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In The Lab
From the Mailbag: Scanners, Service Packs, and Hard Drives
by chris

I am looking to start scanning some old negatives, old b&w pics as well as family photos. What is a good quality scanner? I am also looking to go paperless at home so I need a good scanner to do things like save taxes, receipts, bills, legal stuff (we don't pay our bills online). Is there one good scanner or am I better off with two separate items. At this time I don't plan on making my own prints. Thanks for any help, it's very confusing.
- Joanne


Scanners have come a long way over the years. Most photo scanners will be able to scan at a resolution of 4800 DPI (dots per inch) or more, capturing the finest details of your documents or pictures. All-in-one and low-cost document scanners may have a resolution of only 1200 DPI, although with precision stepping of the scan head they may allow resolutions of 4800 DPI down the page. It's a good thing hard drive capacities have increased, because you will need it if you start scanning large pictures, especially in color.

Image Resolution

The resolution of a photo can be calculated the same way the as the area of a rectangle. For example, if you were to scan a typical 4 x 5" photo at 4800 DPI, you get the number of pixels on each side by multiplying the inches by the DPI:

  • Width: 4" x 4800 DPI = 19,200 pixels
  • Height: 5" x 4800 DPI = 24,000 pixels

Then multiply the width and height in pixels to get the resolution:

  • 19,200 pixels x 24,000 pixels = 460,800,000 pixels (or 460 megapixels)

To calculate the size of a raw image file, multiply this number by the color depth (most scanner specifications list 48-bit color; at 8-bits per byte, take your image resolution and multiply by 6). That comes out to something like 2.7 GB per picture if it were to be saved with no compression, like an uncompressed BMP or TIF file format.

What it comes down to is that you don't need to scan anywhere near the maximum resolution of the scanner. The exception is when you scan negatives or slides. If these are 35mm negatives for example, the dimensions of your original are pretty close to 1 x 1.5". If you go through the math, this still comes out to 34.5 million pixels or 200 MB for uncompressed color images. Saving the file in a JPG or other "lossy" format, you might be able to get this down to a "tiny" 20-30 MB file depending on your settings. Most negatives will start to reveal the grain that makes up the image by the time you get anywhere close to the upper resolution of the scanner.

Scanning receipts and other documents will take much less capacity, even at high resolutions, because the color depth may be in shades of grey or just two colors if scanning in black and white. When deciding which mode you scan in, you should consider what you might need to do with the scanned document. If you did have to print a hard copy, what is the printer resolution? Most laser printers are now at either 600 DPI or 1200 DPI, but most documents might be quite acceptable at resolutions of 300 DPI or less. Take the size of the document, whether it is a check, bank statement, or whatever, and go from there. There's not much point to scanning at higher resolutions than you would print with unless you might want to zoom or magnify the result for some reason.

Since you indicate you want to go "paperless" and were not planning on printing the pictures, you can consider what you do want to do with the images. Look at the resolution of the display media you do want to use. If you were to view your pictures on a high definition TV or computer monitor, you would want the scanned image to be at least as good as the screen resolution. HDTV 1080 means the image is 1920 x 1080 pixels. If you were to scan your 4 x 5 photo to come out close to the screen resolution, we can calculate from the long dimension 1920/5 = 384. So if you scan the photo at 384 DPI, the resulting image will be very close to 1:1 - one scanned pixel of the photo = one pixel of your monitor screen. If you scan at a lower resolution, the image either will not fill the screen or will have to be stretched to do so, exaggerating the pixel edges. If it is higher resolution, you will only be able to see part of the image or have to shrink it to fit, "throwing away" data and losing some fine detail. Of course, the advantage of scanning higher resolution than the target media means you have the detail there if you want to "zoom" or magnify a portion of the image to look closer.

To scan 35mm negatives or slides, your scanner must have a "transparency" adapter. This can be a moving light bar that moves at the same speed as the scanner head, or, more commonly, a stationary backlight. If you have transparencies that are larger than 35mm, such as the old 120mm box cameras or even 4 x 5" medium format cameras, then you need a transparency adapter that is larger than the film you want to scan. Most of the time you can narrow your product search by reviewing the specifications or feature list. For example the Epson Perfection 4490 Photo Scanner has a "Slide / Negative Adapter" that supports up to 120 x 220mm film.

