Read and generate QR codes on the iPhone – how it works

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Since the update to iOS 11, the iPhone can recognize and evaluate QR codes without any external help. We’ll show you how it works in step-by-step workshops.

Handling QR codes on iPhone and iPad is basically not new. Since iOS 11, the camera app now also recognizes QR codes in the preview image automatically. Reason enough for us to introduce the function in more detail and also to show you what you can do with the square pixel codes or how you create them yourself.

One code for all cases

You probably got used to the different pixel and barcodes on packaging, tickets and all sorts of things that you barely notice. The square QR codes can be found primarily in advertising, on information material or in magazines. They contain encrypted information that can be read in and decoded with a suitable scanner. Of course, a smartphone with a camera is ideal for this.

The most common application is certainly the storage of a URL. The iPhone reads the code and opens the associated website. The QR code creates a connection from paper to the digital world, a printed link, as it were – simply hold the camera on it instead of touching.

QR codes can also contain many other information, such as contact data, appointments, GPS Coordinates or just short texts. Even prefabricated SMS and telephone numbers, which you only have to activate after reading in, or WLAN access data – very convenient for guest WLAN – can be accommodated here.

Power consumption

As soon as you activate the camera, it searches for QR codes, which consumes power. It is therefore a good idea to turn this feature off when you do not need it.

The iOS 11 camera app provides relatively simple support for QR codes. This applies to both the operation and the possibilities. It recognizes a QR code in the viewfinder image, analyzes the content and then offers to pass it on to the appropriate app. That was it already. An already taken photo can no longer be examined for on-board QR codes. Also, iOS can not generate the useful pixel codes. You will need to use an additional app or website to do this.

QR Codes: Size and Color

The information is encoded as a pattern of small squares when the QR code is generated. The information content can be influenced by the number of pixels. A QR code has a redundancy that can be selected in several stages, that is, in complex codes with many pixels, the information is inserted several times. If any part of the code is covered or damaged, the scanner attempts to reconstruct the data from the rest. The greater the redundancy, the more the QR code may be missing. For example, a company logo can be placed in the middle of a QR code. Color and size of the QR code only play a role indirectly. You decide if the camera recognizes the code at all. You need sufficient contrast between the pixels and the background. Whether black on white or dark on light blue plays basically no role. Even multiple colors are possible, as long as both levels are clearly distinguishable in terms of brightness.

When saving the code you should avoid anything that affects the sharpness: This also includes the JPEG format, because of that Compression can produce annoying artifacts. More suitable are PNG or TIFF.

If you want to output the code on a color printer, make it as pure black as possible (without color addition). This may be a bit paler, but provides sharper contours. Average redundancy is usually sufficient. If the later size is not fixed yet, a scalable vector format like SVG is a good choice.

For a fixed size use at least 150 dpi. Codes with graphical elements should have 300 dpi and high redundancy.

Generate QR codes

There are several apps in the store that can generate QR codes. Our favorite is Qrafter. It may not have the most elegant interface, but is very versatile in reading and generating codes. The app is free. The pro package for 3.49 euros makes the app ad-free and offers some additional professional features.

A simple and free method for generating QR codes with Mac and PC is the website goqr.me/de. Here you first select the type of content and then define redundancy, size and color during the download.

Alternative

Those who frequently access QR codes will quickly learn to appreciate a more versatile app like Qrafter. It supports a lot of data types, can analyze photos and provides an archive of scanned codes.

Workshop: How to Read QR Codes with the iPhone Camera

Workshop: How to Create Your Own QR Codes Using the App Qrafter

Read and generate QR codes on iPhone – how it works (Picture: Screenshot)

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