Q on DPI for printing

Archived from groups: rec.photo.digital (More info?)

As mentioned under other thread, when printed at Costco, pictures came out
beautiful.
My question is what DPI Costco or Walmart sets for printing digital images.
I assume that DPI # could affect the quality of prints. Am I missing here?
Carig

Archived from groups: rec.photo.digital (More info?)

Hi Craig,

Let me ask you again. I took pictures with Sony T1 camera (pictures were
taken at 3MP setting).
The JPG file size of each picture ranged from 1.3 - 1.5 MB.
I gave those to Costco for printing. I only know the graphic file size but
I have no idea what ppi.
How can I figure out those PPI?. BTW, what is ppi?
Please enlighten me. Thanks.

craig


"Craig Flory" <floryphotog@mindspring.com> wrote in message
news:53Epe.947$NX4.442@newsread1.news.pas.earthlink.net...
>I always give an image at 250 ppi. ( not dpi ... that is for printers that
> print regular printing things) For photos it is pixels per inch. I also
> recommend giving images as full 12 level .jpgs.
> Craig Flory
>
>

Archived from groups: rec.photo.digital (More info?)

David,

Thanks again. I fully agree with you. With my Canon inkjet printer, I
can change dpi as I wish. I normally use 250 dpi setting.
But I have no idea what is the DPI setting at Costco, Walmart or other
places. That was my question.

Then, Craig Flori is talking about ppi. I was very confused.

Craig


"David Dyer-Bennet" <dd-b@dd-b.net> wrote in message
news:m23brsu7ze.fsf@gw.dd-b.net...
> "Satoshi" <machocraig@hotmail.com> writes:
>
>> As mentioned under other thread, when printed at Costco, pictures came
>> out
>> beautiful.
>> My question is what DPI Costco or Walmart sets for printing digital
>> images.
>
> *Probably* 300 dpi. Someone who knew which mini-lab they were using
> and knew the specs could say for sure (and will probably be along
> shortly).
>
>> I assume that DPI # could affect the quality of prints. Am I missing
>> here?
>
> As a "could" -- absolutely, it can.
>
> There's a fairly broad consensus that 300dpi gets you 'full photo
> quality'.
>
> The surprising thing, to me, is how good some pictures printed at less
> than that, even *much* less than that, sometimes look. There are at
> least 4 framed 8x10 prints on the walls here printed at less than
> *half* that, and some of those were examined in piles of prints at
> higher resolution by picky photographers who do their own darkroom
> printing, and the comments were about the *photo*, not about any lack
> of resolution in the print.
>
> Doesn't mean you can *always* *rely* on lower resolution looking good.
>
> There's no reason I can see to consider printing below 300dpi *if you
> don't have to* -- but if you can't quite make the print size you want
> at 300dpi, it's worth a try; often the print will look great.
>
> Of course, all of this is irrelevant if the picture itself isn't any
> good to begin with. Resolution won't compensate for poor exposure,
> focus, motion blur, bad composition, bad color, poorly chosen moment,
> bad lighting, and so forth.
> --
> David Dyer-Bennet, <mailtod-b@dd-b.net>, <http://www.dd-b.net/dd-b/>
> RKBA: <http://noguns-nomoney.com/> <http://www.dd-b.net/carry/>
> Pics: <http://dd-b.lighthunters.net/>
> <http://www.dd-b.net/dd-b/SnapshotAlbum/>
> Dragaera/Steven Brust: <http://dragaera.info/>

Archived from groups: rec.photo.digital (More info?)

Thanks. craig


"Craig Flory" <floryphotog@mindspring.com> wrote in message
news:W%Gpe.1008$NX4.290@newsread1.news.pas.earthlink.net...
> As I said ... you do NOT use DPI when working with photos. That stands for
> Dots Per Inch. PPI stands for Pixels Per Inch. A digital photo has
> millions
> of pixels and not dots. Dots refer to half-tone screens which are used by
> printers who print forms and such as well as your ink-jet when printing
> out
> a letter or something similar. So when talking about taking an image to
> Costco or Walmart you should think about the ppi. When an image is saved
> on
> your computer you are saving it at a particular ppi setting. For example
> ...
> even if I did nothing to a digital image from my camera it is 250 pixels
> per
> inch right from the camera. Most pro labs and also Walmart want 250 ppi
> files. I hope this helps.
>
> Craig Flory
>
>

Archived from groups: rec.photo.digital (More info?)

Yes .. 72 ppi is a standard for monitors but not for printing. Images look
fine on a monitor but will not print well at all at 72 ppi. I am a
professional portrait photographer and most pro labs want a 250 ppi file as
do a lot of regular labs. I'd suggest asking what the labs prefer that you
might get prints made with.

Craig Flory

Archived from groups: rec.photo.digital (More info?)

"Satoshi" <machocraig@hotmail.com> writes:

> Thanks again. I fully agree with you. With my Canon inkjet printer, I
> can change dpi as I wish. I normally use 250 dpi setting.
> But I have no idea what is the DPI setting at Costco, Walmart or other
> places. That was my question.

At least with the Epson and HP printers I'm familiar with, driven by
Photoshop or Picture Window Pro, what happens is that the application
knows what physical dimension print I have asked for, and how many
pixels of image data are available, and it communicates that to the
printer driver. The printer driver then takes care of turning those
*pixels* into constellations of *dots* in the ink colors available to
it to make the image.

Dye sublimation and photo-paper digital printers are often less
flexible about this, though.

> Then, Craig Flori is talking about ppi. I was very confused.

Pixels per inch. When I want to be pedantic, I say "camera-original
pixels per inch". But since you seemed to be using "DPI" in the
common way for this sort of discussion, I went along with the
terminology rather than introducing a mostly-pedantic distinction.

