Printing other people's pics

[Aubrey]

I feel pretty confident (thx to D) when I'm printing my own work. I know what my camera can do and I understand my own edits. Take all that away and I freeze up! I got hired by a custom home builder to shoot different houses that they've completed. Cool, no prob. Then they send me a dropbox of a ton of houses someone shot before me. Some are cell phone pics at 72ppi so I wont be using those. Some were shot on a Canon EOS 6D. Nice camera but I'm a Nikon girl. Some of the pics are at 240ppi, others at 300ppi. They are all jpgs and the file info says they were edited in LR. 

They want me to take the best shots and print a ton on acrylic then have me mount them all over their brand new office. No pressure there.....only hundreds of people will be seeing all the big prints! Sigh. 

D-I have read your articles about "as long as it's in focus you can print on an 18 wheeler truck". Just to calm my nerves can you tell me what is the minimum file size I should even consider printing? Some are <10MB. I need to be able to print on acrylic from medium sizes up to 60". Please help a girl out and give me a basic break down of "only print files with these minimum requirements.....". 

Sorry for the long message, I appreciate your time!   -Aubrey

[Damien Symonds]

Can you remind me, have you read this one?  https://www.damiensymonds.net/2014/03/how-aggressively-can-i-crop.html

[Aubrey]

I have before but I just re-read it for you. 6mega pixels or larger. 

[Damien Symonds]

Right.  And remember, the PPI value is completely meaningless.  Don't discard any images just because they say "72".

[Aubrey]

Ok that's good to know. I figured it an image only has 72 pixels per inch then wouldn't that print crappier than a pic that has 300 pixels per inch? I just need some bullet points and I promise I will save that info on my computer so I never have to bother you again about this. lol

[Damien Symonds]

https://www.damiensymonds.net/2011/11/why-ppi-doesnt-matter-yet-another.html

[Aubrey]

Then why in the hell is ppi even a thing?

[Damien Symonds]

Because of sharpening.  PPI is crucial for good sharpening.

https://www.damiensymonds.net/art_resample.html

[Aubrey]

Ok, yes I remember that now that you say it. Do I need to watch for anything else then? I've seen many charts online show how to convert pixels to inches for print..... But I trust you more than morons on google so please clear that one up for me.

[Damien Symonds]

Don't over-complicate the sizing thing.  If the image passes the 6-megapixel-test, and it passes your focus analysis, then that's all you need to worry about.  Then you can just choose your Crop Tool, set the exact size and print resolution you need in the Options Bar, then crop.

Then sharpen, then save.