From Newsgroup: sci.electronics.design

I have a few hundered feet of bookshelves. I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu). If they are
readable and complete I'll dispose of the physical copy.

But the PDF's in particular are often very slow to nagivate because of
the colouring and texture of thepage background, which can take quite
a while for the PDF program to generate.

I've tried converting the background colour to white, and the scan
postprocess tools available in the likes of Acrobat, but these always
interfere with the text (make it blurry) and mahe the PDF's unpleasant
to read.

Has anyone been through this and found a decent workflow to lighten
PDF backrounds without touching the text?
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On 8/16/2026 11:13 AM, JM wrote:

I have a few hundered feet of bookshelves. I've been going through
the books and downloading scans of them, if I can find them somewhere.

Gee, isn't this fun? (not) I have about 30 ft of shelfspace that
remains to be digitized (before I move on to "paper notes and
receipts") after having processed some 80 "photocopier paper cartoons"
of books. <frown>

Those that remain have to be "unbound" (I have a guillotine cutter
that allows me to chop the bindings off without introducing
the "cutting skew" that a paper cutter introduces) before scanning.

These are mostly in PDF format (or sometimes djvu). If they are
readable and complete I'll dispose of the physical copy.

I only use PDF for those things where presentation is important
as it limits the devices I can use to read the files.

But the PDF's in particular are often very slow to nagivate because of
the colouring and texture of thepage background, which can take quite
a while for the PDF program to generate.

The PDF *render* or the *composer*? I.e., is this a one-time
activity or one that occurs every time you try to read the
document?

For one that you "found online", do you have a URL to demonstrate?

I've tried converting the background colour to white, and the scan postprocess tools available in the likes of Acrobat, but these always interfere with the text (make it blurry) and mahe the PDF's unpleasant
to read.

Are you trying to preserve color? Greyscale? I.e., have you tried
converting color to greyscale; greyscale to monochrome?

Has anyone been through this and found a decent workflow to lighten
PDF backrounds without touching the text?

--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

"JM" <sunaecoNoChoppedPork@gmail.com> wrote in message news:umu38l9552gkf9fgeprn2r9k8el08rmjj4@4ax.com...

I have a few hundered feet of bookshelves. I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu). If they are
readable and complete I'll dispose of the physical copy.

I find it hard to get rid of physical copies but it's probably true that I should get rid of more than I do.
I have some but not many books which can't be found online as pdf or some
other format.
I find it just as easy to lose the pdf file as the physical book. It has to be in
a folder somewhere.

But the PDF's in particular are often very slow to nagivate because of
the colouring and texture of thepage background, which can take quite
a while for the PDF program to generate.

Sounds like this may be because it's having to ocr images.
I've noticed that pdfs vary a lot in quality and size of file.
Bigger isn't necessarily better.

I've tried converting the background colour to white, and the scan postprocess tools available in the likes of Acrobat, but these always interfere with the text (make it blurry) and mahe the PDF's unpleasant
to read.

Has anyone been through this and found a decent workflow to lighten
PDF backrounds without touching the text?

https://www.pdfgear.com/
may or may not help.


--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On 8/16/2026 11:47 AM, Edward Rawde wrote:

"JM" <sunaecoNoChoppedPork@gmail.com> wrote in message news:umu38l9552gkf9fgeprn2r9k8el08rmjj4@4ax.com...

I have a few hundered feet of bookshelves. I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu). If they are
readable and complete I'll dispose of the physical copy.

I find it hard to get rid of physical copies but it's probably true that I should get rid of more than I do.

I used to *cling* to "books" as if they were sacred. No marks, no dog-ears, etc.

But, after a lifetime, you end up with *so* many that they start to make demands on you -- where they are stored, how htey are stored, how they
are organized, etc.

When I got my first Nook, I quickly realized that *all* of my novels
were just taking up space -- instead of putting them on microSD cards
and carrying the whole library with me (sadly, ereaders don't have
an effective way of organizing large collections -- they seem to be
tailored to folks reading the most recent crop of "Best Sellers")

Text books are more difficult as they often have illustrations and
other presentation aspects that are key to understanding the content.
Ditto research papers, data books, etc.

Databooks can often be DLed so that avoids that issue (except for
older items that have particular interest).

Research papers are almost always available in PDFs -- even if they
happen to be in 8.5x11 format.

Text books are the hardest to find, create and review.

I now use an 18" tabletPC for the items that can't easily be
"reflowed" like an epub. It's a bit large/heavy -- but no worse
than a similarly sized textbook.