The confusion is that some inkjet printers, in fact pretty much *all*
of them these days, quote very high "DPI" numbers. It stands for
"dots per inch" of course -- and the high numbers are true; those
printers can in fact put down many drops of ink on each linear inch of
paper printed. However, each of those dots is of JUST ONE of the
colors of ink the printer has. The Epson claim to "2880 DPI" printing
does NOT mean that they can put down a dot *of any color within the
printer gamut* that many times per inch; just a dot in ONE of the ink
colors in that printer.

So, to talk carefully about the original photo data available to the
printer, we talk about "(camera original) pixels per inch".
--
David Dyer-Bennet, <mailtod-b@dd-b.net>, <http://www.dd-b.net/dd-b/>
RKBA: <http://noguns-nomoney.com/> <http://www.dd-b.net/carry/>
Pics: <http://dd-b.lighthunters.net/> <http://www.dd-b.net/dd-b/SnapshotAlbum/>
Dragaera/Steven Brust: <http://dragaera.info/>

Archived from groups: rec.photo.digital (More info?)

"Satoshi" <machocraig@hotmail.com> writes:

> Default setting for ppi for my monitor (along with most of consumer
> monitors) is 72.
> 250 ppi must be a default setting of camera when raw data are compressed
> into jpg format.
> I just looked at the spec for Sony T1, I do not see anything about ppi
> setting.
> I wonder whether 250 ppi is a universal setting for digital cameras or not.
> Could you please comment on that? I am very important information from your
> postings.

Cameras don't agree on what PPI value to encode in the files. I've
seen 180, 200, 240, and 300, that I can remember.

The important thing is that *it doesn't matter*. The PPI value in a
digital file has no big significance. (It probably determines the
*default* size the image will import into page layout programs, but
you can also then adjust it in those programs. It really doesn't
matter much.)
--
David Dyer-Bennet, <mailtod-b@dd-b.net>, <http://www.dd-b.net/dd-b/>
RKBA: <http://noguns-nomoney.com/> <http://www.dd-b.net/carry/>
Pics: <http://dd-b.lighthunters.net/> <http://www.dd-b.net/dd-b/SnapshotAlbum/>
Dragaera/Steven Brust: <http://dragaera.info/>

Archived from groups: rec.photo.digital (More info?)

Satoshi wrote:
> Hi Craig,
>
> Let me ask you again. I took pictures with Sony T1 camera (pictures were
> taken at 3MP setting).
> The JPG file size of each picture ranged from 1.3 - 1.5 MB.
> I gave those to Costco for printing. I only know the graphic file size but
> I have no idea what ppi.
> How can I figure out those PPI?. BTW, what is ppi?
> Please enlighten me. Thanks.
>
> craig
>
>
> "Craig Flory" <floryphotog@mindspring.com> wrote in message
> news:53Epe.947$NX4.442@newsread1.news.pas.earthlink.net...
>
>>I always give an image at 250 ppi. ( not dpi ... that is for printers that
>>print regular printing things) For photos it is pixels per inch. I also
>>recommend giving images as full 12 level .jpgs.
>>Craig Flory

In the 3MP mode, the T1 captures 2048 x 1536 pixels.
If you had Costco print a 6 x 4 inch picture, the resolution that you
SENT to them would be 2048/6 = 341 pixels/inch.
I suspect that their Fuji Frontier machine prints ALL pictures at some
native resolution, probably 300 pixels/inch (ppi).
(The actual value they use will have to come from Fuji or someone in
this NG who specializes in this topic.)
If they receive an image at greater than 300 ppi, they resample it
downward to 300ppi.
If they receive an image at some lower resolution, say 240 ppi, they
resample the image upward to 300 ppi.
Bob Williams

Archived from groups: rec.photo.digital (More info?)

Hi Bob,

> I suspect that their Fuji Frontier machine prints ALL pictures at some
> native resolution, probably 300 pixels/inch (ppi).
> (The actual value they use will have to come from Fuji or someone in this
> NG who specializes in this topic.)
> If they receive an image at greater than 300 ppi, they resample it
> downward to 300ppi.
> If they receive an image at some lower resolution, say 240 ppi, they
> resample the image upward to 300 ppi.
> Bob Williams
>

When I read Bob's posting, I am getting the answer close. I need a little
more clarification on this.

> If they receive an image at some lower resolution,

When I open JPGs under Photoshop, images are open at 72 ppi resolution
which is the default setting of Photoshop.
For printing, I adjust dpi to 250 or 300 dpi, and then print size. In
another words, I can change resolution prior to printing.

But when I bring downloaded jpg images to Costco, what I know is their MB
size. I have no idea what ppi is.
The images were nor resampled, nor modified. So what I understand from
Bob's posting now is that Costco machine automatically sets resolution all
customers' digital images to 300 ppi for printing. Is that correct?
Regards, craig

Archived from groups: rec.photo.digital (More info?)

Thank you Jim,

That's the answer which I have been waiting for.
Thank you again.

Satoshi



"Jim Townsend" <not@real.address> wrote in message
news:11ah0h2ckjcutee@news.supernews.com...
> Satoshi wrote:
>
>
>> But when I bring downloaded jpg images to Costco, what I know is their MB
>> size. I have no idea what ppi is.
>> The images were nor resampled, nor modified. So what I understand from
>> Bob's posting now is that Costco machine automatically sets resolution
>> all
>> customers' digital images to 300 ppi for printing. Is that correct?
>
>
> Yes.. Costco will set the image to whatever it is they need.
>
> This is why they don't specify a PPI/DPI setting for images
> and this is why you can just ignore the PPI settings you see in
> Photoshop.
>
> The only important PPI setting is the one used to actually print
> the image. Since Costco is doing it, they're the ones that need
> to set the Image size and PPI :-)
>
>