72 vs 300 dpi

Hi, I am traditionally a 35mm photography just now accepting that I have to commit to my 8 megapixel Canon 20D.
If I take a RAW image, what is the best way process the image and be able to print a excellent quality 11x17?
If a RAW image at 8 megapixels printed at 300dpi ( from originally one that is 72 dpi ) is best at 8 x 12 any larger print would make it lose some quality if I kept it at 300 dpi.
I can use Photoshop or Apeture, print a JPEG or a TIFF.
Any suggestions on the best way to get the most out of my camera??
Any other 20D'ers out there? Thanks!

On Tue, 19 Sep 2006 00:19:16 +0100, Gretchen's Photography
wrote:


Hi, I am traditionally a 35mm photography just now accepting that I have
to commit to my 8 megapixel Canon 20D.
If I take a RAW image, what is the best way process the image and be
able to print a excellent quality 11x17?
If a RAW image at 8 megapixels printed at 300dpi ( from originally one
that is 72 dpi ) is best at 8 x 12 any larger print would make it lose
some quality if I kept it at 300 dpi.
I can use Photoshop or Apeture, print a JPEG or a TIFF.
Any suggestions on the best way to get the most out of my camera??
Any other 20D'ers out there? Thanks!


I would suggest using Photoshop's image-sizing dialog,
and possibly not upsampling at all.

In other words, set the tool to *not* resample, and then
simply enter the desired output (print) dimensions -- and
see where the final resolution falls. As long as it's not
much below (say) 240 dpi, you're good-to-go.


rafe b
www.terrapinphoto.com

Raphael Bustin wrote:
On Tue, 19 Sep 2006 00:19:16 +0100, Gretchen's Photography
wrote:

Hi, I am traditionally a 35mm photography just now accepting that I have
to commit to my 8 megapixel Canon 20D.
If I take a RAW image, what is the best way process the image and be
able to print a excellent quality 11x17?
If a RAW image at 8 megapixels printed at 300dpi ( from originally one
that is 72 dpi ) is best at 8 x 12 any larger print would make it lose
some quality if I kept it at 300 dpi.
I can use Photoshop or Apeture, print a JPEG or a TIFF.
Any suggestions on the best way to get the most out of my camera??
Any other 20D'ers out there? Thanks!


I would suggest using Photoshop's image-sizing dialog,
and possibly not upsampling at all.

In other words, set the tool to *not* resample, and then
simply enter the desired output (print) dimensions -- and
see where the final resolution falls. As long as it's not
much below (say) 240 dpi, you're good-to-go.


In the RAW conversion dialogue in PS you can upsize there, into 8 or 16
bit images. That's where I'd upsample if at all.

Just a small point, but one that'll perhaps help keep things clearer for
you in the future, all the above should be ppi. DPI comes into play
either when you print, or when you scan. Sometimes they're
interchangeable, sometimes decidedly not.

Good luck!

--
John McWilliams

Gretchen's Photography wrote:
Hi, I am traditionally a 35mm photography just now accepting that I have
to commit to my 8 megapixel Canon 20D.
If I take a RAW image, what is the best way process the image and be
able to print a excellent quality 11x17?
If a RAW image at 8 megapixels printed at 300dpi ( from originally one
that is 72 dpi ) is best at 8 x 12 any larger print would make it lose
some quality if I kept it at 300 dpi.
I can use Photoshop or Apeture, print a JPEG or a TIFF.
Any suggestions on the best way to get the most out of my camera??
Any other 20D'ers out there? Thanks!


The image is just 3504 x 2336 pixels
72 ppi (not dpi) is just a default setting that Photoshop uses for
bookkeeping purposes.
Since your original 20D's image is 3504 X 2336 pixels, even if you do
the barest minimum of cropping to get to an 11 x 17 aspect ratio, your
image will have only 206 ppi (3504/17) resolution.
It will be less than that if you crop more severely.

Any good printer will print at about 240-300 ppi (ignore the 1440 dpi
claims....that is an entirely different beast).
Now at this point you can send the 206 ppi (or smaller) image to the
printer and IT will UPsample the image to whatever the native
resolution of the printer is.....OR.....you can Resample (bicubic) the
image yourself in Photoshop to 300 ppi and then send it to the printer.
Probably there would not be much, if any, difference either way.
Also I doubt that there would be much, if any, difference whether you
send it in tiff or highest quality jpeg. To be absolutely safe, you
could choose tiff. (But I never do.)
Bob Williams

Gretchen's Photography wrote:
Hi, I am traditionally a 35mm photography just now accepting that I have
to commit to my 8 megapixel Canon 20D.
If I take a RAW image, what is the best way process the image and be
able to print a excellent quality 11x17?
If a RAW image at 8 megapixels printed at 300dpi ( from originally one
that is 72 dpi ) is best at 8 x 12 any larger print would make it lose
some quality if I kept it at 300 dpi.
I can use Photoshop or Apeture, print a JPEG or a TIFF.
Any suggestions on the best way to get the most out of my camera??
Any other 20D'ers out there? Thanks!


While some people hold out for 300 ppi, many of us find acceptable
results as low as 200 ppi. Of course it depends somewhat on the
subject, but many of us just recommend 200 - 300 ppi. Yeah, 300 may be
a bit sharper, but most printers do an acceptable job with 200.

wrote:

Hi, I am traditionally a 35mm photography just now accepting that I
have to commit to my 8 megapixel Canon 20D.
If I take a RAW image, what is the best way process the image and
be able to print a excellent quality 11x17?

That depends on the printer. The procedure for really excellent
quality is different for different printers. In particular halftone
devices such as ink-jets require a different procedure from contone
devices such as silver-halvide photoprinters. But in general, you
need to resize the pixel count to match the optimum ppi figure (not
dpi figure) for the printer.

Example: Let's say you print a 20D file at an top quality Epson inkjet
halftone device. These perform best if your source is resized to 720
ppi (NB: again ppi, /not/ dpi). If the source is not 720 ppi, the
printer will do the interpolation for you, usually with a worse result
than if you do it yourself. So to print at 17x11 on an Epson inkjet,
you should convert fra RAW to 16-bit TIFF, make tone and curves
adjustment, trim your original file to a 1.55 aspect ratio, use
special printing preparation software such as Qimage to up the
resolution to 12240x3300 pixels, and finally sharpen with a value
suited for the print resolution.

If a RAW image at 8 megapixels printed at 300 dpi (from originally
one that is 72 dpi) is best at 8 x 12 any larger print would make it
lose some quality if I kept it at 300 dpi.

I am not sure what you mean here. The embedded ppi figure in the file
(72, 300, whatever) is in this context meaningless. The "real"
ppi-figure is what you get when you divide the number of pixels along
one of the sides with the number of inches that side is in the print
(ppi = pixels per inch).

The "native" image file from the EOS 20D is 3504 pixels on its long
side, so printed at 12 inches, that is 3504/12 = 292 ppi, and printed
at 17 inches, that becomes 3504/17 = 206 ppi.

I can use Photoshop or Apeture, print a JPEG or a TIFF.
Any suggestions on the best way to get the most out of my camera??

The key to excellent print quality is to make sure pixel count of the
file matches the optimum ppi figure for the printer, and to use
suitable software to prepare the file by changing the pixels
dimensions. Specialized software for this task is usually better than
the Photoshop's bicubic method.

For some background, take a look at this page:
http://hannemyr.com/photo/pixels.html
--
- gisle hannemyr [ gisle{at}hannemyr.no - http://hannemyr.com/photo/ ]
------------------------------------------------------------------------
Sigma SD10, Kodak DCS460, Canon Powershot G5, Olympus 2020Z
------------------------------------------------------------------------

Gisle Hannemyr wrote:

The key to excellent print quality is to make sure pixel count of the
file matches the optimum ppi figure for the printer, and to use
suitable software to prepare the file by changing the pixels
dimensions. Specialized software for this task is usually better than
the Photoshop's bicubic method.

G- Have you done comparison tests as to how upsizing at the RAW
conversion does vs. upsizing with, say, Qimage?

To the OP: what GH says will get you the absolute best, but in many
cases most of us wouldn't know the difference unless we were examining
two prints side by side and very closely.

--
John McWilliams

Gisle Hannemyr wrote:
John McWilliams writes:
Gisle Hannemyr wrote:

The key to excellent print quality is to make sure pixel count of
the file matches the optimum ppi figure for the printer, and to use
suitable software to prepare the file by changing the pixels
dimensions. Specialized software for this task is usually better
than the Photoshop's bicubic method.

G- Have you done comparison tests as to how upsizing at the RAW
conversion does vs. upsizing with, say, Qimage?

Not until now.

I did, however, a quick test (visual ispection of 100% crops side by
side on the screen) just now.

It looks as if 2x in SPP is visibly sharper and less pixelated than
Qimage, while 1.81x in ACR (PS CS) is about par with Qimage. (Both
compared to same ratio interpolation).

But the RAW converters I have available (SPP and ACR) only to let me
interpolate to a limited number of preset ratios (2x for SPP and 1.81x
and 1.35x for ACR), so I can't see how I can use this to optimize the
PPI for an arbritary size?

Nor do I know, but I've always been a bit suspect of the benefits of
upsizing to the exact ratio of the printer's alleged optimum ppi.

To the OP: what GH says will get you the absolute best, but in many
cases most of us wouldn't know the difference unless we were
examining two prints side by side and very closely.

That is true. The differences are in most cases not noticable.
But sometimes - for instance when trying to render thin hairlines
like a telegraph wire, without it breaking up in places, it does
matter.

Amen. I just didn't want any chance of someone being discouraged
thinking he'd have to follow a precise and laborious path to get very
good prints.

--
john mcwilliams

A simple answer is to keep the PPI not less than 150 nor more than 300.
Most people at reasonable viewing distances will not be able to tell the
difference in most cases. It is more important to use the ink that the
printer mfg recommends for the printer to get the best results and
reduce fading.

John McWilliams wrote:

Gisle Hannemyr wrote:

John McWilliams writes:

Gisle Hannemyr wrote:


The key to excellent print quality is to make sure pixel count of
the file matches the optimum ppi figure for the printer, and to use
suitable software to prepare the file by changing the pixels
dimensions. Specialized software for this task is usually better
than the Photoshop's bicubic method.


G- Have you done comparison tests as to how upsizing at the RAW
conversion does vs. upsizing with, say, Qimage?


Not until now.

I did, however, a quick test (visual ispection of 100% crops side by
side on the screen) just now.

It looks as if 2x in SPP is visibly sharper and less pixelated than
Qimage, while 1.81x in ACR (PS CS) is about par with Qimage. (Both
compared to same ratio interpolation).

But the RAW converters I have available (SPP and ACR) only to let me
interpolate to a limited number of preset ratios (2x for SPP and 1.81x
and 1.35x for ACR), so I can't see how I can use this to optimize the
PPI for an arbritary size?


Nor do I know, but I've always been a bit suspect of the benefits of
upsizing to the exact ratio of the printer's alleged optimum ppi.


To the OP: what GH says will get you the absolute best, but in many
cases most of us wouldn't know the difference unless we were
examining two prints side by side and very closely.


That is true. The differences are in most cases not noticable.
But sometimes - for instance when trying to render thin hairlines
like a telegraph wire, without it breaking up in places, it does
matter.


Amen. I just didn't want any chance of someone being discouraged
thinking he'd have to follow a precise and laborious path to get very
good prints.

measekite wrote:
A simple answer is to keep the PPI not less than 150 nor more than 300.
Most people at reasonable viewing distances will not be able to tell the
difference in most cases. It is more important to use the ink that the
printer mfg recommends for the printer to get the best results and
reduce fading.

Yes, that is a simple answer.

Kindly bottom post and trim your replies. This is not the
comp.periphs.printers NG!

--
John McWilliams