One of the new features of the upcoming release of Polacolor Insight is
the
ability to use one of several decimation techniques from nearest
neighbor(lowest quality) to bicubic(highest quality also longer). Your
choice would depend on use.
David
Actually, the best technique use sinc
use downsample and upsample, and I think they both are
easier to understand.
Art
Steve Greenbank wrote:
- Original Message -
From: Austin Franklin [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Tuesday, October 23, 2001 11:56 PM
Subject: RE: filmscanners: RE: filmscanners: Re: Hello
Pretty violent term for describing removal of some pixels, if you ask
me... I too use downsample and upsample, and I think they both are
easier to understand.
Art
Yes, it's roots seem to be quite violent. For people who design and work
with digital imaging systems, it's a very common, and
Rob Geraghty wrote:
AFAIK digital cameras produce files which are set to 72 dpi. Can anyone
who has one check this? I know it's been driving my brother nuts when people
send digicam pics at screen resolutions and expect him to print them in
a magazine!
Our Sony Digicam gives images at 72
OK, now I have a better understanding of your question.
The big problem most people have is seeing images are composed of two
things, dimension (the size in inches, for instance) and then resolution
(the number of pixels that make up each inch.)
This makes things more complex than necessary.
Harvey,
If I'm reading your comments (below) correctly, the only difference
between your old scanner and your new one in this matter is how the
software operates. A 72 dpi scan at 200% making a 8 x 12 screen image
is the exact same thing as a 144 dpi scan of a 4 x 6 print. And you
don't need
As mentioned, the 72 dpi number is a bit long in the tooth these days.
It was a Mac standard used for screen fonts, but is no longer valid for
most monitors which use higher resolutions. Larger monitors (17, 19, or
21) often function at 80-100 dpi or even slightly higher.
Now, 72 dpi (or even
Right, but scan at 72 dpi and you get crap. One day I'll understand
all this. ;-)
At 1:08 PM -0700 10/22/01, Ken Durling wrote:
I guess I'm missing the point here. If I were to scan even a 4x6
print at 72 dpi, and then want to display it anything larger than
288x432 pixels, wouldn't
Arthur,
You bring up interesting points. I have never actually done side by side comparisons
of the PS or scanner
downsampling to see if there is a noticeable difference. However, I have not
comprehended a difference by 'my
memory' (always a scary proposition) going either way. I will try to
Photography [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, October 23, 2001 5:10 PM
To: [EMAIL PROTECTED]
Subject:Re: filmscanners: RE: filmscanners: Re: Hello, thanks, and
more.
Arthur,
You bring up interesting points. I have never actually done side by side
comparisons of the PS or scanner
One of the new features of the upcoming release of Polacolor
Insight is the
ability to use one of several
decimation
^
techniques from nearest
neighbor(lowest quality) to bicubic(highest quality also longer). Your
choice would depend on use.
David
David,
Im very
PROTECTED]
Subject:RE: filmscanners: RE: filmscanners: Re: Hello, thanks, and
more.
One of the new features of the upcoming release of Polacolor
Insight is the
ability to use one of several
decimation
^
techniques from nearest
neighbor(lowest quality) to bicubic(highest
Thumbs Plus (a shareware browser and processor) has these options for resizing (OK
Austin, 'decimate'!), in order of low to high quality:
- nearest neighbour
- bi-linear
- resample
- bicubic
My experiments revealed that the first 2 weren't very good (I think they were only
there for those
Thumbs Plus (a shareware browser and processor) has these
options for resizing (OK Austin, 'decimate'!),
Thanks! ;-) Basically, decimate means to take away, interpolate means to
add...so when you resize, it depends on whether you go up or down.
Actually, the algorithms should be different
Strictly speaking decimation means remove 1 in 10 hence the dec so it's
definitely NOT the correct term even if some illiterate yank coined the
phrase.
;-)
Strictly speaking, in a normal English conversation (not engineering) you
are entirely correct, sir.
Personally I use down-sample (and
PM
To: [EMAIL PROTECTED]
Subject:Re: filmscanners: RE: filmscanners: Re: Hello, thanks, and
more.
- Original Message -
From: Austin Franklin [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Tuesday, October 23, 2001 11:56 PM
Subject: RE: filmscanners: RE: filmscanners: Re: Hello
Whether in the real world it is preferable to adjust image colors
using 16 bits per channel rather than 8 bits per channel has been
a long standing argument.
