Best common file format to use to create PDFs?

Z
Posted By
Zak
May 30, 2006
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"Zak" schreef in bericht
I use XP.

I scan a document to a graphics file (eg jpg, gif, bmp, etc) Then I make a PDF from the graphics file.

I see that if I save a large bitmap (BMP) and then create a PDF then the PDF is no bigger than if I had compressed the image to a GIF and used that to create a PDF file.

In order to preserve quality, avoid artefacts and interference patterns, would it be better to save to a large and detailed intermediate file like a BMP (or even a jpeg) or to save to a small lossless file like a GIF or TIF?

On 26 May 2006, Nils wrote:
Afaik, GIF is not used as a graphical format inside PDF. It is probably compressed as a "TIFF" with Cittfax or LZW compression. "TIFF" is between brackets, because the embedded stream is also not a complete TIFF file, just contains the compressed graphics and some extra information like scansize, colordepth, color channels, etc.

What happens under the hood in your PDF creation really depends on the PDF engine you’re using. Many engines actually resize your graphics to match the PDF DPI resolution. If you’re an experienced programmer you could try to generate the PDF yourself, with the images in full resolution. The PDF specification is open and can be found on the Adobe website.

Nils

Hi Nils and others. I understand now that when I create a PDF from a image file that the format of the image file is not used inside the PDF. Instead some other format is used in the PDF (which Nils kindly suggests may be a specialized form of TIFF).

It is this conversion from my image file format to the internal PDF format which I want to be done smoothly. I am on XP and I am wondering if it is better to start with a GIF or a JPG or BMP or whatever to feed into my PDF creation utility.

I should say that I am starting with a hard copy of a document created on a word processor. I want to avoid artefacts, unecessarily jagged lines, moire effects and all that stuff which might come from transforming from an "awkward2 image format to a PDF.

My PDFs will be for public distribution. I have preferred to scan to a GIF file rather than a TIFF because I have assumed that when I circulate the basic image file among certain people that the best balance between image size and the best chance of them being able to see the file is a GIF.

To me TIFF feels a bit specialized. For example, I never see a web page with TIFF images but I see lots of pages with GIFs.

Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format! The Wikipedia says documents are often scanned to TIFF group 4 but is that something which has the best chance of being seen on various PCs in various organisations that I might need to send it to?

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C
CSM1
May 30, 2006
"Zak" wrote in message
"Zak" schreef in bericht
I use XP.

I scan a document to a graphics file (eg jpg, gif, bmp, etc) Then I make a PDF from the graphics file.

I see that if I save a large bitmap (BMP) and then create a PDF then the PDF is no bigger than if I had compressed the image to a GIF and used that to create a PDF file.

In order to preserve quality, avoid artefacts and interference patterns, would it be better to save to a large and detailed intermediate file like a BMP (or even a jpeg) or to save to a small lossless file like a GIF or TIF?

On 26 May 2006, Nils wrote:
Afaik, GIF is not used as a graphical format inside PDF. It is probably compressed as a "TIFF" with Cittfax or LZW compression. "TIFF" is between brackets, because the embedded stream is also not a complete TIFF file, just contains the compressed graphics and some extra information like scansize, colordepth, color channels, etc.

What happens under the hood in your PDF creation really depends on the PDF engine you’re using. Many engines actually resize your graphics to match the PDF DPI resolution. If you’re an experienced programmer you could try to generate the PDF yourself, with the images in full resolution. The PDF specification is open and can be found on the Adobe website.

Nils

Hi Nils and others. I understand now that when I create a PDF from a image file that the format of the image file is not used inside the PDF. Instead some other format is used in the PDF (which Nils kindly suggests may be a specialized form of TIFF).

It is this conversion from my image file format to the internal PDF format which I want to be done smoothly. I am on XP and I am wondering if it is better to start with a GIF or a JPG or BMP or whatever to feed into my PDF creation utility.

I should say that I am starting with a hard copy of a document created on a word processor. I want to avoid artefacts, unecessarily jagged lines, moire effects and all that stuff which might come from transforming from an "awkward2 image format to a PDF.