I have some but not many books which can't be found online as pdf or some other format.
I find it just as easy to lose the pdf file as the physical book. It has to be in
a folder somewhere.

As with every "file" that I have, I have a database that tracks its location (which medium, which folder/container, etc). Along with any duplicates that may be replicated elsewhere (e.g., projects often reference the same datasheets so those naturally appear in each "project folder")

My database lets me annotate each entry with a freeform note (to myself). Sorting based on the *presence* of such a note is often enough to find what
I am interested in as its presence means the item was of sufficient interest for me to have made that annotation.

Or, look at the enclosing folder hierarchy ("Ah, this was part of Project X" and rely on personal memory to augment that structure)

But the PDF's in particular are often very slow to nagivate because of
the colouring and texture of thepage background, which can take quite
a while for the PDF program to generate.

Sounds like this may be because it's having to ocr images.
I've noticed that pdfs vary a lot in quality and size of file.
Bigger isn't necessarily better.

PDFs are just containers. You can put images, text, binaries, multimedia, etc. into a PDF. How it *appears* is up to the person who crafts the PDF.

I've tried converting the background colour to white, and the scan
postprocess tools available in the likes of Acrobat, but these always
interfere with the text (make it blurry) and mahe the PDF's unpleasant
to read.

Has anyone been through this and found a decent workflow to lighten
PDF backrounds without touching the text?

https://www.pdfgear.com/
may or may not help.

There are a lot of online tools to process PDFs. But, that becomes tedious when you have gigabytes of individual files that have to be "uploaded", processed and downloaded. And, you likely need to review each to ensure something hasn't been excised from the original that may have value.
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

"Don Y" <blockedofcourse@foo.invalid> wrote in message news:115t30n$ec5k$1@dont-email.me...

On 8/16/2026 11:47 AM, Edward Rawde wrote:

"JM" <sunaecoNoChoppedPork@gmail.com> wrote in message news:umu38l9552gkf9fgeprn2r9k8el08rmjj4@4ax.com...

I have a few hundered feet of bookshelves. I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu). If they are
readable and complete I'll dispose of the physical copy.

I find it hard to get rid of physical copies but it's probably true that I >> should get rid of more than I do.

I used to *cling* to "books" as if they were sacred. No marks, no dog-ears, etc.

But, after a lifetime, you end up with *so* many that they start to make demands on you -- where they are stored, how htey are stored, how they
are organized, etc.

When I got my first Nook, I quickly realized that *all* of my novels
were just taking up space -- instead of putting them on microSD cards
and carrying the whole library with me (sadly, ereaders don't have
an effective way of organizing large collections -- they seem to be
tailored to folks reading the most recent crop of "Best Sellers")

Text books are more difficult as they often have illustrations and
other presentation aspects that are key to understanding the content.
Ditto research papers, data books, etc.

Databooks can often be DLed so that avoids that issue (except for
older items that have particular interest).

Research papers are almost always available in PDFs -- even if they
happen to be in 8.5x11 format.

Text books are the hardest to find, create and review.

I now use an 18" tabletPC for the items that can't easily be
"reflowed" like an epub. It's a bit large/heavy -- but no worse
than a similarly sized textbook.

I have some but not many books which can't be found online as pdf or some
other format.
I find it just as easy to lose the pdf file as the physical book. It has to be in
a folder somewhere.

As with every "file" that I have, I have a database that tracks its location (which medium, which folder/container, etc). Along with any duplicates that may be replicated elsewhere (e.g., projects often reference the same datasheets
so those naturally appear in each "project folder")

I use databases too, but there's no way I could use a database to track the location
of a book because the database would never be up to date with the book's current location.

My database lets me annotate each entry with a freeform note (to myself). Sorting based on the *presence* of such a note is often enough to find what
I am interested in as its presence means the item was of sufficient interest for me to have made that annotation.

Or, look at the enclosing folder hierarchy ("Ah, this was part of Project X" and rely on personal memory to augment that structure)

But the PDF's in particular are often very slow to nagivate because of
the colouring and texture of thepage background, which can take quite
a while for the PDF program to generate.

Sounds like this may be because it's having to ocr images.
I've noticed that pdfs vary a lot in quality and size of file.
Bigger isn't necessarily better.

PDFs are just containers. You can put images, text, binaries, multimedia, etc.
into a PDF. How it *appears* is up to the person who crafts the PDF.

I've tried converting the background colour to white, and the scan
postprocess tools available in the likes of Acrobat, but these always
interfere with the text (make it blurry) and mahe the PDF's unpleasant
to read.

