# Overview
This article provides tips for things to consider when creating and using QR codes. QR codes have become ubiquitous because they are a flexible, resilient method of conveying information.
# QR Code Display
The most common display format for QR codes is black on a white background. This format ensures the highest contrast for a scanner or reader to reliably read the information embedded in the code. Sharp contrast is critical for a scanner to recognize code content quickly and is the safest option. With the importance of contrast in mind, QR codes can be produced in various colors. Putting QR codes over backgrounds or imagery can confuse a QR scanner reader and is not advisable.
# QR Code Size
The size of the QR code is also an important factor. One needs to consider the distance between the QR code and the QR scanner reader for the proper sizing. Although there is no technical minimum, the recommended minimum size for most smartphones should be at least 1 x 1 inch. Or 2.5 x 2.5 cm. Or 115 x 115 pixels (width and height) for close distance scanning. For use at greater distances (building, truck, TV screen), we recommended this basic formula: QR Code Minimum Size = Estimated Scanning Distance / 10. So a QR code should be 10x10 inches at an estimated distance of 100-inch scan.
# Encoded Data Quantity
The amount of data encoded in a QR code can increase the number of rows and columns within the code. A good analogy would be the number of words printed on a page: if you double the number of words, you need to reduce the size of the type, resulting in text that can be harder to read. Encoding large amounts of data can reduce the reliability and scannability of the QR code due to the reduction of the pixel size within the code.
One should avoid encoding large amounts of data and large distances due to the reduction in scanning reliability.
A helpful formula for calculating the amount of content and relative distance is: QR Code Minimum Size = Estimated Scanning Distance * the number of rows and columns / 250.
So if the approximate scanning distance is 10 inches (25 cm) and the number of rows in a QR Code is 63, then the QR Code size should be 2.5 x 2.5 inches (6.35 x 6.35 cm).
# QR Code Customization
Basic black and white QR codes can look like they are for official use only. When used without engagement in mind, they often blend in with other technical aspects of packaging or labeling.
Today, more companies are customizing QR codes by adding colors and logos to increase customer engagement. Often companies offer additional incentives to scan like “activate your warranty” or “scan for set up video” to help encourage use. It is essential to have higher correction levels (see Error Correction Levels) with added QR code design customization.
# Error Correction Levels
Error correction enables additional levels of readability of the data, even if there is distortion or customization to the QR code. It can also be helpful for applications where distortion, dirt, or damage may happen to the QR code. There are four levels of error correction:
- Level L: up to 7% error correction capability
- Level M: up to 15% error correction capability
- Level Q: up to 25% error correction capability
- Level H: up to 30% error correction capability
Raising the correction level improves reliability and adds to the density of the rows and columns within the QR code (see Encoded Data Quantity). The distance, design, and contrast must be considered for the proper error-correction level.
Generally, Levels Q or H should be chosen for use where environmental factors (dirt, scratches, wear-and-tear) may degrade image quality. Levels L and M are fine for general marketing purposes.
# Printing, Adhesives, and Durability
When placing QR codes on products or packaging materials, one should consider the environment and ware and-and-tear the QR code may be exposed to. Some products have strict regulatory/compliance standards that must be considered. Printing and attaching QR codes is described in detail under the ISO International Standard ISO 28219:2009 and must be considered for certain product applications (e.g., vehicles, tires, etc.).
# Testing
Lastly, your QR Codes should be tested before they are attached to products and materials for distribution. It is recommended that you have a testing process for QR Codes during the initial creation, printing and sampling over time for desired results. For QuickReg, QR Codes with a URL and 30-50 characters would be embedded. The site, https://www.hcidata.info/qr_code.php (opens new window), allows you to create QR Codes at different levels and sizes for testing. Once the QR Code is created, test your printers with desired sizes, then use the QR Code reader to ensure functionality. It is advisable to check with multiple manufacturers and models of QR Code readers (including mobile phone cameras). Sampling over time ensures the QR Code generator and printer is functioning correctly.