You can create a very clean PDF directly from a Microsoft Word Document (.doc).
There are programs that act like a printer that creates a PDF, just by "printing a PDF".

PDF Create! is one such program.

Just search Google for "microsoft word print pdf" without the quotes. You will get lots of responses.


CSM1
http://www.carlmcmillan.com


My PDFs will be for public distribution. I have preferred to scan to a GIF file rather than a TIFF because I have assumed that when I circulate the basic image file among certain people that the best balance between image size and the best chance of them being able to see the file is a GIF.

To me TIFF feels a bit specialized. For example, I never see a web page with TIFF images but I see lots of pages with GIFs.
Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format! The Wikipedia says documents are often scanned to TIFF group 4 but is that something which has the best chance of being seen on various PCs in various organisations that I might need to send it to?

CSM1
http://www.carlmcmillan.com
Z
Zak
May 30, 2006
On 30 May 2006, CSM1 wrote:

You can create a very clean PDF directly from a Microsoft Word Document (.doc).
There are programs that act like a printer that creates a PDF, just by "printing a PDF".

PDF Create! is one such program.

Just search Google for "microsoft word print pdf" without the quotes. You will get lots of responses.

The documents are not written by me. They have been sent to me so they are in hard copy form and need scanning.
JV
John V-Tracker
May 30, 2006
Why not let a program like PDF-Tools take care of the problems for you – this will scan direct to PDF for you without the intermediate image process – all you need to do is make you decision’s regarding optimisation/compression.

you can try it here within the PDF-XChange PRO package (not standard or Lite versions) – until licensed you will get demo watermarks in the top right/left corner of each page which do add about 4kb to each page.

http://www.docu-track.com/downloads/users/


Best Regards

John Verbeeten
Tracker Software Products
PDF-XChange & SDK, Image-XChange SDK,
PDF-Tools & SDK, TIFF-XChange & SDK, DocuTrack.
Email :
Support: http://www.docu-track.com/forum/index.php
Web site : http://www.docu-track.com
"Zak" wrote in message
"Zak" schreef in bericht
I use XP.

I scan a document to a graphics file (eg jpg, gif, bmp, etc) Then I make a PDF from the graphics file.

I see that if I save a large bitmap (BMP) and then create a PDF then the PDF is no bigger than if I had compressed the image to a GIF and used that to create a PDF file.

In order to preserve quality, avoid artefacts and interference patterns, would it be better to save to a large and detailed intermediate file like a BMP (or even a jpeg) or to save to a small lossless file like a GIF or TIF?

On 26 May 2006, Nils wrote:
Afaik, GIF is not used as a graphical format inside PDF. It is probably compressed as a "TIFF" with Cittfax or LZW compression. "TIFF" is between brackets, because the embedded stream is also not a complete TIFF file, just contains the compressed graphics and some extra information like scansize, colordepth, color channels, etc.

What happens under the hood in your PDF creation really depends on the PDF engine you’re using. Many engines actually resize your graphics to match the PDF DPI resolution. If you’re an experienced programmer you could try to generate the PDF yourself, with the images in full resolution. The PDF specification is open and can be found on the Adobe website.

Nils

Hi Nils and others. I understand now that when I create a PDF from a image file that the format of the image file is not used inside the PDF. Instead some other format is used in the PDF (which Nils kindly suggests may be a specialized form of TIFF).

It is this conversion from my image file format to the internal PDF format which I want to be done smoothly. I am on XP and I am wondering if it is better to start with a GIF or a JPG or BMP or whatever to feed into my PDF creation utility.

I should say that I am starting with a hard copy of a document created on a word processor. I want to avoid artefacts, unecessarily jagged lines, moire effects and all that stuff which might come from transforming from an "awkward2 image format to a PDF.
My PDFs will be for public distribution. I have preferred to scan to a GIF file rather than a TIFF because I have assumed that when I circulate the basic image file among certain people that the best balance between image size and the best chance of them being able to see the file is a GIF.

