Printing resolution

[George Marinos]

Hi
I have to print a number of files from a mobile phone.The dimensions of the files are:
27.64x20.73 at 300.I want to print photos 41.45x30.09 which results in a resolution of 200.
What do you think is better:keeping the resolution at 200 ,downscaling at 180 or upscaling
at 300 or even at 360 since my printer is an Epson 9900
Thank you

[PeterAit]

Wow, a 51 megapixel phone camera! What brand? I gotta get one!

Seriously, your figures must be wrong. 27.64 x 20.73 at 300 works out to a 8291 x 6218 pixel image.

[John R Smith]

Peter

George is in Greece. Perhaps we are talking about centimeteres, not inches?

John

[Bart_van_der_Wolf]

Wow, a 51 megapixel phone camera! What brand? I gotta get one!

Seriously, your figures must be wrong. 27.64 x 20.73 at 300 works out to a 8291 x 6218 pixel image.

More likely, since the OP seems to be from Greece and presumably used centimeters for the dimensions, 3265 x 2448 = 8MP.

Thus, he probably will get the best compromise for the intended output size by upsampling to 360 ppi, apply some Smart Sharpening, and hope for the best.

Personally, I'd do the printing with Qimage for superior resampling results (compared to Photoshop) at 720 ppi, but I have to assume the OP doesn't use it. Recommended though, especially if it is a recurring type of print job.

Cheers,
Bart

[George Marinos]

Yes it is in centimeters.The quality of the files is remarkable good if you consider that they come from a mobile phone.
My client will make an exhibition with this photos .I started to print with 300 but continue with 360 as you suggest.
Thank you all for the reply
George

[PeterAit]

But if he is using cm, which does seem likely, wouldn't the resolution of 300 be dots per centimeter, not per inch? Small point, but it's hard to answer his question without being sure.

[George Marinos]

I am sorry about the confusion.The dimensions are:  27.64 cmx20.73 cm at 300 pixels/inch
George

[PeterAit]

Thanks for the clarification (although I really wanted that 521 MP camera  .)

In my experience, 200 dpi will be fine for printing. 180 is the minimum acceptable, but is not a "magic number" that you should try to achieve by down-sampling.

[Garnick]

Hi George,

I agree with Peter. It's generally better to stay with the native file resolution, unless it falls below the 180ppi mark. I print quite a variety of images, some my own but mostly for my customers. The only time I would upres a file is if it's below 150ppi, in which case I would probably go to 240. With today's cameras even a 150ppi file will print very well on the newer printers(x900 series). Of course it also depends on the image content as well, but again, I would stay with the 200ppi and print as is.

Gary

[Farmer]

On a side note, I don't know of anyone in a metric country who uses ppcm or dpcm.  It's one of those anachronisms that it's easier to just keep :-)

[Bruce Watson]

On a side note, I don't know of anyone in a metric country who uses ppcm or dpcm.  It's one of those anachronisms that it's easier to just keep :-)

With a world population close to 7 billion, around 6.6 billion are fully metric. That's greater than 94% of the world population. Most of those people really don't think in terms of inches.

Lightjets, for example: the "normal" resolution of a LightJet is 120 ppcm, which works out to 304.8 ppi.

And pixels haven't been around long enough -- only since 1965 when the word was coined by Fred C. Billingsley of JPL -- to qualify as an anachronism. In 1965, more than 90% of the world's population was metric. Like everything that has to do with inkjet printing, none of it has been around long enough for anyone to credibly claim that "we've always done it that way".

[Farmer]

Most of those people are not involved in photography or digital printing.