scanned images soft – why ?

F
Posted By
Frank
Sep 30, 2004
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Why are scanned images invariably soft (out-of-focus)? It doesnt matter if the original is film (neg or transparency) or print.Can you explain it ?

I have a good film scanner (Polaroid 120) and Silverfast Ai software (which has a focus on/off).
My flatbed is somewhat older (Microtek Scanmaker III with Scanwizard) but still decent.

When I open the images in Photoshop I’m always disappointed in how ‘soft’ they are and they Always need sharpening applied.

Apparently ‘it’s a fact of life’ but why ?

How to Master Sharpening in Photoshop

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TT
Tom Thomas
Sep 30, 2004
"frankg" wrote:

Why are scanned images invariably soft (out-of-focus)? It doesnt matter if the original is film (neg or transparency) or print.Can you explain it ?

— snip —

This is more related to the scanner groups than Photoshop but here’s a stab at it.

Essentially any analog to digital conversion loses fidelity because the digital copy is produced from samples rather than a continuous signal. In the case of a scanner, it’s samples at approximately 1,000 per inch are not as sharp as the continuous tones produced by a good camera lens [1]. This is analagous to digitally sampled music (CD) compared to analog recording (audio tape or vinyl). The analog version contains many subtle overtones and inflections which are lost in the "stair step" effect of digital sampling. We accept audio CD as a medium because of its compactness, portability and durability — not because it produces better sound.

You might enjoy looking at Wayne Fulton’s web site, www.scantips.com . He provides a lot of information on why scanners behave as they do, and how to compensate.

[1] Information paraphrased from the aforementioned www.scantips.com .

——————————-
Tom

Unsolicited advertisements cheerfully ignored.
S
Stephan
Sep 30, 2004
"frankg" wrote in message
Why are scanned images invariably soft (out-of-focus)? It doesnt matter if the original is film (neg or transparency) or print.Can you explain it ?
I have a good film scanner (Polaroid 120) and Silverfast Ai software
(which
has a focus on/off).
My flatbed is somewhat older (Microtek Scanmaker III with Scanwizard) but still decent.

When I open the images in Photoshop I’m always disappointed in how ‘soft’ they are and they Always need sharpening applied.

Apparently ‘it’s a fact of life’ but why ?

Do you check sharpness with your picture open a 100% of its size?

Stephan
F
Frank
Sep 30, 2004
yes


xx
"Stephan" wrote in message
"frankg" wrote in message
Why are scanned images invariably soft (out-of-focus)? It doesnt matter
if
the original is film (neg or transparency) or print.Can you explain it ?
I have a good film scanner (Polaroid 120) and Silverfast Ai software
(which
has a focus on/off).
My flatbed is somewhat older (Microtek Scanmaker III with Scanwizard)
but
still decent.

When I open the images in Photoshop I’m always disappointed in how
‘soft’
they are and they Always need sharpening applied.

Apparently ‘it’s a fact of life’ but why ?

Do you check sharpness with your picture open a 100% of its size?
Stephan

J
jjs
Oct 1, 2004
"Stephan" wrote in message
Do you check sharpness with your picture open a 100% of its size?

Well, of course. And they just suck. The scanners that we modestly incomed people can afford just suck. They ALL need a USM treatment because the ‘tween shit is just terrible.

USE FILM.
H
Hecate
Oct 1, 2004
On Thu, 30 Sep 2004 14:18:59 -0400, "frankg"
wrote:

Why are scanned images invariably soft (out-of-focus)? It doesnt matter if the original is film (neg or transparency) or print.Can you explain it ?
Funny, I don’t have that problem with my Minolta 5400…



Hecate – The Real One

veni, vidi, reliqui
S
Stephan
Oct 1, 2004
"Hecate" wrote in message
On Thu, 30 Sep 2004 14:18:59 -0400, "frankg"
wrote:

Why are scanned images invariably soft (out-of-focus)? It doesnt matter
if
the original is film (neg or transparency) or print.Can you explain it ?
Funny, I don’t have that problem with my Minolta 5400…
Same here, I have an older slow and loud scanner but the images are razor sharp.

Stephan
J
jjs
Oct 1, 2004
"Stephan" wrote in message

Same here, I have an older slow and loud scanner but the images are razor sharp.

It is possible that your scanning program is applying USM, and/or your critical requisites are weak.
S
Scraphead
Oct 1, 2004
I have a canon 5000f that works really well. What kind of scanner are you talking about?

"frankg" wrote in message
Why are scanned images invariably soft (out-of-focus)? It doesnt matter if the original is film (neg or transparency) or print.Can you explain it ?
I have a good film scanner (Polaroid 120) and Silverfast Ai software
(which
has a focus on/off).
My flatbed is somewhat older (Microtek Scanmaker III with Scanwizard) but still decent.

When I open the images in Photoshop I’m always disappointed in how ‘soft’ they are and they Always need sharpening applied.

Apparently ‘it’s a fact of life’ but why ?

MR
Mike Russell
Oct 1, 2004
jjs wrote:
"Stephan" wrote in message
Do you check sharpness with your picture open a 100% of its size?

Well, of course. And they just suck. The scanners that we modestly incomed people can afford just suck. They ALL need a USM treatment because the ‘tween shit is just terrible.

To paraphrase young Dr. Frankenstein,

USM, USM,
There’s no escaping USM!

But, unlike the fate of Gene Wilder’s character, there’s nothing wrong with Unsharp Mask (USM). It’s a practical and mathematically valid way to make resampled images look better. Even our own eyes use a biological variation of USM to enhance edges.

Conventional printing and enlargement had similar techniques for sharpening that used optics and chemistry. For example a condenser based enlarger would print a very harsh, grainy image. A diffuser placed in the enlarger would produce a softer, but still optically sharp image. Different methods of development could enhance or reduce the contrast and apparent sharpness of the image.

The name USM came from film based photography, using a blurred negative (unsharp mask) sandwiched with the original to create sharpness. Photoshop, and other programs, have "digitized" the methods used by conventional photography.

USE FILM.

There ain’t nothin like a chrome, nothin in the world. But unless you are using conventional development all the way to the final print, and few people are these days, pretty much every pixel you capture on film will be USM’ed at almost every stage in its digital life cycle, exactly as if it were a digital image.

When negs and chromes scanned and digitally printed yes, Virginia, they are will be resampled and sharpened at some point in that process. Drum scanners, still the best scanner technology, have operator controlled USM built into the electronics that sharpens the image as it is scanned, and the Printer RIP does similar resampling and sharpening of image color values as it figures out where the final dots of color should go.

But you need not look far at all to find USM. Our eyes, in a way, defined not only the CRT’s we use to view images, but the underlying algorithms that we use to process those images for our own convenience. Our own visual apparatus uses USM-style edge enhancement to sharpen the retinal image. So, you see, resistance is futile, there is no escaping USM. —

Mike Russell
www.curvemeister.com
www.geigy.2y.net

How to Master Sharpening in Photoshop

Give your photos a professional finish with sharpening in Photoshop. Learn to enhance details, create contrast, and prepare your images for print, web, and social media.

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