To me TIFF feels a bit specialized. For example, I never see a web page with TIFF images but I see lots of pages with GIFs.
Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format! The Wikipedia says documents are often scanned to TIFF group 4 but is that something which has the best chance of being seen on various PCs in various organisations that I might need to send it to?
S
siegman
May 30, 2006
In article ,
Zak wrote:

The documents are not written by me. They have been sent to me so they are in hard copy form and need scanning.

If the documents are in single-sheet form and can be fed thru a sheet-feed scanner, the fairly new Fujitsu "ScanSnap" can automatically produce PDF output (or other formats, at user’s option).

It’s a bit pricey (circa $400) but it’s a pretty nice unit, small, fast, easy to use, can do both sides at once, auto-select for B&W or color, and so on.
DW
Dances With Crows
May 30, 2006

["Followup-To:" header set to comp.periphs.scanners.]
On Tue, 30 May 2006 16:30:29 +0100, Zak staggered into the Black Sun and said:
"Zak" schreef in bericht
On 26 May 2006, Nils wrote:
In order to preserve quality, avoid artefacts and interference patterns, would it be better to save to a large and detailed intermediate file like a BMP (or even a jpeg) or to save to a small lossless file like a GIF or TIF?
Afaik, GIF is not used as a graphical format inside PDF. It is probably compressed as a "TIFF" with Cittfax or LZW compression. "TIFF" is between brackets, because the embedded stream is also not a complete TIFF file.

What happens under the hood in your PDF creation really depends on the PDF engine you’re using. Many engines actually resize your graphics to match the PDF DPI resolution. If you’re an experienced programmer you could try to generate the PDF yourself

Zak is obviously not a programmer, let alone an experienced one. Using PDFlib from C isn’t that difficult if you have some experience in C, though.

The PDF specification is open and can be found on the Adobe website.

And creating a PDF using only the spec would take a bunch of experienced programmers a while. The PDF spec is really, really complex. Its complexity is one reason why PDFlib and ps2pdf and OpenOffice’s "print to PDF" functionality exist.

I understand now that when I create a PDF from a image file that the format of the image file is not used inside the PDF. Instead some other format is used in the PDF (which Nils kindly suggests may be a specialized form of TIFF).

Using tiff2ps -> ps2pdf says that a grayscale TIFF ends up converted to a stream object that can be decoded by the FlateDecode filter. YPDFEngineMV, obviously.

It is this conversion from my image file format to the internal PDF format which I want to be done smoothly. I am wondering if it is better to start with a GIF or a JPG or BMP or whatever to feed into my PDF creation utility.

Depends on what you want. Get a good scan, and convert it to black-and-white if you can do that without losing important info; that’ll make the PDF smaller. JPEG may introduce artifacts, so you probably don’t want to use that. TIFF G4 and TIFF LZW are lossless, so you may want to use those.

I should say that I am starting with a hard copy of a document created on a word processor.

Yuck. The original WordPerfect or whatever file would’ve been a much better place to start from. PDFs with just text in them tend to be smaller, display faster, and can look good at any zoom level. PDFs made from images take a longer time to display, are larger, and look terrible at high zoom levels.

I have preferred to scan to a GIF file rather than a TIFF because I have assumed that when I circulate the basic image file among certain people that the best balance between image size and the best chance of them being able to see the file is a GIF.

? You’re creating a PDF, not distributing a series of image files.

To me TIFF feels a bit specialized. For example, I never see a web page with TIFF images but I see lots of pages with GIFs.

This is because of Hysterical Raisins in the history of web browsers, and because of Unisys being asses. JPEG compresses better than TIFF-LZW for lossy color images, and smaller images are preferred, especially when you’re on dialup. TIFF-LZW gives the best lossless compression for color images, but TIFF-LZW is usually used where losslessness is more important than file size (like in prepress.) Also, Unisys said they’d sue anyone who made a TIFF-LZW compressor unless they paid Unisys a license fee.[0] These things combined made it so that the earliest GUI browsers didn’t support viewing TIFFs, just JPEGs and GIFs. And this has persisted to the present day… even though TIFF-G4 compresses better than *anything* else, and does so losslessly, iff your image is black-and-white.

Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format! The Wikipedia says documents are often scanned to TIFF group 4 but is that something which has the best chance of being seen on various PCs in various organisations that I might need to send it to?

….what? If somebody can’t figure out how to view a Group4 TIFF, they’re probably computer-illiterate. Anyway, aren’t you making a PDF here? It doesn’t matter what the original image format was if it’s been PDFed. Acrobrat Reader can decode the image data within a PDF, as long as the PDF library/PDF writer/whatever that created that PDF wasn’t smoking crack. Anyway, HTH,

[0] Fortunately, their patent (on a *mathematical method*!) expired a couple of years ago, so all the Free stuff can write LZW now, which is a win for everybody.


Matt G|There is no Darkness in eternity/But only Light too dim for us to see Screw up your courage! You’ve screwed up everything else.
Q
quite
May 30, 2006
Zak wrote:

"Zak" schreef in bericht
I use XP.

I scan a document to a graphics file (eg jpg, gif, bmp, etc) Then I make a PDF from the graphics file.

Never use JPEG for this purpose. GIF and BMP are not the normal choice.
I see that if I save a large bitmap (BMP) and then create a PDF then the PDF is no bigger than if I had compressed the image to a GIF and used that to create a PDF file.

Yes. The image file format isn’t stored in the PDF.
In order to preserve quality, avoid artefacts and interference patterns, would it be better to save to a large and detailed intermediate file like a BMP (or even a jpeg) or to save to a small lossless file like a GIF or TIF?

Absolutely not JPEG. BMP has no advantage over TIFF and GIF has disadvantage.

I don’t really follow your question. since GIF and TIFF use lossless compression, then preserve quality and avoid artefacts and interference patterns, by definition.

You may have the choice of whether to use lossless compression, or not, in making the PDF.
My PDFs will be for public distribution. I have preferred to scan to a GIF file rather than a TIFF because I have assumed that when I circulate the basic image file among certain people that the best balance between image size and the best chance of them being able to see the file is a GIF.

If you are distributing the image file, that may be true. If you are preparing the PDF file from the image file, it is not relevant at all.
To me TIFF feels a bit specialized. For example, I never see a web page with TIFF images but I see lots of pages with GIFs.

That’s because web browsers can display GIF and JPEG images as standard, so web graphics are in those formats. That doesn’t make them in any sense "best".

TIFF is the industry standard format for document scanning, by a very wide margin.
Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format!

These options are not relevant. The PDF file doesn’t include the TIFF information, only the image from the TIFF file.
—————————————-
Aandi Inston
Please support usenet! Post replies and follow-ups, don’t e-mail them.
R
Roger
May 30, 2006
On Tue, 30 May 2006 16:30:29 +0100, Zak wrote:

"Zak" schreef in bericht
I use XP.

I scan a document to a graphics file (eg jpg, gif, bmp, etc) Then I make a PDF from the graphics file.

As far as I can see there really is no best common file format to convert. If it’ll convert it’ll work. However the size of the original file will have a direct bearing on the size of the pdf.

If you are doing something like creating a newsletter, flyer, or Internet distribution then why not use the original doc file?

I handle several newsletters on line and in print.
With Adobe pro any Office and I believe Word Perfect doc can be converted directly to a pdf. However any images in the documents should be of the proper size and resolution for the end media. I’ve had Word docs sent to me that had the full original images with just the physical dimensions set. They were still the original one or two meg images set to a dimension of 2 X 3 inches. These produced nice looking pdfs, but of many megabytes. Having the images set to the proper resolution (300 ppi for print and about 100 ppi for screen) dropped the pdf to less than 100K.

Also not all pdf creators are created equal. About a year ago I tried using open office to convert a word doc and produced one that was about 3 to 4 times the size of one using Adobe Pro. This is fine for printed media, but may (or may not) be a royal pain in the back side for on-line viewing.

