DPI / Pixels conversion?

On 2010-12-04 04:58:56 -0800, Tuxedo said:

Bruce wrote:

[...]

Several people here have given you the answer.

Perhaps you chose not to make the effort to understand?


Sorry in that I don't understand the calculation method posted before.
Perhaps I'm just an idiot. Is there more than one answer? Ie. is there more
than one result depending on the screen size and resolution, in spite of
the fact that the image file does not change size between different systems.

My question is then: I have an 3300 x 2200 image and what DPI is
that image?

Tuxedo

First; What is the final physical size of the image in INCHES, or if
you prefer mm?

Now, if the final size is 11 x 7.33 inches and the res is 3300 x 2200
the DPI/PPI ( to please all on that part of the debate) is 300.

If the DPI/PPI is 100 the final physical size should be 33 x 22 inches.

If you wanted a 33 x 22 inch image at 300 DPI/PPI you would be looking
at 9900 x 6600.

If you do not have the ability to adjust the image, let the print shop
know what your intention is regarding final size. If they are not able
to figure things out, your question should be, "Where can I find a
decent print shop to print what I need"?
--
Regards,

Savageduck

"Tuxedo" wrote in message
...
bobwilliams wrote:

[...]

Send them the 3300 x 2200 pixel image.
That one has the most image information.
They will determine how large they want to make the picture to fit their
publication and can size the image accordingly.
It is a piece of cake for them to do that.
Bob Williams

That's just what I'm doing. What I'm still not able to figure out
following
all previous posts is now many DPI that is.

It is the number of DPI the people you send it to want it to be. They can
choose to print it at 200 DPI, 300 DPI or any other DPI they want. It is
almost meaningless to you. Send them the most pixels you can of the photo
as you want it. Their DPI will be based on the number of pixels you send
them and the physical size of the print they want.

Many people use 300 pixels per inch as a rule of thumb for good prints.
This isn't a hard and fast rule, it is that 300 pixels per inch is almost
always adequate. For some photos 200 pixels per inch may be adequate.

Ron

They have been as precise as they need to be, up to a point. But one
piece of information is missing (see last paragraph below).

I already said that, Bruce. You must not be listening!

David

"Bruce" wrote in message
...
"David J Taylor" wrote:
They have been as precise as they need to be, up to a point. But one
piece of information is missing (see last paragraph below).

I already said that, Bruce. You must not be listening!


I think several people have already said it. I was hoping that
repeating it might help it begin to sink in ...

... time will tell. ;-)

A newly appointed magazine editor has seen exactly the same problems with
his printers, but did only need it explaining once. As editor he actually
sets the image size on the page since he does the page layout. I think he
uses InDesign but I'm not sure.

David

On 12/4/10 PDT 6:25 AM, me wrote:
On Fri, 03 Dec 2010 09:19:27 -0800, John McWilliams
wrote:

On 12/3/10 PDT 3:35 AM, MG wrote:
wrote in message
...
Hi,

I've been asked to send high-res images in minimum 300 dpi to a print
publication. But I'm only familiar with the pixels concept. For example, I
have a set of images which are 1000x1500 pixels and another which are
3300x2200 pixels. Approximately, what dpi are these respective set of
images?

Thanks,
Tuxedo

1000/300 = 3.33 inches
1500/300 = 5 inches
So, at 300 dpi, the largest size you can have is 5 x 3.33 inches

3300/300 = 11 inches
2200/300 = 7.33 inches
So, at 300 dpi, the largest size you can have is 11 x 7.33 inches

For DPI in all instances on this page, substitute PPI. The original
request was stated in wrong terms, not uncommon even among the literate
in photography groups.

Then you've never dealt with DTP programs which make use of this
meta-data when importing graphics. It may an archaic and even
incorrectly phrased term, but that is what is used sometimes in the
publishing industry and the tools they may be using.

So, because a software company uses incorrect terminology that somehow
makes it all right to repeat the error—and then defend it to the hilt??

On 12/4/10 PDT 5:32 AM, Bruce wrote:
wrote:

Bruce wrote:

[...]

Several people here have given you the answer.

Perhaps you chose not to make the effort to understand?


