I have an ancient Epsom GT-3500 scanner which still does pretty well everything I want ok. I need a flat bed type for scanning things other than sheets of paper.
However, I only use it with my RISC OS computer via the SCSI port - I can't find any software/drivers that allows it to work with the PC via its parallel port. I *think* it came with a PC SCSI card - but since I didn't have a PC at the time long since gone, as is any PC software for it.
The problem is scanning old car wiring diagrams out of the handbook, etc. If I do this in pure B&W - regardless of resolution and other settings, I get a poor quality image. Scanning in grey gives excellent results - except you can now see the paper 'colour' which often varies according to how it has been exposed to daylight etc in use.
I could transfer the untreated image from the scanner to the PC, and I do have things like Photoshop, but haven't really played with it much.
In GIMP I'd take the greyscale image and use use Colours > Threshold, adjust the slider to pick a good point for the black/white split, then save as some form of B/W image. I'm sure Photoshop has a similar filter.
I'm not totally clear as to whether your problem is with doing the scanning or processing it to black & white.
If you don't have a suitable scanner which works with your RISC m/c, have you considered using a digital camera to photograph the pages of interest, and then importing the photos into the computer?
Is the 'coloured' background reasonably uniform? If so, you can use PaintShop Pro (and probably others) to exchange all instances of one colour (plus or minus a bit) for another colour - so you could convert dark grey to black and light grey/yellowish to white (in two operations).
I get an excellent scan in either grey or colour. It's the B&W which is poor. I don't know if this is because the scanner uses a different 'camera' for this or if it's the software.
With old stuff like this the pages have yellowed and often not uniformly so. And of course the odd fingerprint smudge or so.
What I really need is some 'CSI' software. Feed in a grotty image and it comes out perfect in seconds. ;-)
I'd then be in problems finding a USB driver for RISC OS. I still use that for the majority of things. It's got software I've learned to use and can't be arsed learning new for no real reason.
The Epson was the Rolls Royce scanner of its day and still does most of the things I need well.
The scanner driver setting should allow you to select the gamma, brightness, contrast and the threshold (the cut-off point between white and black). Your photo-editing application should also allow these parameters to be adjusted.
Photoshop certainly does. Try using the "levels" feature which permits you to drag sliders around to set the white level, black level and the midpoint. This will allow you to edit out the grey cast from the white paper. Once you have done that you can use Photoshop to resample the greyscale image into your desired B&W resolution. As a rule of thumb resample B&W to about four times the resolution of the input greyscale image.
However, I'd stick with greyscale, once you have mastered the tricks used for tweaking the output you can get a much better image than you can using B&W - for example on line drawings B&W can look sharper but is more jagged. Greyscale can provide an anti-aliased image in which fine lines and curves are reproduced well on a good colour printer.
You can also get PS to convert greyscale to a clean B&W image. It takes a bit of playing about with and experience but it's fairly easy to do once you have mastered editing the threshold and curves and have played around with the colour mode a few times. I'd make a small test scan of the sort of image and piddle about with that to get a feel for the controls.
There's even an option in the "Levels" dialogue box that lets you take an eyedropper (for say the white level) click on the yellowest part of the page and the page then miraculously becomes white. If the text is then too pale, take the black level eyedropper and click on the darkest part of the text and the text will all change to jet black.
Here you go:
formatting link
the "Save" and "Auto" buttons. When you have a histogram that works for you, you can save it then apply it (Load) to any other scan of a similar type. Auto tries to optimise the image but can also make a complete mess of it. However "Undo" always works if it does foul up.
I posted a similar question to a RISC OS group and got the solution.
It seems the RISC OS TWAIN driver is much more limited than the Epson PC one, so all you basically do is set things for a reasonable image and sort it out afterwards.
The software I'm using does include lots of filters etc but I've never really understood them - since I only really do simple stuff. But the 'Histogram' one allows me to crush the blacks and expand the greys to peak white, giving exactly what I need, and after a quick play look like will be fine.
I know what you mean. I prefer to hold on to good things as well.
About ten years ago I bought a UMAX scanner (Astra 1200S - probably not a rolls royce, but decent enough) for use with my chosen desktop OS, Windows NT4.0. It was supplied with a dodgy DTC ISA SCSI card, but the UMAX driver thankfully also works with an Adaptec 2940UW SCSI card - the mainstay SCSI card of choice for that era.
The UMAX supplied SMPS power unit was a bit finger touch leaky on the output ground connection so I slung that back at UMAX and they sent a replacement which also fried me :-( So I found a cheap uniross linear supply useable until the caps in that died - and am now back to a modern SMPS which doesn't have leakage issues.
So 10 years has developed a better power supply filter(!), but scans from this scanner are as good as others I've seen of a similar equipment spec. It's also seen good scanning use in my succesive operating system upgrades to Windows 2000 and Windows XP - where Microsoft thoughtfully included a WIA driver so I could even ditch the UMAX bundled scanning software and use Microsoft's own scanning wizard.
And then UMAX decided to 'End-Of-Life' (EOL) the scanner, Microsoft dropped the driver support in Windows 7 and this thing was looking for either sole use in Linux or hitting the rubbish pile, like my Matrox Rainbow Runner Studio capture card - never survived the move to XP or my dreams to be alternatively usable in Linux.
"Never give up, Never surrender!"... :-)
I found a useful post[1] on the net on hacking the microsoft WIA drivers preinstalled on Windows XP, into something that would install on Windows
Happilly that works.
Similary my Panasonic Laser Printer KX-P7510 (network version of KX-P7500) was EOL'd by Panasonic before the launch of Windows XP, but the previous Windows 2000 drivers worked there. Now that printer is running fine on Xerox's Global PCL6 Printer driver[2] in Vista and Windows 7, but latterly only when printing from applications installed into Windows 7 (word, excel etc..) but strangly not from built in wizards. Ummm. Windows 7 bug to squash sometime.
And.... I recently recompiled a driver[3] and bought to life an old (10 years old probably as well) 802.11b Cisco wireless laptop network card that originally only had support of WEP encyption, but is now (mainly due to the work of other interested airo-wpa coders) usable in 10.04 LTS with WPA without the kludge of ndiswrapper.
It's a shame that obsolescence is enforced by the non-availabity of drivers, manufacturers sitting on non-interest and NDA rather than open sourcing things that could still have a life. They do want folks to spend more money buying almost identical hardware in some cases.
And don't get me started on the piles of 'dead' freeview set top boxes out there ...
:-(
Links (and model numbers) for the comfort of google'er out there
[1] - Astra 1200S driver for Windows Vista and Windows 7
formatting link
- KX-P7500 / KX-P7510 works with Xerox Global Print Driver
formatting link
- Cisco Aironet 350 with airo-wpa driver and Network Manager
Not unless you trace it to vector after scanning... pure B&W always tends to look a bit harsh and jaggie since you lose any ability to anti alias. Upping the resolution a bit first can help.
Grayscale will give much better results. Note that once tweaked you can usually save as a 4 or 8 colour grayscale gif and get quite decent results without too much file size bulk.
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