It is a fact that it is preferable to make tonal moves using 16 bits per
channel. Whether you can detect the difference is yet another
In a message dated 10/21/2001 9:54:44 PM Pacific Daylight Time, [EMAIL PROTECTED] writes:
How do you resize an image without losing/adding pixels? Just by
specifying the inch dimension? That's something I've never been clear
about - whether choosing inch, cm, pixels or whatever in the size
On Sun, 21 Oct 2001 20:53:10 -0700, you wrote:
with HP Photosmart
with my 5200C.
I meant HP PrecisionScan - I've never owned a Photosmart!
Ken
Ken Durling [EMAIL PROTECTED] wrote:
If you're resizing an image from 3000 pixels in the width to
750 pixels, you're throwing away 75% of the data!
Aha, okay, see my other reply. I'm slowly coming out of the fog here.
So what's the most lossless way to get my 30MB TIFF file to the size
I
If you're making web images, the dpi for the screen is 72dpi.
End of story.
I'd suggest more like 100dpi these days. The Mac used to maintain 72dpi
simply by specific monitor/video card settings, but I don't know if they
still do that today.
On Mon, 22 Oct 2001 19:12:10 +1000, you wrote:
I try to keep my jpeg files inside 50K for general web use. You can
make quite reasonably sized images on the screen that as a file are inside
that limit. Waiting for larger files to download gets boring, and people on
the web tend to have short
On Mon, 22 Oct 2001 19:12:10 +1000, you wrote:
If you're making web images, the dpi for the screen is 72dpi. End of story.
Right, but scan at 72 dpi and you get crap. One day I'll understand
all this. ;-)
Ken
On Mon, 22 Oct 2001 12:39:14 -0700, you wrote:
Right, but scan at 72 dpi and you get crap. One day I'll understand
all this. ;-)
Hold on - thanks to you all, maybe I DO understand this. If scanned
at 72 dpi, even a 4x6 print would need quite a bit of interpolation to
get it up to a good
On Mon, 22 Oct 2001 15:49:22 -0400, you wrote:
Hold on - thanks to you all, maybe I DO understand this. If scanned
at 72 dpi, even a 4x6 print would need quite a bit of interpolation to
get it up to a good screen size, ergo crap.Is that correct?
No, not interpolation. Interpolation
I guess I'm missing the point here. If I were to scan even a 4x6
print at 72 dpi, and then want to display it anything larger than
288x432 pixels, wouldn't interpolation be necessary? Even more with a
slide or a negative?
But you wouldn't scan at 72dpi if you wanted larger images (pixel
On Mon, 22 Oct 2001 16:08:40 -0400, you wrote:
I guess I'm missing the point here. If I were to scan even a 4x6
print at 72 dpi, and then want to display it anything larger than
288x432 pixels, wouldn't interpolation be necessary? Even more with a
slide or a negative?
But you wouldn't
I'm still not entirely sure why high
res scans look better on a screen only capable of displaying 72dpi.
I assume you mean when you scan them at 27xx and then downsize them to
72dpi, that comes out far better than scanning them AT 72dpi? That's easy,
if that's the case. The PS software does
Ken Durling wrote:
Right, but scan at 72 dpi and you get crap. One day I'll understand
all this. ;-)
My advice is to ignore any references to dpi when scanning for the web.
I once had trouble grasping the concepts but Wayne Fultons site
www.scantips.com was a big help. In particular look
[EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Monday, October 22, 2001 2:47 PM
Subject: Re: filmscanners: RE: filmscanners: Re: Hello, thanks, and more.
| On Mon, 22 Oct 2001 12:39:14 -0700, you wrote:
|
| Right, but scan at 72 dpi and you get crap. One day I'll understand
| all
dimensions of the image only, e.g.
480x640 or whatever.
Maris
- Original Message -
From: Ken Durling [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Monday, October 22, 2001 2:39 PM
Subject: Re: filmscanners: RE: filmscanners: Re: Hello, thanks, and more.
| On Mon, 22 Oct 2001 19:12:10
.
Maris
- Original Message -
From: Ken Durling [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Monday, October 22, 2001 3:08 PM
Subject: Re: filmscanners: RE: filmscanners: Re: Hello, thanks, and more.
| On Mon, 22 Oct 2001 15:49:22 -0400, you wrote:
|
|
| Hold on - thanks to you all, maybe
Austin Franklin wrote:
Hold on - thanks to you all, maybe I DO understand this. If scanned
at 72 dpi, even a 4x6 print would need quite a bit of interpolation to
get it up to a good screen size, ergo crap.Is that correct?