Sorry in that I don't understand the calculation method posted before.


What you clearly don't understand is that no calculation is needed.


Perhaps I'm just an idiot. Is there more than one answer? Ie. is there more
than one result depending on the screen size and resolution, in spite of
the fact that the image file does not change size between different systems.

My question is then: I have an 3300 x 2200 image and what DPI is
that image?

0! zero, zilch, nada. It's PPI for digital images.
Do not confuse screen display with printing, or PPI with DPI.
The PPI of your image is divided by the number of inches per side, so
the answer can be anything.

USUAL ranges for HQ printing is between 240 and 360 PPI.

The DPI can be anything you want it to be. That is the point that you
have so comprehensively missed. DPI is completely arbitrary.

No; he has no control over the DPI. None; those who print do/will. He
can submit a lot of pixels, and the PPI depends entirely on the size at
which the image will be printed.

Shame an old hand being so careless with precise terms. PPI is not DPI,
never has been.

--
John McWilliams

On 12/4/10 PDT 5:53 AM, Floyd L. Davidson wrote:
wrote:
bobwilliams wrote:

[...]

Send them the 3300 x 2200 pixel image.
That one has the most image information.
They will determine how large they want to make the picture to fit their
publication and can size the image accordingly.
It is a piece of cake for them to do that.
Bob Williams

That's just what I'm doing. What I'm still not able to figure out following
all previous posts is now many DPI that is.

Perhaps the question does not make sense?

Obviously it does not make sense. DPI is Dots Per Inch.
Pixels are the dots... but until you say how large the
print will be there *can't* be a unique number for DPI.

If the 3300x2200 pixel image is printed at 300 DPI you
get an image the is 11"x7-1/3". If that exact same
image is printed at 22"x14-2/3" it is at 150 DPI.

If the specify DPI, then they *necessarily* have to also
specify either the size in pixels for the image or the size
in inches of the print.

You're confusing the two terms. Most modern 300 PPI images are printed
at 1400 DPI.
Can you grok that?

--
lsmft

On 12/4/2010 7:05 PM, Bruce wrote:
wrote:
The publisher has used the expression 300 dpi, but that's a common
misconception. They mean 300 pixels per inch.


The publisher I work for (for part of the year) always calls it DPI.

The origin of this is in the screens that were used to shoot half
tones (photographs) to enable them to be offset printed. They were
always referred to by their DPI.


Brucie seems to have more jobs than Carter had liver pills.

--
Peter

On 12/4/10 PDT 4:05 PM, Bruce wrote:
wrote:
The publisher has used the expression 300 dpi, but that's a common
misconception. They mean 300 pixels per inch.


The publisher I work for (for part of the year) always calls it DPI.

Your publisher is old school. They are not synonymous.

The origin of this is in the screens that were used to shoot half
tones (photographs) to enable them to be offset printed. They were
always referred to by their DPI.

That was then; this is now. Please try to keep up.

--
lsmft

On 12/4/2010 9:22 PM, John McWilliams wrote:
On 12/4/10 PDT 5:53 AM, Floyd L. Davidson wrote:
wrote:
bobwilliams wrote:

[...]

Send them the 3300 x 2200 pixel image.
That one has the most image information.
They will determine how large they want to make the picture to fit
their
publication and can size the image accordingly.
It is a piece of cake for them to do that.
Bob Williams

That's just what I'm doing. What I'm still not able to figure out
following
all previous posts is now many DPI that is.

Perhaps the question does not make sense?

Obviously it does not make sense. DPI is Dots Per Inch.
Pixels are the dots... but until you say how large the
print will be there *can't* be a unique number for DPI.

If the 3300x2200 pixel image is printed at 300 DPI you
get an image the is 11"x7-1/3". If that exact same
image is printed at 22"x14-2/3" it is at 150 DPI.

If the specify DPI, then they *necessarily* have to also
specify either the size in pixels for the image or the size
in inches of the print.

You're confusing the two terms. Most modern 300 PPI images are printed
at 1400 DPI.
Can you grok that?


The Epson 2880 & 3880 go to 2880 dpi. Neither uses more ink, but just
prints a l o t m o r e s l o w l e y.

--
Peter