We have launched our free QR Code service http://gen-qrcode.com for a few days and the responses are indeed encouraging.
One of the important applications of QR Code is printing, in which the code images are required to be in much greater resolution. For a QR Code to be printed in 10″ X 10″ by offset printing, each side of the code needs to be at least 3,000px!
Enlarging directly a web-generated QR Code has a big disadvantage. Since it is in RGB color mode by default, during enlargement the interpolation process from the imaging software will insert gradation between black and white borderlines and soften the edges. It will result in lower accuracy during snapping. Keep in mind the following procedures you can, however, create large format QR Code images from web-generated ones with razor sharp quality:
1. Generate your QR Code in 300px or above
2. Download and import it into an imaging software such as photoshop or the free IrfanView
3. Convert the image to 1-bit image (Photoshop calls it bitmap, IrfanView calls it 2 Colors image, others may call it pure Black and White image)
4. Now you can enlarge by re-sampling it to as big as you need without losing the data bits
5. Convert the image back to RGB or CMYK color mode if you need to colorize it, or else it will be good to be printed or inserted into other artwork material
Easy, isn’t it?