A few scanning tips

www.scantips.com



I get the email questions below most frequently.

However, I can NOT handle the most common subjects, of tech support or which scanner to buy.

Hardware questions:

How do I fix my scanner?

First, please don't contact me, I am not tech support for anyone, and you will get a quick "I don't know" answer from me. I simply cannot handle the flood of email those world-wide support questions generate (and I probably don't know). Email to me should to be about scanning or my site or material, but not about scanner support.

Don't overlook your scanner's help files, but problems with your scanner (hardware, installation, troubleshooting, drivers, etc) should be addressed to the support department of your scanner manufacturer. Their job is not to teach you how to use it, but if there is a real problem with the scanner, that's about your only solution short of returning it for refund.

There is a list of most scanner manufacturer's web sites here if you don't have a phone number. Phone is much better than email, the support staff can ask questions to discover what you mean when you say "doesn't work" (support hates those specific words because it gives them absolutely no clue about the problem... WHAT doesnt work? WHAT doesnt it do? WHAT do you expect it to do?). Be prepared to describe better what does infact actually happen.

But first, look for online FAQ information on their web site, try to answer it yourself from the provided information (again, do not overlook your scanner's HELP and readme information). Web site organization and navigation is difficult, but the facts of life today are that there is not much other budget for support available in the profit from a $100 scanner.

You can also post questions to the scanner news groups (comp.periphs.scanners and alt.comp.periphs.scanner) and possibly contact someone that has seen and solved the same problem, or has the same mixture of equipment that you do, etc. Many others including myself do attempt to help there, if we know the answer. The possibility of multiple responses is to your advantage there, as not every answer is always of value.   rec.photo.digital is good too, and see the Links section for a good scanner mailing list, and some software newsgroups at comp.graphics.apps.xxxx.

My scanner is not detected

If it used to work, then try unplugging and reconnecting the AC power cable for USB scanners. No guarantees at all, but it may work. Unplugging and reconnecting the Firewire cable in XP also sometimes works.   Give it a few seconds to be detected.  

Also see the UK Umax USB page for some excellent general USB notes that applies to all brands.

For SCSI scanners, see Device Manager Refresh.

I see lines or stripes in my images?

Vertical and horizontal lines have very different causes.

Vertical lines means in the same direction of the carriage travel, down the page on a flatbed, or down the long dimension in a 35 mm film scanner. Horizontal lines means across the width of the flatbed, or across the narrow dimension in a 35 mm film scanner. Horizontal is parallel with the scanner lamp, and at right angles to direction of motion.

Vertical lines are due to certain CCD cells not responding properly, and that "bad spot" is moved down the page by the carriage motor, making streaks. The problem can be due to dust inside the scanner, on the CCD or mirrors, blocking light from reaching the CCD, and these tend to be dark lines (perhaps dark in only one of the RGB channels) and relatively few in number.

The vertical line problem can be a dirty calibration strip, due to allowing liquid to run under the glass edges. Scanners have a white calibration strip under the cover, just past the top edge of the glass, where the carriage is parked. They self calibrate on the light from that white strip. If this strip becomes dirty or discolored or damaged, the sensor cells in that spot receive the wrong calibration, which makes vertical sreaks down the page. The intensity of bad colors is probably affected by the image data (variable in some degree, probably not a constant). Don't let cleaning liquid seep under the edge of the glass. Put the liquid on the cloth, and then the cloth on the glass.

And the vertical line problem can of course be defective sensor electronics in the scanner, and these lines often appear as red, green or blue lines (stuck on), and sometimes in great numbers or width or patterns. Bad colors are probably a constant, not affected by image data. However, a deposited film on the mirrors can be wide and colorful too. Vertical lines tend to always be at the same place on the width of the scanner bed, being caused by specific CCD cells.

The vertical problem has also been reported as due to installation problems for parallel port models too, but in that case, the scanner never worked better, and the entire area of the scan is likely really terrible.