Has anyone been through this and found a decent workflow to lighten
PDF backrounds without touching the text?

https://www.pdfgear.com/
may or may not help.

There are a lot of online tools to process PDFs. But, that becomes tedious when you have gigabytes of individual files that have
to be "uploaded",
processed and downloaded. And, you likely need to review each to ensure something hasn't been excised from the original that may have value.

--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On 16/08/2026 19:13, JM wrote:

I have a few hundered feet of bookshelves. I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu). If they are
readable and complete I'll dispose of the physical copy.

I trust original paper copies of books to survive.

AI companies are buying up secondhand books at a prodigious rate and destroying them to train AI ready for the singularity. Although what use
"How to pass your driving test in Wales" is to something intending world domination is a mystery to me.

But the PDF's in particular are often very slow to nagivate because of
the colouring and texture of thepage background, which can take quite
a while for the PDF program to generate.

Image to text can work but you need to carefully proofread every page.
many books are already available in online digital libraries.

I've tried converting the background colour to white, and the scan postprocess tools available in the likes of Acrobat, but these always interfere with the text (make it blurry) and mahe the PDF's unpleasant
to read.

The trick is to use a greedy histogram equalisation down to 4 colours
which leaves enough margin to smooth the text and also lose the foxing.
If they are full colour scans then split to RGB first and use only the
red channel (which is usually pristine).

Has anyone been through this and found a decent workflow to lighten
PDF backrounds without touching the text?

Smart histogram equalisation is the only way to do it.
Possibly with a bit of unsharp masking first to sharpen up the edges.
--
Martin Brown

--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On 8/16/2026 12:41 PM, Edward Rawde wrote:

As with every "file" that I have, I have a database that tracks its location >> (which medium, which folder/container, etc). Along with any duplicates that >> may be replicated elsewhere (e.g., projects often reference the same datasheets
so those naturally appear in each "project folder")

I use databases too, but there's no way I could use a database to track the location
of a book because the database would never be up to date with the book's current location.

Physical books tend to "wander" more than files do. I.e., if "here" was a good place for a file, then it is likely *still* a good place.

You can always make a *copy* of it, elsewhere, but no need to eliminate the original (esp if you've established what amounts to a "library" to contain it)

--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On 8/16/2026 12:42 PM, Martin Brown wrote:

On 16/08/2026 19:13, JM wrote:

I have a few hundered feet of bookshelves.-a I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu).-a If they are
readable and complete I'll dispose of the physical copy.

I trust original paper copies of books to survive.

I'm not that confident. I have many paper books that have pages that
have become very brittle. Others where the pages "snapped off" at
the binding edge.

AI companies are buying up secondhand books at a prodigious rate and destroying
them to train AI ready for the singularity. Although what use "How to pass your
driving test in Wales" is to something intending world domination is a mystery
to me.

Just more "patterns of words" to train against.

But the PDF's in particular are often very slow to nagivate because of
the colouring and texture of thepage background, which can take quite
a while for the PDF program to generate.

Image to text can work but you need to carefully proofread every page.
many books are already available in online digital libraries.

You can store the image (monochrome, greyscale, color, etc.) AND the
OCR'd text "on top of it" (invisibly) in a PDF. This increases the
size of the PDF beyond what a "pure" PDF would require. But, is invaluable
if you suspect the OCR process of being faulty.

You can also repeat the OCR with the imagery in the PDF as technology improves. (But, this means you want to scan -- and preserve -- at high enough resolution to enable that "post processing")

I've tried converting the background colour to white, and the scan
postprocess tools available in the likes of Acrobat, but these always
interfere with the text (make it blurry) and mahe the PDF's unpleasant
to read.

The trick is to use a greedy histogram equalisation down to 4 colours which leaves enough margin to smooth the text and also lose the foxing. If they are
full colour scans then split to RGB first and use only the red channel (which
is usually pristine).

Has anyone been through this and found a decent workflow to lighten
PDF backrounds without touching the text?

Smart histogram equalisation is the only way to do it.
Possibly with a bit of unsharp masking first to sharpen up the edges.

--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

Don Y <blockedofcourse@foo.invalid> wrote: |---------------------------------------------------------------------|
|"[. . .] |

I trust original paper copies of books to survive. |

| |
|I'm not that confident. I have many paper books that have pages that|
|have become very brittle. Others where the pages "snapped off" at |
|the binding edge." | |---------------------------------------------------------------------|

Dear Don Y:

Thanks for these data. Do you have any conclusions or hints for
predictions of which books shall have problems? E.g. are acid-free
pages better than acidic pages? Are cheap paperbacks worse than
expensive first runs? (I dislike that novels' first editions are big
(i.e. heavy) whereas if I wait many months I can get comfortable small paperback editions.) Are attics and garages and sheds bad storage
locations? One of our libraries uses a dehumidifer - my own first
dehumidifier is of almost the same model but I do not use it
specifically for papers. Are plastic folder polypockets really
effective at protecting papers? One end thereof is open and humidity
is microscopic.