No, not interpolation. Interpolation ADDS data. Decimation
Maris V. Lidaka, Sr. wrote:
Screen dpi is not necessarily 72dpi - it depends on the size of the screen and what
resolution you set your monitor to - consider a 17 monitor at 600x800 pixels v. set
at 1200x1600 pixels - the second will have double the dpi of the first.
Ignore dpi for web use
Your scanner software is probably scanning at full resolution then
downsampling to meet the output specs you gave it. This is actually
a good thing when implemented properly because it makes the UI easy:
just tell it what results you want and it does all the calculating
and manipulating
We
use a 42 bit Microtek Scanmaker X12 USL scanner, ant
it works well. On our old, cheaper 24 bit Umax we could not do
this.On that one, we needed to scan at full resolution and
then convert in Photoshop.
Exactly what I was saying. There is no set rule which is better for any
Hold on - thanks to you all, maybe I DO understand this. If scanned
at 72 dpi, even a 4x6 print would need quite a bit of interpolation to
get it up to a good screen size, ergo crap.Is that correct?
No, not interpolation. Interpolation ADDS data. Decimation
removes data,
Austin wrote:
I'd suggest more like 100dpi these days. The Mac used
to maintain 72dpi simply by specific monitor/video
card settings, but I don't know if they still do that today.
I was giving a rule of thumb for the majority of computer users not for
power users like those with film
Bill wrote:
Your scanner software is probably scanning at
full resolution then downsampling to meet the
output specs you gave it.
This sort of thing has been stated a number of times recently. I can't
really be sure for any scanner other than mine, but the choice of resolution
*does* make
AFAIK digital cameras produce files which are set to 72 dpi. Can anyone
who has one check this? I know it's been driving my brother nuts
when people
send digicam pics at screen resolutions and expect him to print them in
a magazine!
My Fuji 4700 has the file set to 300PPI...at 2400 x
Ken wrote:
Right, but scan at 72 dpi and you get crap.
Not off a print! :)
One day I'll understand all this. ;-)
It's a matter of getting your head around the resolutions of different devices
and media.
Rob
Rob Geraghty [EMAIL PROTECTED]
http://wordweb.com
Fine by me - you just have to know how to work out the math (which you do).
Maris
- Original Message -
From: SKID Photography [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Monday, October 22, 2001 6:13 PM
Subject: Re: filmscanners: RE: filmscanners: Re: Hello, thanks, and more
Ken wrote:
Hold on - thanks to you all, maybe I DO understand this. If scanned
at 72 dpi, even a 4x6 print would need quite a bit of interpolation to
get it up to a good screen size, ergo crap.Is that correct?
6x4 at 72dpi gives you 432 x 238 pixels. That's half of an 800x600 pixel
screen.
HI all -
And thanks very much! Whew, I've read through the posts 3 times now,
and the two immediate questions that are coming up are:
1) Bits. I need some clarification on what the siginificance of all
the different bit-rates are about for color. For example, one person
mentioned that
1) Bits. I need some clarification on what the siginificance of all
the different bit-rates are about for color.
You don't mean rates. Rate is a measure of speed (or periodicity)...and
doesn't apply here.
For example, one person
mentioned that there is no real advantage in 16-bit over
Ken wrote:
1) Bits. I need some clarification on what the siginificance
of all the different bit-rates are about for color.
[snip]
The Canon software only offers scanning in 24-bit color
AFAIK the 2710 produces more than 24 bits RGB at the A/D. 42 maybe? If
you're using something like
On Sun, 21 Oct 2001 22:15:16 -0700, I wrote:
For example, Photo House offers a
choice of Interchange Format (JPEG/JFIF) ;
Oops, left out the other choice, which I just noticed, which is TIFF
JPEG (JTIF). Is that something like the TIFF LZ compression you have
been mentioning? When might I
On Mon, 22 Oct 2001 01:05:24 -0400, you wrote:
That is a case where you certainly can try it. I would suggest trying both
methods, and see which works better for you. Some scanners do a fantastic
job at giving you great scans at reduced DPI, and others are quite bad.
Only through a test of
Comments are below:
Maris
- Original Message -
From: Ken Durling [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Sunday, October 21, 2001 10:53 PM
Subject: filmscanners: Re: Hello, thanks, and more.
| HI all -
|
| And thanks very much! Whew, I've read through the posts 3 times now
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