-
Paper size for printing photos
I was always thinking the normal print paper is A4, but when I try to use it to print borderless pictures. It turns out it should be US Letter. There is a slightly difference in size between US letter and A4. For normal printing with a border anyway, it doesn’t matter too much.
-
How to encrypt a file
We can use Zip with password but sometimes we just want to encrypt it or decrypt it directly. There is OpenPGP standard we can use. In Mac we can use https://www.gnupg.org/. Encryption with a password: