Hi, Kevin...and thanks for the reply and help...
I'm not quite sure how this works out:
>A 800x600 image at 72 dpi is exactly the same
>as a 800x600 image at 300 dpi.
>They both weigh in at 1.4MB
I took a 1051 x 2098 image and at 300 dpi it's 3,067KB.
At 72 dpi, it's 360 x 503 and 220KB...
That's quite a difference when the file is uploaded and displayed
on screen. They both can be made to fit a 320 wide area onscreen,
but the 72 dpi resolution image is obviously more desirable because
of reduced file size that's loading onto the page.
Now, on the print side, of course, the 300 dpi is more desirable, but
that file is for downloading only, not display...that's where the 72 dpi
file would come into play...
Concerning cfx_image...I had a hard time understanding the "introduction"
that came with the tag. It does appear to have one feature that I must
have:
being able to specify width only and have heighth automatically calculated
by the tag.
I'm also looking at CF_MagickTag and ImageMagick, but I'm not sure
the heighth parameter is optional. I've got an email into them waiting for
an answer on that one.
I did notice that ImageMagick can calculate resolution and return that
as a variable and can also determine the size of an image and return that
as a variable. If I can get the dimensions as variables then I can
calculate
desired heighth based on desired width and that would solve the problem.
So there just may be a soluion...
But what do you think about my understanding above referencing your
response?
Rick
> -----Original Message-----
> From: Kevin Graeme [mailto:[EMAIL PROTECTED]
> Sent: Thursday, September 11, 2003 9:48 AM
> To: CF-Talk
> Subject: Re: Image manipulation
>
>
> Rick,
>
> You're half right and half wrong, or you're not explaining
> the other half
> clearly. You are correct that a 5x7 at 300dpi is bigger than
> a 5x7 at 72dpi.
> However, a 320 pixel wide image is going to be the exact
> same file size
> regardless of dpi.
>
> DPI is a virtual measurement derived by the total number of
> pixels divided
> by the display size of the image in inches. DPI doesn't
> really exist, only
> pixels exist and the display of those pixels. A 800x600
> image at 72 dpi is
> exactly the same as a 800x600 image at 300 dpi. They both
> weigh in at 1.4MB,
> but the 72dpi will print at 11.1"x8.3" and the 300dpi will
> print at 2.6"x2".
> The 72 dpi prints bigger just because you're stretching the
> same number of
> pixels over a larger area. And obviously, the apparent
> quality also goes
> down. But it's the same image either way.
>
> So before you try to set the display size thus dpi of the
> image, you need to
> calculate the absolute pixel sizes you're looking for. For instance:
>
> 8x10 at 300dpi = 33.3x41.6 at 72dpi = 2400 x 3000 pixels
> 5x7 at 300dpi = 20.8x29.1 at 72dpi = 1500 x 2100 pixels
>
> So those pixel measurements are what you are really shooting
> for. Size your
> images to those pixel values and if your tag of choice
> doesn't let you set
> the dpi, it doesn't matter that much because the end-user's
> software will
> raise the effective dpi when they make the display size of the image
> smaller. Many online image companies do it this way.
>
> BTW, I'd recommend thouroughly testing the image tag on a
> development server
> before putting it on your production box. The cfx_image tag
> crashed our
> server when I tried it a few years ago, but others swear by it.
>
> -Kevin
>
> ----- Original Message -----
> From: "Rick Faircloth" <[EMAIL PROTECTED]>
> To: "CF-Talk" <[EMAIL PROTECTED]>
> Sent: Wednesday, September 10, 2003 11:28 PM
> Subject: RE: Image manipulation
>
>
> > I've seen that cfx_image can resize the dimensions of a photograph,
> > I just haven't found anything that tells me whether the
> tag can read
> > resolution (dpi)
> > and allow that to be adjusted...
> >
> > A photo that's 320 pixels wide is a much larger file at
> 300 dpi than one
> > that is 72 dpi...
> >
> > For example, a 5x7 inch photo at 300 dpi is a 9MB
> file...at 72 dpi it's
> > 531KB.
> > And since a typical computer screen can only display 72
> dpi, there's no
> need
> > in
> > trying to display a 300 dpi photo when a 72 dpi will be
> more appropriate.
> >
> > Rick
> >
> >
> > > -----Original Message-----
> > > From: Doug White [mailto:[EMAIL PROTECTED]
> > > Sent: Wednesday, September 10, 2003 11:43 PM
> > > To: CF-Talk
> > > Subject: Re: Image manipulation
> > >
> > >
> > > I suggest cfx_image for resizing on the fly
> > >
> > >
> > >
> > > ======================================
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> > > ----- Original Message -----
> > > From: "Claude Schneegans" <[EMAIL PROTECTED]>
> > > To: "CF-Talk" <[EMAIL PROTECTED]>
> > > Sent: Wednesday, September 10, 2003 10:17 PM
> > > Subject: Re: Image manipulation
> > >
> > >
> > > | >>if I want a 300 dpi image (the original) available for
> download,
> > > | >>but want to display a 72 dpi version
> > > |
> > > | What does mean "dpi" when the image has been scanned on an
> > > equipment you don't
> > > know at a resolution you don't know
> > > | and it will be displayed on a screen you don't know?
> > > |
> > > | Talk pixels, not dpi. All you need to know is that about
> > > 50% of users now have
> > > 1024 pix or more, and most of the rest
> > > | has at least 800. Within 2 or 3 years it will be 50% 1024
> > > and 50% 1600 or
> > > more.
> > > |
> > > |
> > >
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