Not arcade related just need some info, please help me.

[abispac]

Thanks for reading, i have a credential size picture of my mother when she was young and she looks gorgeus, now i been thinking for a while that i want to make that picture into a 50 inch paint, now i got the guy whos got the right printer to use a canvas lile material. ive seen pictures printed in this kind of material and they look veri nice, so my main question is for all of you experts:
What do i need to do to the picture so i can upscale the picture and it dosnt look pixelated?
The picture its black and white and if i upscale the picture up to a 14 inch it looks just fine, but more then that size its starts to get pixelated. Thanks for any advice. And pardon my bad english.

[wol-nz]

That is one of the unfortunate side effects when 'up-scaling' a picture.
If the original picture or scan isn't 'of quality' then the picture will lose quality as you enlarge it. (can't do anything about that as the picture can't magically put more pixels or colour into a picture)

At best my opinion would be to place a soft blur over and see if that smooths the pixelated and jaggy edges.