Resolution Matters: What is DPI and why do I need to know?

Picture this: you’ve been looking at the numbers for your company and feel like you could benefit from some advertising. There’s a photo on your website you’ve always liked and know that you definitely want it in this ad. So, you come up with a market to target, buy a full-page space in a magazine, think of a catchy campaign, write all the copy, and ship the concept off to your in-house design team to turn it into a reality. The next day, your art director sends you a very polite email explaining the picture you took so much care in choosing is too low PPI and that they need a higher resolution photo in order to proceed. After carefully reading the email a couple times over, you think to yourself, “what the #$@!X& is PPI?”. Well, worry no more, because I am here to help you understand why PPI is so important and how it can affect the impact of your ad.

Let’s start simple, what exactly is PPI?
It stands for pixels per inch and is meant to represent a photo’s resolution. A low PPI means there are less pixels per inch, so small details in your photo may not be crisp when the photo is blown up.

Here are three photos of three different resolutions, can you tell the difference?

If the answer was “not really” then you would be right! At this size it is nearly impossible to tell the difference, but that’s because we are looking at the image minimized on a screen. If you were to use this image in a full-page ad, you would make these images quite a bit larger, and that is where we really see the difference. Look at these images again when we zoom in.

Now the image on the left looks less clear than the other two. This is because the less pixels per inch, the smaller the image. Making a smaller image fit a larger space causes the lost details to appear obvious and makes the image look blurry.

Ok, I guess I see the difference now, but what does that mean for me?
When it comes to resolution, you really need to be the most careful around print. Since many times your computer screen is smaller than the ad will be printed, many people fall into the trap of not catching an image’s low resolution until it’s too late. In order to help your design team, make the most attractive print ad they can, they need high resolution photos to work with. That means checking a photo’s resolution before sending it to be used in print materials. You can check the image size, and if its width or height are below 1000 pixels, then it is most likely too small for print.

You also need to consider the contents of the photo. If the photo itself is large, but the focus of the photo is small within it, then it may not be usable. You have to consider when it’s implemented into the ad, the designers may have to zoom in quite a bit in order to make the photo work with the design. If you aren’t quite sure whether or not a photo will work, then don’t be afraid to bring it to your design team and ask whether or not that is the case.

Why would anyone make photos low resolution?
When a photo is exported at a large resolution it is making the photo itself large, that means more memory needs to be used to store it. This is great for print, but not so great for web. When posting an image on your website or social media you want it to be smaller so it takes up less space and loads quickly for the user. Large images take longer to load and can affect your entire site’s speed. This is also why it’s not usually a good idea to download photos from the internet or Facebook to use on your site or for print.

So, I need to provide my team with only large photos?
Within reason! In most cases photos that are above 1000px but below 5000px are going to be fine to use. Don’t send giant 10,000px-by-10,000px photos to your design team because it is unlikely they will ever need a photo that large and it will just take up unnecessary space.

There you go! Hopefully, that helps you understand photo resolution a little bit better. Now go on and pick a high resolution photo to send off to your design team!

Meagan McCall is a graphic designer at Imagine Communications.

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