But what if you want the image to be bigger? If you simply stretch the qr-code it will probably look horrible when printed. This is because the codes as they appear on the screen are only 150 x 150 pixels and the software has stretched the image using rules that wirk for photographs, but are not so good for graphics.
We did think of adding some buttons to allow you to download the image in some larger sizes before we realised that there is an easy way to scale the image to any size you need.
- Paste the qr-code into gimp. (Our favorite free, open source image editor).
- Select image > scale image.
- Set interpolation to none. Interpolation sets the rules used to scale the image.
- Set the dpi.
- For viewing on screen use 72 dpi.
- For ordinary colour printing use 150dpi.
- For high resolution printing use 600 dpi.
- If you are a professional printer you will probably smugly say you use 1200 dpi or higher.
- Set the image to the size you want. Happily you can mix imperial and metric units here, but you will want to keep the width and height equal.
- Click scale.
- Save the image as a TIFF, PNG or other "non lossy" format otherwise it will look fuzzy.
- Print and enjoy.