scanning documents


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M

Miss Perspicacia Tick

wayne said:
for what purpose best overall would be jpg

Wayne
A remark like that shows your complete ignorance of graphic file formats and
scanning techniques. JPG is hardly ever the best format - it is heavily
compressed for a start; Every time you resize a JPG a little more data is
lost - its only use is for posting to newsgroups or emailing (and even then
GIF is preferable). The "best overall" to use your words, is TIF. It is
lossless (even when compressed) and provides the best quality - you can
resize it and it will *NOT* pixellate. You can prove this yourself. Take the
same picture and save it twice - once as a JPG and again as a TIF. Blow both
up to 1000% and compare. Which format looks most like the original image?

I rest my case.
 
T

Tom

Miss Perspicacia Tick said:
A remark like that shows your complete ignorance of graphic file formats and
scanning techniques. JPG is hardly ever the best format - it is heavily
compressed for a start; Every time you resize a JPG a little more data is
lost - its only use is for posting to newsgroups or emailing (and even then
GIF is preferable). The "best overall" to use your words, is TIF. It is
lossless (even when compressed) and provides the best quality - you can
resize it and it will *NOT* pixellate. You can prove this yourself. Take the
same picture and save it twice - once as a JPG and again as a TIF. Blow both
up to 1000% and compare. Which format looks most like the original image?

I rest my case.
Well, you're wrong, tif format makes the file 5x+ bigger than the jpeg, and it pixilated as more than the jpeg. First of all, it is how the image is created and saved. You cannot make the image pixelate more or less in any format; it is simply saved RAW as the DPI ratio used to create the image, and it remains the same whether or not when changed to another compression.

(Note, when using Windows Picture and Fax Viewer, it pixelates very little in jpeg format, whereas it does a great deal in tif format)

example:
http://home.insightbb.com/~guesswho192/example.gif

I rest my case
 
S

scanman

Well, you're wrong, tif format makes the file 5x+ bigger than the jpeg, and it pixilated as more than the jpeg. First of all, it is how the image is created and saved. You cannot make the image pixelate more or less in any format; it is simply saved RAW as the DPI ratio used to create the image, and it remains the same whether or not when changed to another compression.

(Note, when using Windows Picture and Fax Viewer, it pixelates very little in jpeg format, whereas it does a great deal in tif format)

example:
http://home.insightbb.com/~guesswho192/example.gif

I rest my case

Sorry to correct everyone here, but if it's a document you want
to scan, you need to save it as some type of text file, not as a TIFF
or JPEG file, as those are picture files, which is why you get the
jaggies (pixelation). Your scanner should have come with some type
of Optical Character Recognition (OCR) software. This is the software
you need to run when scanning a document, not the usual scanning
software that you run when scanning a picture. The OCR software will
recognize the text and create a text document for you.(like a Word
document).
Keep in mind that saving it as a TIFF or JPEG file will result in
the file becoming a picture file. That means that you won't be able
to edit text in it, like you would if you saved it as a text file. If
you scan a letter, for example, you would want to be able to edit the
text in it. You couldn't do that if you saved it as a TIFF or JPEG
file.
Oh, and as for which is better TIFF or JPEG, well, that all
depends on what you are going to do with the scanned image. A
PhotoShop (PSD) file, a Bitmap file, a PNG file, or a TIFF file will
all do an excellent job of retaining the original scanned information,
but they are all large files. A JPEG file is a lossy format, and it
should only be used to save the image after all the editing has been
done to it. Once you are satisfied with the edited picture, then you
can save it as a JPEG file.....I prefer to save it at a 15%
compression value, or as they say, at a "Q" of 85. Some people think
that 80 is okay, but I like to have the extra 5%. Comparing a JPEG
that's been saved at 85 will look identical to the original, be it a
TIFF or whatever. Saving it at a higher "Q" over 85 will not improve
the picture quality, it will only increase the filesize.
Sorry, but I guess that's more that you wanted to know.
 
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S

Sharon F

Sorry to correct everyone here, but if it's a document you want
to scan, you need to save it as some type of text file, not as a TIFF
or JPEG file, as those are picture files, which is why you get the
jaggies (pixelation). Your scanner should have come with some type
of Optical Character Recognition (OCR) software. This is the software
you need to run when scanning a document, not the usual scanning
software that you run when scanning a picture. The OCR software will
recognize the text and create a text document for you.(like a Word
document).
Keep in mind that saving it as a TIFF or JPEG file will result in
the file becoming a picture file. That means that you won't be able
to edit text in it, like you would if you saved it as a text file. If
you scan a letter, for example, you would want to be able to edit the
text in it. You couldn't do that if you saved it as a TIFF or JPEG
file.
Oh, and as for which is better TIFF or JPEG, well, that all
depends on what you are going to do with the scanned image. A
PhotoShop (PSD) file, a Bitmap file, a PNG file, or a TIFF file will
all do an excellent job of retaining the original scanned information,
but they are all large files. A JPEG file is a lossy format, and it
should only be used to save the image after all the editing has been
done to it. Once you are satisfied with the edited picture, then you
can save it as a JPEG file.....I prefer to save it at a 15%
compression value, or as they say, at a "Q" of 85. Some people think
that 80 is okay, but I like to have the extra 5%. Comparing a JPEG
that's been saved at 85 will look identical to the original, be it a
TIFF or whatever. Saving it at a higher "Q" over 85 will not improve
the picture quality, it will only increase the filesize.
Sorry, but I guess that's more that you wanted to know.
It's a good recap of the options for document files. Part of the decision
of what format to use will rely on why the document is being scanned.

If an electronic copy is needed, an image file will give an exact duplicate
of the original (plus a few jagged pixels depending on settings). If
there's a need to work with the text, OCR or software designed to scan
forms are a better alternative.
 

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