Old pages can become yellow.
(S. HTTP://Gloucester.Insomnia247.NL/ fuer Kontaktdaten!)
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On 8/16/2026 12:54 PM, Don Y wrote:

On 8/16/2026 12:42 PM, Martin Brown wrote:

On 16/08/2026 19:13, JM wrote:

I have a few hundered feet of bookshelves.-a I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu).-a If they are
readable and complete I'll dispose of the physical copy.

I trust original paper copies of books to survive.

I'm not that confident.-a I have many paper books that have pages that
have become very brittle.-a Others where the pages "snapped off" at
the binding edge.

E.g., this is one of my most precious books:

<https://www.ebay.com/itm/166621567173>

I have taken EXTREMELY good care of it.

But, the pages are of a very heavy weight -- "quality" -- to
support the color plates rendered thereon. The pages are
almost like index cars in terms of weight. It has a sewn
binding (instead of a "perfect binding") and the pages now
"snap" off at those perforations.

I will, eventually, let each page snap off and scan them on
my flatbed (much better resolution and color integrity than
the autofeed scanners). But, I'd like to delay the stress
associated with that event...
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

Martin Brown <'''newspam'''@nonad.co.uk> wrote:

On 16/08/2026 19:13, JM wrote:

I have a few hundered feet of bookshelves. I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu). If they are
readable and complete I'll dispose of the physical copy.

I trust original paper copies of books to survive.

AI companies are buying up secondhand books at a prodigious rate and destroying them to train AI ready for the singularity. Although what use "How to pass your driving test in Wales" is to something intending world domination is a mystery to me.

But the PDF's in particular are often very slow to nagivate because of
the colouring and texture of thepage background, which can take quite
a while for the PDF program to generate.

Image to text can work but you need to carefully proofread every page.
many books are already available in online digital libraries.

I've tried converting the background colour to white, and the scan
postprocess tools available in the likes of Acrobat, but these always
interfere with the text (make it blurry) and mahe the PDF's unpleasant
to read.

The trick is to use a greedy histogram equalisation down to 4 colours
which leaves enough margin to smooth the text and also lose the foxing.
If they are full colour scans then split to RGB first and use only the
red channel (which is usually pristine).

Has anyone been through this and found a decent workflow to lighten
PDF backrounds without touching the text?

Smart histogram equalisation is the only way to do it.
Possibly with a bit of unsharp masking first to sharpen up the edges.

Physical media rocks, for many reasons.

Phil Hobbs
--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On 16/08/2026 20:54, Don Y wrote:

On 8/16/2026 12:42 PM, Martin Brown wrote:

On 16/08/2026 19:13, JM wrote:

I have a few hundered feet of bookshelves.-a I've been going through
the books and downloading scans of them, if I can find them somewhere.

These are mostly in PDF format (or sometimes djvu).-a If they are
readable and complete I'll dispose of the physical copy.

I trust original paper copies of books to survive.

I'm not that confident.-a I have many paper books that have pages that
have become very brittle.-a Others where the pages "snapped off" at
the binding edge.

I guess you have a much bigger variation in humidity than we do.

Even my ancient reference books that are in the attic where temperatures fluctuate a lot are still in pretty good condition half a century later.
The paper yellows and there is some foxing on the oldest books.

A few of which are centuries old (but they are well cared for).

I think I have only ever had one of my own books fall apart on me.

Image to text can work but you need to carefully proofread every page.
many books are already available in online digital libraries.

You can store the image (monochrome, greyscale, color, etc.) AND the
OCR'd text "on top of it" (invisibly) in a PDF.-a This increases the
size of the PDF beyond what a "pure" PDF would require.-a But, is invaluable if you suspect the OCR process of being faulty.

You can also repeat the OCR with the imagery in the PDF as technology improves.
(But, this means you want to scan -- and preserve -- at high enough resolution
to enable that "post processing")

It has come on a long way since the early days when any tables of data
would end up as complete nonsense. These days AI closes the loop so that
you get words of the right type (noun/adjective/verb etc) in the right
places but not always the words that were on the printed page.
--
Martin Brown

--- Synchronet 3.22a-Linux NewsLink 1.2