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Message |
Franklin
Guest
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 Posted:
Sun Nov 13, 2005 8:19 am Post subject:
Acdsee shows whitespace as gray |
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I scanned some text documents and created JPG files.
(a) If I open the jpegs in Irfanview and print then the documents
come out normally as black text on a white background.
(b) If I open the same jpegs in my old ACDSee 3.1 then the documents
come out as black print on a *LIGHT GRAY* background.
In the past ACDSee 3.1 was fine to print jpegs of a text document.
What is happening? The main system changes have been installing XP
SP2 and reinstalling ACDsee 3.1
SOME MORE DETAILS
There are not many settings for ACDSee 3.1 and almost none have
anything to do with picture quality. The scans were done by
launching ACDSee and then calling TWAIN from there.
GIFs print as black on white. JPEGS are visibly black on GRAY. |
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tacit
Guest
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| Posted:
Sun Nov 13, 2005 8:25 am Post subject:
Re: Acdsee shows whitespace as gray |
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In article <970D17A88A77B71F3M4@66.250.146.159>,
Franklin <no_thanks@mail.com> wrote:
| Quote: | I scanned some text documents and created JPG files.
|
Issues with ACDSee aside, is there a reason you chose to save the files
as JPEG instead of some other format? You may have made a mistake by
saving them as JPEG.
JPEG is a "lossy" format. That means the quality of any scan you save as
a JPEG is degraded in order to make the file smaller on disk. JPEG is
especially bad on text, making it (or anything else with hard, straight
lines) "blurry."
JPEG was invented for situations where file size is very important and
image quality is not important. You should never save any scan as a JPEG
unless there is some clear, specific reason why it *has* to be JPEG and
no other format will work.
--
Art, photography, shareware, polyamory, literature, kink:
all at http://www.xeromag.com/franklin.html |
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Greg N.
Guest
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| Posted:
Sun Nov 13, 2005 9:36 pm Post subject:
Re: Acdsee shows whitespace as gray |
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tacit wrote:
| Quote: | JPEG is a "lossy" format. That means the quality of any scan you save as
a JPEG is degraded in order to make the file smaller on disk. JPEG is
especially bad on text, making it (or anything else with hard, straight
lines) "blurry."
|
It's all a function of the compression level you choose. If you use
mild compression, your text will be just fine, while the resulting JPG
is still only a fraction of the size of the corresponding TIFF.
| Quote: | JPEG was invented for situations where file size is very important and
image quality is not important.
|
If you're dealing with a collection of a few thousand scanned text
documents, size may matter a lot.
| Quote: | You should never save any scan as a JPEG
unless there is some clear, specific reason why it *has* to be JPEG and
no other format will work.
|
More often than not, scanning is for document archival, where image
quality is not really important. For text documents, my take is, as
long as it's well readable and printable, it's OK to store it as JPG.
--
Gregor's Motorradreisen:
http://hothaus.de/greg-tour/ |
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Scruff
Guest
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| Posted:
Sun Nov 13, 2005 10:31 pm Post subject:
Re: Acdsee shows whitespace as gray |
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Why twain them through Acdsee when you can do an infinitely better job
through
PhotoShop.
And if you don't have photoshop, why are you posting here?
"Franklin" <no_thanks@mail.com> wrote in message
news:970D17A88A77B71F3M4@66.250.146.159...
| Quote: | I scanned some text documents and created JPG files.
(a) If I open the jpegs in Irfanview and print then the documents
come out normally as black text on a white background.
(b) If I open the same jpegs in my old ACDSee 3.1 then the documents
come out as black print on a *LIGHT GRAY* background.
In the past ACDSee 3.1 was fine to print jpegs of a text document.
What is happening? The main system changes have been installing XP
SP2 and reinstalling ACDsee 3.1
SOME MORE DETAILS
There are not many settings for ACDSee 3.1 and almost none have
anything to do with picture quality. The scans were done by
launching ACDSee and then calling TWAIN from there.
