I would like to make postcards. Is the paper suitable for writing on the back by hand? Or is there a paper variant that is already printed on the back as a postcard?
Regarding the first question: You can write on the back of the printed photo with a biro, felt-tip pen, etc. without any problems. I use the "paper" offered by Canon for the Selphy printer. BUT please note: On the said reverse side the word "Canon" is written at least 35 times, greyed out but clearly visible!!!!. This obstructive circumstance could be circumvented by sticking on an A4 label paper (self-adhesive) cut to A6 size.
Regarding question 2: No knowledge!