Re: printing QR-codes on labels with 300dpi label printers with LaTeX
On 10/3/24 15:39, Max Nikulin wrote:
From your earlier message I count approximately 1000px for 5in (125 
mm) barcode. If it is 1:1 to ~200dpi then it is incompatible with 
300dpi printers, so it may be a reason why your proposal to the post 
office was rejected. If it is 500 black or white lines and each one 
occupies 2 printer dots then 300dpi image of the same size has 3 dots 
per line. (Sorry, I am unsure concerning "module" term.) You should be 
able to rasterize PDF files to 600dpi (2x factor) and downsample them 
by 1/3 keeping lines sharp.
In barcodes such as Code-128 a module is 12 'slots' which at minimum is 
one pixel per slot or 12 pixels. Code-128 has over 100 character 
encodings in a module.
So code 128 on a 203dpi printer 12 * characters / 8 mm e.g. for 40 
characters it's 12*40/8 = 60mm. 2 pixels per module make it 120mm. 3 
pixels per module make it 180mm so too big for mailing labels.
As for my post office, their barcodes do not match 300dpi or 600dpi. 
They are scaled at about 75-80% of what they should be. I'm really 
surprised they work. I can only guess most people use 1200dpi.
Thermal labels are the way to go as they stick really well and resist 
water. They are also *cheap*. around 1-2 cents in bulk for 100x150 . 
Plastic envelope and laser printed label will cost 10-20c. A self 
adhesive laser label is getting on to 50c.
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