For on-line I much prefer HTML rather than pdfs as the HTML will be faster to load and more compact. At least it will if it wasn’t created by saving a Word doc as HTML or using Front Page to create it. Those are huge. OTOH converting to a pdf is faster and much easier and I do use them when the pdfs are relatively small.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
Q
quite
May 30, 2006
Roger wrote:

On Tue, 30 May 2006 16:30:29 +0100, Zak wrote:

"Zak" schreef in bericht
I use XP.

I scan a document to a graphics file (eg jpg, gif, bmp, etc) Then I make a PDF from the graphics file.

As far as I can see there really is no best common file format to convert. If it’ll convert it’ll work. However the size of the original file will have a direct bearing on the size of the pdf.

No. The size of the original will usually have no effect whatsoever, though some PDF creation methods are influenced by it.

With Adobe pro any Office and I believe Word Perfect doc can be converted directly to a pdf.

With Acrobat Pro or Acrobat Standard, any file you can print can be converted directly to a PDF.

. Having the images set to the
proper resolution (300 ppi for print and about 100 ppi for screen) dropped the pdf to less than 100K.

Or, you could use Acrobat options to reduce the resolution. —————————————-
Aandi Inston
Please support usenet! Post replies and follow-ups, don’t e-mail them.
T
Tacit
May 31, 2006
In article ,
Zak wrote:

I should say that I am starting with a hard copy of a document created on a word processor.

Why don’t you just start with the word processor file, and not with a hardcopy at all? Go straight from the word processor file to PDF.

I want to avoid artefacts, unecessarily
jagged lines, moire effects and all that stuff which might come from transforming from an "awkward2 image format to a PDF.
My PDFs will be for public distribution. I have preferred to scan to a GIF file rather than a TIFF because I have assumed that when I circulate the basic image file among certain people that the best balance between image size and the best chance of them being able to see the file is a GIF.

A GIF is almost the worst possible choice to use, because GIF images contain a very small number of colors, and because of this they don’t tend to downsample smoothly.

Use TIFF. Anything that can read a PDF, can read a PDF, period. It does not matter what you start with; once it is turned into a PDF, it is a PDF. However, a TIFF image will downsample and compress smoothly.

To me TIFF feels a bit specialized. For example, I never see a web page with TIFF images but I see lots of pages with GIFs.

That doesn’t mean a GIF is the best format to use for general purposes, however.

Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format!

You do not need to choose any of these. You do not need to compress the TIFF at all.

Scan a TIFF, make a PDF, send out the PDF, you’re done. Or, better yet, do not use your scanner at all. Start with the word processor file, make a PDF–it’ll be smaller and far higher quality. 🙂


Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html
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Z
Zak
May 31, 2006
Snipped and trimmed to context.

I scan a document to a graphics file (eg jpg, gif, bmp, etc) Then I make a PDF from the graphics file.

On 30 May 2006, Aandi Inston wrote:
Never use JPEG for this purpose. GIF and BMP are not the normal choice.

Absolutely not JPEG. BMP has no advantage over TIFF and GIF has disadvantage.

I don’t really follow your question. since GIF and TIFF use lossless compression, then preserve quality and avoid artefacts and interference patterns, by definition.

You may have the choice of whether to use lossless compression, or not, in making the PDF.

I think you are "echoing" what I have just been reading from Dances- With-Crows.

I should explain the artifacts notion i was asking about. If I scan to a GIF which I understand is lossless, then it still has a certain number of "lines" and a certain block size or whatever it is that is inside a GIF. If these blocks and lines do not match up with those used by the image it is converted to inside the PDF then there may be additional irregularities introduced at those places of mismatch.

It’s a bit like memory and a system bus on a motherboard. If they are both 100 MHz then they sing in harmony. If the memory is 133 MHz (and can not fall back to 100 MHz) then they may give a slightly "off" performance.

That’s because web browsers can display GIF and JPEG images as standard, so web graphics are in those formats. That doesn’t make them in any sense "best".

TIFF is the industry standard format for document scanning, by a very wide margin.
Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format!

These options are not relevant. The PDF file doesn’t include the TIFF information, only the image from the TIFF file.

