Printing - to re sample or not to - DPI's

[FreeloaderJoe]

I'm getting some enlargements done at DS Colourlabs in Didsbury.
Phoned them today and they said it was best that i resized my prints myself to the exact size i want, import their colour profiles and send in my order.

What has confused me though is the DPI.
They print at 300 DPI - and my photos seem to be at 240 DPI as standard

Firstly if possible should i readjust the DPI to 300? This is possible with my resolution printing upto 15x10 inch.

What happens if i don't have 300 dpis to spare for the print size? Should i get photoshop to resample or should i not?

Any help appreciated

 

[StewartR]

The DPI setting embedded in the EXIF data of your photo is irrelevant. Changing it won't have any effect.

The only thing that matters is the number of pixels. If they print at 300 DPI then you need to ensure your image has 300 pixels for every inch of print size. So if you want a 15x10 print then your image needs to be 4500 x 3000 pixels. If it's smaller than that, you'll need to resize it.

EDIT: Strictly speaking it's PPI - pixels per inch - rather than DPI. Many people seem to use the terms interchangeably. But when you see a printer advertised as 1440 DPI, you need to be aware that it's using several Dots of ink to make up one Pixel, so the PPI count will be much smaller. When DSCL say 300 DPI they really mean 300 PPI.

 

[Craikeybaby]

I always resample images before sending to a printer, I set the PPI to the requested setting, then make sure the image size (in inches) is the size I want it to print out, in both dimensions, to ensure the aspect ratio is correct.

If you need to make extra pixels my software recomendations would be (in order of preference): Genuine Fractals, Lightroom, Photoshop with Bicubic smoother selected.

 

[Blue Eagle]

Sorry to hijack, but i think it is basically the same question.......is it a bad thing to print using a PPI lower than 300 (as 300 seems to be the standard), leaving the photo at its original resolution, rather than upscaling?

I've just sent off for a 30"x20" and left the resolution at 4186x2791 (11.6Mp), but if it was to be 300PPI, then it should have been 9000x6000 (54Mp) ....suppose i find out tomorrow when it is on the wall if this will be an issue haha!

 

[StewartR]

is it a bad thing to print using a PPI lower than 300 (as 300 seems to be the standard), leaving the photo at its original resolution, rather than upscaling?

I've just sent off for a 30"x20" and left the resolution at 4186x2791 (11.6Mp), but if it was to be 300PPI, then it should have been 9000x6000 (54Mp) ....

The photo will NOT be printed at a lower resolution. The printer can't physically do that. It will be designed to print at a specific resolution, which wil be 300 PPI or 288 PPI or 256 PPI or some other similar number.

If it's a 300 PPI printer and you want the print to be 30x20" then the printer will have to print 54 million pixels. You've only supplied 11.6 million, so the printer will have to make up the remaining 42.4 million. It's a sobering thought, isn't it, that 80% of what's being printed is purely imaginary! The real question is whether it's better to make up those 42 million pixels yourself (ie upsample in Photoshop or another application before sending the file off to print) or whether it's OK to let the printer do it itself.

I guess you'll have the answer soon.

 

[The23rdman]

I always resample images before sending to a printer, I set the PPI to the requested setting, then make sure the image size (in inches) is the size I want it to print out, in both dimensions, to ensure the aspect ratio is correct.

If you need to make extra pixels my software recomendations would be (in order of preference): Genuine Fractals, Lightroom, Photoshop with Bicubic smoother selected.

I'm trialing Alien Skin Blow Up at the mo and it's proving superb.

 

[fezzr]

The real question is whether it's better to make up those 42 million pixels yourself (ie upsample in Photoshop or another application before sending the file off to print) or whether it's OK to let the printer do it itself.

exactly, so without knowing what equipment the company use then its hard to tell. So it is usually safer to do it yourselfs.