How Large Can I Print My Image?

Gerry van der Walt All Authors, Gerry 12 Comments

Do you print your images?

You should.  It’s awesome!

There is something really special about holding one of your own images.  Apart from completing the actual photographic process and ending up with a tangible product printing your images will add a whole new dimension to your photography.  Another (real) goal to shoot for.

One of the things that a lot of people struggle with is the sizing of a print and what size a digital image needs to be in order for it to print at an acceptable resolution.  This is a question I got asked a week or so ago and I know many people have struggled to get their head around this so let’s try and break it down.

Before we dig into some of the details around resolution and how cropping affects it check out this video in which I run you through the basics.

Resolution

The resolution of an image refers to the amount of pixels in that image.

For example, an image sized to 4,928 x 3,264 pixels will have a resolution of 16,084,992 pixels.

Yeah, that’s 16 million pixels or like we all refer to it, 16 megapixels.

You can try it at home.  Just take the dimensions of your image, multiply them with each other and there you have it.

Gerry van der Walt - Wild Eye Photography

You can find the dimensions of your image quite easily in Lightroom.

Check out the video to see how easy it is.

Cropping Affects Resolution

If you are not going to crop your images it’s going to be pretty easy to calculate the actual print sizes you will be able to print.  If you know your camera shoots, for example, 21 megapixels you can just calculate your maximum print size once off but, and it’s a very important but, cropping will influence the resolution of your image and subsequent maximum print size.

In the same way as we calculated the megapixels of the image above, watch what happens when I crop it in a little and then recalculate the megapixels of the images.

Gerry van der Walt - Wild Eye Photography

The new, cropped dimensions of the image is now 3,906 by 2,586 pixels which means the new size of the image is 10,100,916 pixels or 10,1 megapixels.  That’s a 6 megapixel, or 6 million pixels, reduction in resolution.

Or think about it this way.

By cropping the image I have reduced the amount of pixels – information in the frame – by around 30%.  It should start making sense that the less information you have to work with in your images the smaller the prints you will be able to produce.

Calculating Print Size

So now that you know how to calculate the resolution of an image, let’s see what size we will be able to print it in a very plain and simple manner.

It’s a generally excepted guideline that the resolution for print images should be 300dpi, or dots per inch, which then refers to the amount of information per square inch of the final print.  Let me know if you would like to delve into this in more details and we can look at it in another post but for now let’s keep it basic.

So, if we are not sitting with an image like the cropped one above – sized at 3,906 by 2,586 pixels – we simply divide each of the side by 300 to determine the final print size in inches.

Pixels / required resolution = final size in inches
3,906 pixels / 300 dpi  = 13.02 inches
2,586 pixels / 300 dpi = 8.62 inches

Therefore, if I wanted to print my image above at a resolution of 300dpi I would be looking at a print size of around 13 x 8.5 inches.

To get my print size in centimeters I would just multiply these measurements by 2.54 – standard conversion from inches to cm – giving me a print size of 33 x 22cm.

Some of the common print sizes in inches include:

  • 4 x 6
  • 5 x 7
  • 8 x1 0
  • 11 x 13
  • 16 x 20
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Can you see that by cropping you are not only reducing the amount of information in your images but you are also limiting the maximum size to which you can print your images?  Also, remember that there are ways in which you can upsize your images and other factors like acceptable viewing distance also plays a role in this but if you use the above as a guideline you should get decent results when you head out to print your images.

Hope that helps a bit but feel free to shout if you guys have any questions!

Until next time.

Gerry van der Walt 

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Comments 12

  1. Gary

    Hi Gerry.

    Nice article but what about large format printing?

    The distance between viewer and print also has a role. I recently got a print on glass 4 feet across at 150 ppi. The vendor was encouraging me to go bigger at 90 ppi.

    Up close you see the loss of pixels but viewed from a meter plus it looks awesome.

    The other aspect to this is digital enlargement via software. I have little experience of upscaling.

    Love to hear your views ….

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      Gerry

      Thanks for the questions Gary! Yes, large format does change things a bit.

      Firstly, I would definitely look at getting some upsizing software to bump the file size up a bit. I used to use Genuine Fractals but it has been replaced by Resize 9 which is apparently amazing. You can check it out here – http://www.ononesoftware.com/products/resize9/.

      Then, as you mention, acceptable viewing distance will come into play. I have heard of resolutions of as low as 50 LPI (lines per inch used for large banners etc) but this will all depend on what you are printing, the medium you are printing on and how far, on average, your viewer will be from the print. I would personally not go lower than about 90 dpi resolution but then we will be talking about a massive print!

      Hope that helps but shout if you have more questions. 🙂

  2. Jacques Blignaut

    Hi Gerry, thanks for this. This was very helpful. What I still not sure how this whole dpi thing works. It will be great if you could do a blog on this if it is possible. I am currently sitting in a situation that I want to print a photo of mine and I was not sure if I could blow this up to roughly A3 size.Ok, I want to go through an example with you. I have a photo with the following dimensions. 3053×2044 – this is then 6,2MP and I downloaded it at 1000dpi. So as I understand it correctly, I can blow this only up to 3.05inch x 2.04inch? Wow that is small. So, if I drop this down to 300dpi, I will be able to blow it up to 10.18inch x 6.81 inch which will get me closer A3 then. I always thought that the more dpi’s the better the quality. What format does one then use to take in for print. In this example with 1000dpi, I stored it in tiff which is about 37mb file. Will the 300dpi be a bigger file? So I am very surprised to find out know that one will not get more than 3×2 inch. So I am glad I have not taken my photo in yet. It would have been a waste of money. So if there is any other thoughts around this to explain will be great.

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      Gerry

      Hi Jacques. Thanks a lot for all the info!

      Off the bat, I have no doubt that your image, at 6MP will print perfectly at A3 if you go with 300dpi. With the way that printers render the pixels from your image into printed information it is very unlikely that you will see a difference between a 300dpi print and a 1000dpi print except for the ‘suggested’ size. If you feel you need more print size you could downgrade your dpi to 240, then 150. FYI, most newspapers are printed at a resolution of 150dpi. 🙂

      With regards to file type I would normally, unless it’s a specific print job or the printer requests it as such, supply a JPEG. I will work the file in Lightroom, and Photoshop as and when needed, and then export to my final JPEG. With regards to file size, I must be honest I don’t know. I don’t personally pay too much attention to file size and rather make sure that I get the resolution and image quality right. 🙂

      Hope that helps but please shout if you would like to discuss more!

      1. Jacques Blignaut

        Thanks Gerry for your reply. I have this thing in my mind that the bigger the file the better the printing quality. What I learned is that the resolutions is the most important. Thanks again.

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  3. Sandi

    Thanks Gerry. This information helped a lot. I just went to Yosemite National Park and have a great print of El Capitan I want to enlarge.. The resolution, according to your post calculations, is perfect for the size I want to enlarge my print for our living room wall. Thanks for helping me get the measurements down with your fine explanation. 🙂

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