Are you not saying that it is important to choose the internal image inside the TIFF correctly? I think you are. Then I guess you would concur with Dances-With-Crows about using Group IV. Remember that I do want the option of sending the raw image to colleagues (rather than the shrink-wrapped and sealed PDF).

Thank you for any extra info.
T
tomm42
May 31, 2006
Zak wrote:
"Zak" schreef in bericht
I use XP.

I scan a document to a graphics file (eg jpg, gif, bmp, etc) Then I make a PDF from the graphics file.

I see that if I save a large bitmap (BMP) and then create a PDF then the PDF is no bigger than if I had compressed the image to a GIF and used that to create a PDF file.

In order to preserve quality, avoid artefacts and interference patterns, would it be better to save to a large and detailed intermediate file like a BMP (or even a jpeg) or to save to a small lossless file like a GIF or TIF?

On 26 May 2006, Nils wrote:
Afaik, GIF is not used as a graphical format inside PDF. It is probably compressed as a "TIFF" with Cittfax or LZW compression. "TIFF" is between brackets, because the embedded stream is also not a complete TIFF file, just contains the compressed graphics and some extra information like scansize, colordepth, color channels, etc.

What happens under the hood in your PDF creation really depends on the PDF engine you’re using. Many engines actually resize your graphics to match the PDF DPI resolution. If you’re an experienced programmer you could try to generate the PDF yourself, with the images in full resolution. The PDF specification is open and can be found on the Adobe website.

Nils

Hi Nils and others. I understand now that when I create a PDF from a image file that the format of the image file is not used inside the PDF. Instead some other format is used in the PDF (which Nils kindly suggests may be a specialized form of TIFF).

It is this conversion from my image file format to the internal PDF format which I want to be done smoothly. I am on XP and I am wondering if it is better to start with a GIF or a JPG or BMP or whatever to feed into my PDF creation utility.

I should say that I am starting with a hard copy of a document created on a word processor. I want to avoid artefacts, unecessarily jagged lines, moire effects and all that stuff which might come from transforming from an "awkward2 image format to a PDF.
My PDFs will be for public distribution. I have preferred to scan to a GIF file rather than a TIFF because I have assumed that when I circulate the basic image file among certain people that the best balance between image size and the best chance of them being able to see the file is a GIF.

To me TIFF feels a bit specialized. For example, I never see a web page with TIFF images but I see lots of pages with GIFs.
Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format! The Wikipedia says documents are often scanned to TIFF group 4 but is that something which has the best chance of being seen on various PCs in various organisations that I might need to send it to?

When i creat a document that is going to be a PDF I always use TIF files, mainly because Indesign handles TIF files well. I generally use LZW compression on my TIFs, seems to make no difference. Once the PDF is created the image files, in my understanding are converted to Jpeg files, at least that is how they can be extracted. With the file already being downsampled for the web it is very unlikely you will see jpeg artifacts coming from an orginal TIF. Multiple compressions or resampling from a jpeg is another story. Working from graphics or drawings GIF may be applicable, but for photographs GIFs should be avoided.

Tom
Z
Zak
May 31, 2006
On 30 May 2006, Roger wrote:

However the size of the
original file will have a direct bearing on the size of the pdf.
If you are doing something like creating a newsletter, flyer, or Internet distribution then why not use the original doc file?

Unfortunately, some of the documents have been sent to me in hard copy form.

Also not all pdf creators are created equal. About a year ago I tried using open office to convert a word doc and produced one that was about 3 to 4 times the size of one using Adobe Pro. This is fine for printed media, but may (or may not) be a royal pain in the back side for on-line viewing.

Yes, I feared that once I had mastered the basics then my next task is to identify is my PDF creator is doing as good a job as I might want it to.
Z
Zak
May 31, 2006
On 31 May 2006, tacit wrote:

My PDFs will be for public distribution. I have preferred to scan to a GIF file rather than a TIFF because I have assumed that when I circulate the basic image file among certain people that the best balance between image size and the best chance of them being able to see the file is a GIF.

A GIF is almost the worst possible choice to use, because GIF images contain a very small number of colors, and because of this they don’t tend to downsample smoothly.

