruction to the printer about how many of the images dots/pixels to print per inch. It does not infer anything about the quality or size of the stored image. A 20,000 x 20,000 pixel image can be 10ppi. However, there's certainly a common-mistake in many workplaces of inferring that it does. – biscuitstack Sep 6 '17 at 20:01
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Hard to tell without seeing the actual picture, or having a talk with the printer. The picture isn't at 72DPI, 72DPI is a default DPI for any picture that has no indicated DPI (and a photo has no DPI, for a picture of a starry sky, a proper unit could be dots-per-megaparsec, and the same camera shooting through a microscope would produce pictures measured in dots per micrometer).

Now, a 24"x60" is not meant to be seen up close, especially printed on canvas. And an old rule of thumb in photography is that at normal viewing distance, you can't distinguish details smaller than 1/2000th of the image's diagonal. So you don't see pixels if they are smaller than 1/2000th of the diagonal (or if you have more than 2000 pixels in the diagonal). This in turn translates into a 3MPx image, 6MPx if you are conservative. Coincidentally, the first digital cameras deemed good enough by professional photographers were about 3MPx.

So, since cell phones currently feature cameras of 8Mpx or more, there should be no problem... but...

  • photos produced by cell phones cameras are usually outrageously post-processed to look good on the phone screen but look like pixel soup when seen up close,
  • people who take pictures with smartphones and consider that they can make nice printable pictures don't know much about photography and tend to make pictures of poor technical quality.

TL;DR: your printer may not be complaining about the size in pixels. And he could be worrying that your customer discovers the poor quality of his/her pictures once printed and thinks the problem is with the printer and not the picture.

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There IS some magic available. At least magic in the same sense as some isolated tribes could see the western technology when they met first time.

The magic I'm talking is image enlargener. I have used it uncounted times when one has had a screen resolution image and wanted it to be printed at the same or bigger size in centimeters as he watched it onscreen. Every time it had been the last resort, when there were no possiblities to get the real hires image soon enough. Every time the explanation was the same: "I was sure (or I have been told) that these images are good because they look out perfect onscreen"

If this is also your case, try the same magic. Image enlargeners can make a screen resolution image to same centimeter size or even larger image with print resolution. That happens without adding jaggines or making the images fuzzy.

Image enlargeners guess where there should be a sharp edge or a thin line and keep it narrow. Larger forms are made bigger by interpolating the missing intermediate pixels For example In good enlargener cat's whiskers do not get thicker altough you increase the pixel dimensions to 400%.

NOTE that the information is not increased. No program can guess a detail which were lost due too low resolution. A small dot which would have been visible, if the original photo was 2000 pixels wide, do not appear if you enlarge a 500 pixels wide photo to 2000 pixels.

The best enlargener I have met is ON1 Resize, ON1's product is old. It has been sold as "Genuine Fractals" and "Perfect Resize". ON1's product just was the one that didn't make cats whiskers thicker.

On1's software has premium prices. But there's also freeware. Smilla enlarger is well worth of checking.

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Increase scale in photoshop. The way photoshop scales bad images is better than a lot of other programs. Sure it will be blurry, however, that will look better than blocky pixels.

– Stan said "pixelated in one person's view could be cool in another's opinion."

Remember if your client is using this a sign from a distance it might not be so bad. The problem comes from viewing it up close. Which blurry always looks better unless it happens to be sprite artwork. Like for the new Sonic Mania game. enter image description here

So scale it please. If you do your printer will probably think the photo is a higher quality original because the file size and resolution will be higher with this technique too. You won't have to listen to them tell you its too low res to print... They do not always know a whole bunch of neat tricks like that and or do not want to be responsible for bad results. 1st hand experience. Have fun!

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    If your printer can't tell an upscaled poor-quality image, you need to find a better printer to work with. Printers are exactly the people, much more so than designers, who generally will—and should—know precisely what will and will not work in terms of resolution, colour depth, moiré, etc. – Janus Bahs Jacquet Sep 6 '17 at 18:30
  • It's not a question of whether they can tell the difference. It is his only option. His printer is just warning him it is too low res. Calm down and try to read everything first buddy. – Pixel Fixer Sep 6 '17 at 18:58
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    I did. You said, “So scale it please. If you do your printer will probably think the photo is a higher quality original because the file size and resolution will be higher…”; I'm saying that is not true with a decent printer. They will know perfectly well that this is a low-quality image that has been upscaled, and simple surface stats like file size and DPI won't fool them. Your answer is making printers sound like lumbering fools who only know the basics about images and won't know how to upscale them—I can assure you that is only true of printers you don't want to work with. – Janus Bahs Jacquet Sep 6 '17 at 19:04
  • I'm saying that obviously the printer that OP took this job to did not offer any suggestions to improve the print quality. So maybe he does need a better printer to work with. However, a lot of people prefer to do work with "drive thru" printers – Pixel Fixer Sep 6 '17 at 19:40
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    Perhaps—or perhaps the printer looked at it and judged that there was no way to bring the material they were given up to scratch for the job, and therefore sent it back with the message that better material was needed. That would likely mean it's actually a good printer. We can't really tell which it is. – Janus Bahs Jacquet Sep 6 '17 at 19:44

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