GIFs print as black on white. JPEGS are visibly black on GRAY.
|
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tacit
Guest
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| Posted:
Mon Nov 14, 2005 2:31 am Post subject:
Re: Acdsee shows whitespace as gray |
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In article <dl7mhj$qta$1@online.de>, "Greg N." <yodel_dodel@yahoo.com>
wrote:
| Quote: | More often than not, scanning is for document archival, where image
quality is not really important. For text documents, my take is, as
long as it's well readable and printable, it's OK to store it as JPG.
|
Actually, if you want the highest possible quality AND small files, the
best approach is to scan text as a one-bit bitmap, rather than as
grayscale, then save the bitmap as a TIFF.
If the original source is bilevel--no shades of gray--then it will print
better if it is scanned as a high-resolution bitmap. What's more, the
file will be smaller than a JPEG grayscale file, and it will print more
cleanly. If it's saved as an LZW-compressed TIFF, the file size will be
very small indeed, yet it will have absolutely none of the degradation
of JPEG.
Scan color originals in color. Scan grayscale originals in grayscale.
Scan black and white originals as bitmap.
--
Art, photography, shareware, polyamory, literature, kink:
all at http://www.xeromag.com/franklin.html |
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Greg N.
Guest
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| Posted:
Mon Nov 14, 2005 6:24 am Post subject:
Re: Acdsee shows whitespace as gray |
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tacit wrote:
| Quote: | Actually, if you want the highest possible quality AND small files, the
best approach is to scan text as a one-bit bitmap, rather than as
grayscale, then save the bitmap as a TIFF.
|
1-bit images are a remnant of the past, from the times 20 years ago when
efficient jpeg compression was not the the de-facto norm yet.
| Quote: | If the original source is bilevel--no shades of gray--then it will print
better if it is scanned as a high-resolution bitmap. What's more, the
file will be smaller than a JPEG grayscale file, and it will print more
cleanly. If it's saved as an LZW-compressed TIFF, the file size will be
very small indeed, yet it will have absolutely none of the degradation
of JPEG.
|
These days, not many people find bi-level images very useful any more,
because because the notion of "bilevel - no shades of gray" does not
really exist in practice. You'll have no anti-aliasing effect without
an appropriate range of grey levels. Characters will become jagged.
Images of text may become hard to read or plain unusable if the type
is small or if character edges are not well defined.
The only way around this would be to use very high resolution, which
defeats the purpose of bi-evel representation, namely image file
compactness. My take is, forget about bi-level representation, it
stinks for most practical applications.
| Quote: | Scan color originals in color. Scan grayscale originals in grayscale.
Scan black and white originals as bitmap.
|
Bitmap versus color or grayscale? What do you mean by that? Bitmap is
a file format that can represent any color depth you chose, from
bi-level to RGB.
--
Gregor's Motorradreisen:
http://hothaus.de/greg-tour/ |
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tacit
Guest
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| Posted:
Mon Nov 14, 2005 8:26 am Post subject:
Re: Acdsee shows whitespace as gray |
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In article <dl8lfu$e2h$1@online.de>, "Greg N." <yodel_dodel@yahoo.com>
wrote:
| Quote: | These days, not many people find bi-level images very useful any more,
because because the notion of "bilevel - no shades of gray" does not
really exist in practice. You'll have no anti-aliasing effect without
an appropriate range of grey levels. Characters will become jagged.
Images of text may become hard to read or plain unusable if the type
is small or if character edges are not well defined.
|
With low-res images, sure.
But you're making a big, big mistake if you believe that 1-bit bitmaps
are a thing of the past. All laser printers print 1-bit bitmaps. All
imagesetters print 1-bit bitmaps. They are incapable of printing shades
of gray.
Ironically, 1-bit images print far better to a laser printer or an
imagesetter than grayscale images do, because such devices produce
shades of gray by halftoning--printing patterns of dots to simulate
levels of gray--and a 1-bit image prints with no halftoning, whereas a
grayscale image prints with little halftone dots all around the edges of
the characters.
A bitmap looks jaggy on a computer screen, but prints far better than a
grayscale image for this reason.
It seems to me that you are likely inexperienced with prepress and with
digital output, else you would not be saying things like "1-bit images
are a remnant of the past."
--
Art, photography, shareware, polyamory, literature, kink:
all at http://www.xeromag.com/franklin.html |
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