DOWNSAMPLE. That’s the word! I ahve just written one if not two paragraphs trying to explain what I man and then you come along and express the idea in a single word!

Use TIFF. Anything that can read a PDF, can read a PDF, period. It does not matter what you start with; once it is turned into a PDF, it is a PDF. However, a TIFF image will downsample and compress smoothly.

To me TIFF feels a bit specialized. For example, I never see a web page with TIFF images but I see lots of pages with GIFs.

That doesn’t mean a GIF is the best format to use for general purposes, however.

OK, so TIFF it is going to be. And to swagger my newly gained knowledge I will add that it might be group 4 or LZW (and I nod very slowly as if I know what I am talking about – which I don’t).

Also there seem to be various compression options for a TIFF (group 3 or 4, LZW, JPEG deflate, none) which might makes it even harder for me to know what to choose as a common format!
Z
Zak
May 31, 2006
On 31 May 2006, Zak wrote:

Then I guess you would
concur with Dances-With-Crows about using Group IV. Remember that I do want the option of sending the raw image to colleagues (rather than the shrink-wrapped and sealed PDF).

Can I add about an additional point to do with TIFFs.

When I go into Acdsee and launch Twain, I am asked what format I want to scan to.

I say TIFF and then I have an option where I can select Group 4. I am also asked to fill in the dpi value horizontally and vertically. I don’t get asked this when I choose to scan to GIF or to JPEG.

When I get into the actual Twain screen I choose the scanning resolution as usual.

So, what values should go into those horizontal and vertical boxes for TIF? Do I need to put in the same value as I use for Twain’s scanning resoultion? (This can be awkward.)

The software is slow to load and if I put in 200 for these TIF value and scan at 266 or 300 then does that lead to problems or loss of quality?

I have tried 200, 300 and 600 in the H & V boxes (at scanning resolutions of 200, 240, 266, 300) and the 200, 300 or 600 seems to make no difference at all to the final size.

I will have to look closely to see the quality.

Can you or annyone else comment on this extra pair of values.
T
Tacit
Jun 1, 2006
In article ,
Zak wrote:

I say TIFF and then I have an option where I can select Group 4. I am also asked to fill in the dpi value horizontally and vertically. I don’t get asked this when I choose to scan to GIF or to JPEG.

Group 4 compression is the compression used by FAX machines. When you send a FAX, the vertical and horizontal resolutions are different; FAX machines use pixels that are not square.

TIFF supports Group 4 primarily to facilitate software that receives FAXes on a computer, or computer programs designed to make scans and then send FAXes. Since that’s not what you’re doing, there’s no reason to use CCITT Group 3 or Group 4 compression (which really only works well on simple bitmaps anyway).


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Dances With Crows
Jun 1, 2006

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On Thu, 01 Jun 2006 12:43:10 GMT, tacit staggered into the Black Sun and said:
In article ,
Zak wrote:
I say TIFF and then I have an option where I can select Group 4. I am also asked to fill in the dpi value horizontally and vertically.
Group 4 compression is the compression used by FAX machines.

Fax machines use Group3, not Group4. Group3 is less efficient than Group4.

send a FAX, the vertical and horizontal resolutions are different; FAX machines use pixels that are not square.

TIFF has supported having different horizontal and vertical resolutions since the format started up; this is not a fax-specific thing. Not many people use this TIFF capability, and some programs will barf if they read different values for TIFFTAG_XRESOLUTION and TIFFTAG_YRESOLUTION, but it’s in the TIFF spec.

then send FAXes. Since that’s not what you’re doing, there’s no reason to use CCITT Group 3 or Group 4 compression (which really only works well on simple bitmaps anyway).

Group4 is A) lossless B) more efficient than any other compression method for bilevel data. These qualities make Group4 an excellent choice for storing black-and-white images. Zak was scanning documents that consisted mostly of text, which is typically very high-contrast and works really well in black-and-white. So every page with just text (no graphics) on it could easily be turned into a Group4 TIFF with no loss of data. HTH,


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