Printing large format: up sample or send below resolution as is

[rogerthat]

Plan on printing some large format Chromaluxe white gloss aluminum prints

Using a vendor/trade printer I work with just outputs what I upload

My issue is I am using images from 20 mp camera, believe files are about 5500 pixels wide so decent resolution but vendor wants 300 dpi at actual size which would equate to only about half the size I wanted to print
Looking to print as large as 36" x 24" but at 300 dpi my source file is about 18" wide
Started as RAW files

Since most cameras I think produce images in this range, I imagine this is a common issue. What would you do

Not place this order
(This vendor only has large sizes for the 3:2 ratio I desire)

Have photoshop up sample to 300 dpi or 240 at least using their tools?
If so which one of the options in photoshop do you use?

Submit my lower resolution files as is and hope for a good result

Thanks

 

[rogerthat]

After a little more research it sounds like on-one has a software program many use to up sample to higher dpi , that sounds like the best option for me if they still are offering a free 30 day trail

 

[Tom Mann]

By far, the best thing to do is, if the printer offers this service, simply send them your current file and let them use THEIR RIP or other printer driver software to re-sample your file and transform it (in one step) to exactly the resolution their printing machine operates at.

The reason for doing it this way (if possible) instead of up-rez'ing it yourself to the approximate final size needed is that every time one changes the resolution of an image by re-sampling, whether up-rez'ing or down-rez'ing, one always loses a bit of detail / sharpness, so you want to do all the resampling and get to exactly the final required dpi in one step, not two.

That being said, there are printers who don't offer this service and require their customers to submit files at exactly the dpi needed by their press. If you have spoken to them and are absolutely sure they won't do this for you, only then you should consider software such as OnOne's "Perfect Resize" (formerly known as "Genuine Fractals").

FWIW, I have used Perfect Resize / Genuine Fractals for at least 5 years, and feel that it was the best product of this type on the market. However, IMHO, a year or two ago, I feel that it has been surpassed (in terms of quality of final product, but not convenience) by:
http://www.benvista.com/photozoompro

thereby relegating PerfectResize to the #2 spot.


HTH,

Tom M

 

[ZipedX]

Been waiting to see when you or Alb would answer this

 

[rogerthat]

Tom, thank you for the very detailed response.