webapp rec – Print a barcode from the web, its length has added a bit

I've created a code 128 (8834635) from the web (php) and also the code I've created from C #. I have tried to print from C #, which corresponds to 100% visualization of the print. But I printed from the web the length of it added a bit, I tried to take pictures while watching print (web and c #) compared to photoshop the same. Why the word Web is badly printed (I tried chrome and firefox). I hope everyone will support me to understand better. Thank you