Who should upsize for printing?

I outsource my printing. The RAW files out of my 40D are 240ppi and (roughly) 11+x17+ inches.

If I want to print a 12x18 should I upsize the file myself and increase it to 300ppi? Or, should I leave it as is and let the lab do the upsizing?

This question is even more critical for printing poster size (24x36).

You should check with your print "providers". Some want you to resize to a specific resolution, some want you to just set your ppi "tag" to a fixed resolution, and some will just accept your file and print it to your desired print size.

When printing yourself, you often can get great results without resizing, just sending the pic to your printer, although a lot of folks prefer to resize and apply "output sharpening" before printing.

I'd run some tests to see what works!

Yep depends on your lab. For example the lab I regularly use specifies 8-bit, Adobe 1998 @ 300ppi - as I usually print large (30"+) I often need to "up-rez."

I prefer to adjust things myself, then I can be sure that its done right. Too many of these businesses employ people who have no interest in what they are doing!

It's safer to do it yourself.

jefzor wrote in post #16313462
It's safer to do it yourself.

And *much* more satisfying.

https://photography-on-the.net …/showthread.php​?p=3740438

photoguy6405 wrote in post #16313134
I The RAW files out of my 40D are 240ppi and (roughly) 11+x17+ inches.

The RAW files out of your camera are not anything ppi. ppi is an output resolution that you put in the computer to send to the output device. I think you are confusing your default computer setting of 240ppi with what you think is determined by the camera.

To answer the other part, I would definitely do upsampling yourself and not leave it to somebody else.

http://www.youtube.com …4mV3NsLmXw&feat​ure=relmfu