Horizontal lines are an event in time. Rainbow colored lines might be due to a flickering lamp. Or the scanner has an internal high frequency power supply for the lamp, and it might cause such a problem. A faulty or incorrect or insufficient power cube may be the problem. A long extension cord (AC power) can be a problem, try it plugged directly into the wall. Is the problem everywhere, or random locations, or always in one place in the carriage travel? It could be irregular movement of the carriage due to loose belts or sticky guide rods or other mechanical interference can cause "glitches". You might notice the lamp flickering, or watching the carriage carefully while it moves might show some type of binding. Horizontal lines due to lamp problems are random, showing at whatever location of the carriage at that point in time, but a sticky carriage would probably always be seen at the same location. Effects of an insufficient power cube is probably seen all over the image.

Anyway, you have to think about what you see, there is more there than just "lines". In any event, lines are not caused by your scanning procedure, and calling your scanner's Customer Support service seems a good plan.

Horizontal lines in your printed images are likely due to clogged inkjet nozzles. Your printer probably provides a utility to print a test pattern to check for clogged nozzles. If you cannot see the lines in the image on the video screen, the lines are probably caused by the printer. If you can see the lines in the image on the video screen, it is NOT due to the printer. The same idea with color casts, if the video screen image shows the color cast too, then it's not the printer. But if only the printed result is red, then you're probably out of Cyan ink on the printer.

A replacement lamp?

If you won't be using the scanner any more today, make sure the lamp is not on, for longer life. Most scanners sold in the last couple of years have used Cold Cathode lamps.   The good news is that these have a little longer life expectancy than regular fluorescent lamps, as long as the scanners life, so to speak. Because, the bad news is that Cold Cathode lamps are NOT user replaceable. Replacing a cold cathode lamp means that you must ship the scanner back for service. In many cases, buying a new scanner will be less expensive, so you might consider it expendable. The scanner company's Customer Service Dept can at least tell you the situation about lamp replacement. You can recognize a Cold Cathode lamp if it is very thin, perhaps 1/8 inch (3 mm) diameter.

Older scanners used replaceable lamps, typically larger 1/2 inch (12 mm) diameter lamps. These are special lamps having high CRI ( Color Rendering Index). CRI is a measure of color purity, and CRI of 70 to 85 is good for scanners. The scanner company's Customer Service Dept probably sells replacement lamps, at least they used to when these scanners were sold. I'd suggest you should phone them first. Otherwise, these high CRI lamps are difficult to find, it will probably have to be a specialty lamp shop (perhaps try here or here).

One other complication - An apparent lamp failure is sometimes instead a failed lamp power supply and not necessarily the bulb. If you measure the voltage at the lamp, be very careful. The lamp voltage is very dangerous, both high frequency and high voltage, nothing like normal electronic circuit voltages. Unplug the scanner power before you mess with the lamp. "He thought he knew what he was doing" is NOT a satisfying tombstone epitaph.. <grin>

Can I use a scanner over a network?

Generally no, not with desktop scanners. It is not a very practical idea. Two users cannot use the scanner at the same time, not in the way disks are shared, or even how printers queue jobs. Users still must walk back and forth to the scanner to load and unload every scan. The traffic is distracting to the owner of the PC, and the act of scanning loads their PC, they will notice that load too. The owner of that PC might as well go take a break, and they will quickly tire of it. The lost time will soon pay for additional scanners. For example, you likely share a printer, but you don't put the printer at anyone's desk.

The high end HP scanners (6000, 7000 series models) do include networking software to make it possible to scan remotely, but be sure that LAN software is mentioned in the spec for the unit, otherwise it wont be there. Umax scanners used to include similar software, but they don't seem to mention it, I don't know if that is still true or not. The others don't, as far as I know.

Scanners are so inexpensive now, more than one is feasible. Or providing a dedicated PC (without an owner-user) for the scanner is feasible, allowing one to go to the scanner, use the PC there to do the scanning, sharing the image disk files via the network. Cost of that PC vs a few cheap scanners?

Just an opinion, but it doesn't seem a practical idea. I think the scanner user should plan on using the PC where the scanner is installed.

Can I use ScanWizard or MagicScan with my brand XYZ scanner?

No, I would seriously doubt it. Twain drivers are a hardware interface designed to run the specific brand of scanner, and provided by the manufacturer.

Possible exceptions are that VueScan or SilverFast work with many scanners, see their list of supported scanners.


Copyright © 1997-2010 by Wayne Fulton - All rights are reserved.


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