Pixel Dimemsions vs PPI and Print Quality

chuckinsocal · March 6, 2008

Hi Gang,

I have a customer who sent me some jpgs for post processing in Photoshop. He sent me files that were 800 pixels wide at 180 PPI and that's what I sent him back.

Now he tells me that he wanted to get some poster sized prints made which means they need to be upsized to about 1600 pixels.

When I upsize them they look ok on my monitor. The question is can I upsize them that much and still get decent prints at say 30x40, and if so, should I upsize the pixel dimensions or the ppi or some combination thereof?

Here are the pics in question:

Thanks.

Chuck Cannova
http://chuckinsocal.SmugMug.com

claudermilk · March 6, 2008

He wants 30x40 with an 800 pixel file? Bleh. That's either 26 or 20 ppi. I'd ask if he has a larger file. Going by the help page that shows an image SM says they printed at 80ppi, you are still having to interpolate 4x the original file size. I think it's gonna be soft no matter what.

arodney · March 6, 2008

180ppi at the size you want the output is the minimum you should work with. Find out the size he wants, then figure you need 180ppi on up (to 480) and you've got enough pixels to work with.

chuckinsocal · March 6, 2008

Thanks Chris,

He states the what he sent me is the largest he has. He can't take more pictures because his car is layed up somewhere having some modifications done to it. So, I'm pretty much stuck with what I have.

Chuck Cannova
http://chuckinsocal.SmugMug.com

chuckinsocal · March 6, 2008

Thanks Andrew,

I had forgotten about that post about the print quality at lower a ppi.

Maybe what I'll do, since there are only a few colors in the image, is up the ppi a tad then up the pixel dimensions a tad, and run a sharpening filter on it.
That may produce a large print that is at least acceptable if not perfect. I think all he wants to do is stare at a picture of his car hanging on a wall anyway.

Does anyone have any comments on that plan?

Chuck Cannova
http://chuckinsocal.SmugMug.com

arodney · March 6, 2008

chuckinsocal wrote:

Does anyone have any comments on that plan?
http://chuckinsocal.SmugMug.com

Short of getting a bigger document, that's about it.

Good digital capture should go 2-3X in size which means at 180ppi, you might get 13 inches tops.

Art Scott · March 6, 2008

chuckinsocal wrote:

Hi Gang,

I have a customer who sent me some jpgs for post processing in Photoshop. He sent me files that were 800 pixels wide at 180 PPI and that's what I sent him back.

Now he tells me that he wanted to get some poster sized prints made which means they need to be upsized to about 1600 pixels.

When I upsize them they look ok on my monitor. The question is can I upsize them that much and still get decent prints at say 30x40, and if so, should I upsize the pixel dimensions or the ppi or some combination thereof?

Here are the pics in question:

Thanks.

Chuck Cannova
http://chuckinsocal.SmugMug.com

Chuck...
What are you uprezing with (software )....... it could be that using Genuine Fractals could save you some headache....they have a trial version at ONone software that is a full working trial....what I have done is to do my uprez and then preview it before saving....as long as you do not save it it doesnot count toward you trial cound (either 15 or 20 saved files or 30 days which ever comes first)......I have had fantastic luck with using GF my latest version is 4.0 or 4.5 (it was their first edition with the one clik uprez..amn is it sweet now because you can either uprez by percentages, or by dimension ( inches by inches) all in one step....be sure to read the instructions and when I had questions they were more than happy to help............

pathfinder · March 7, 2008

For a 40 in print, at 180 ppi, you will need 40 x 180 = 7200 pixels and you have 800. 7200/800 = 9x uprezzing.

Can this be uprezzed - sure. Will it provide acceptable image quality? To for me, no way. But if your client only wants something in his garage, perhaps.

This is not going to provide a gallery level print quality, no matter what you do, unless you can get access to the original file. Not even with Genuine Fractals. I would prefer to start with an image with 8000 pixels for a 40 inch print.

chuckinsocal · March 8, 2008

Thanks all for your replies and help.

After all is said and done, I did uprez the file by almost 2 1/2 times and ran sharpening filters to where it looked ok on the screen. And I told him I wasnt sure how it would print large but that he could try.

In the end, he hasn't ordered anything yet so it may all be for naught.

Oh well ... next!!

Thanks again,

Chuck Cannova
http://chuckinsocal.SmugMug.com

Pixel Dimemsions vs PPI and Print Quality

Comments