If you are just looking at scanners in the store, you will notice that the scanners with the transparency adapters all tend to have thicker than normal lids. If you open the lid, you should see a small window or diffuser where the backlight will shine through your slide or negative. When reviewing scanners online, look for the "Slide and Negative Adapter" feature for capabilities.

Here are some file size comparisons of greyscale and color scans of a 4x5 photo at just 1200 DPI:

File Format Greyscale Color
BMP 25,706 KB 77,921 KB
JPG 17,821 KB 24,743 KB
TIF 25,711 KB 77,927 KB


Since installing Microsoft XP Service Pack 3, something is causing my laptop to not go into Standby mode when I close it. Also, all the icons on my desktop are now larger and the computer will not allow me to change the screen resolution.
- Norma


It sounds like a couple of things happened here. The option to go into Standby is part of the power management options. The icon size and screen resolution are related, and tied to your video display driver. Why Service Pack 3 would have caused the issues, I cannot say. But one possibility could be that one or more files used by the device drivers got changed in the SP3 update, causing the original drivers to "fail" when the feature support got updated.

Icons will appear larger because the screen resolution has been reduced to a size supported by the generic VGA display driver. You may be able to correct this by deleting the device in device manager and having Windows redetect the device, or by downloading the newest driver from the vendor website. If this is a higher-end chipset like NVIDIA or ATI, you may be able to find a generic driver update for your system on the chipset manufacturer website - but you will have to know what chipset your laptop uses to make the correct selection.

Image Resolution

You may have more issues than these, and just not know it yet. The first place to start will be Device Manager. Right Click on "My Computer" and select "Properties." Select the "Hardware" tab and then click the button labeled "Device Manager." First look for any device that has a yellow icon next to it; this usually indicates a failure to initialize that specific device. If you right click on a device with an issue and select "properties," the "General" tab includes a "Device Status" box that may have information about the failure. Equally important will be what device name appears. If your video driver got removed, chances are the listing under "Display Adapters" will only show something like "Generic VGA" or "VGA compatible." The VGA compatible adapter will typically only support very low screen resolutions, making your icons appear to be very large. Icons under XP are usually 32 x 32 pixels, and this won't change, even though your screen resolution might. That's why they seem to get smaller and smaller as the resolution of the desktop is increased. After all, the screen size didn't change, just the number of pixels being displayed.

Assuming your display adapter is now listed as VGA or is the correct video chipset but has problems, one thing you can try is to remove and redetect the hardware. Right click on the offending device in the list and select "Uninstall" or just select it and press the "delete" key. Next, right click on "My Computer" at the very top of the list and select "Scan for hardware changes" to redetect things. If Windows can still find the correct drivers it will install them automatically. If you are connected to the Internet I would let it search for the newest drivers online, since these may be newer than what you had when the problem started.

For the Power Management options, this could be something as simple as a change to one of your advanced settings, or a driver-related problem. Drivers for Power Management are going to be much more difficult to isolate, only because there may be several of them. The choices should be based on the chipset drivers that were installed or updated by Windows. These may be the "ACPI Sleep Button" or other devices listed under the "System devices" section of Device Manager. If no yellow symbols are displayed under the "System devices" section of Device Manager, and the advanced settings have no effect, you can try to find updated chipset drivers for your laptop on the manufacturer's website and reinstall these to see if it helps.

Power Options

To check your advanced power settings, start "Power Options" from the Control Panel. Click on the "Advanced" tab and examine your settings. If it still has all of your normal laptop power options, you should see three options under the "Power buttons" section, including "When I close the lid of my portable computer" and a drop-down box with options to "Stand by," "Hibernate," or "Do nothing." My other choice is "When I press the power button on my computer" my desktop system does not show the lid choice, but has "When I press the sleep button on my computer."

The very last option you have to try to correct things would be to roll-back the system by removing the SP3 update. This is usually done in the System Restore wizard, normally hiding in the "System Tools" folder; Click Start, Programs, Accessories, System Tools, System Restore to start the program.

My motherboard gave up the ghost, and I bought a new Dell 630i XPS with the Vista operating system. I would like to take the hard drive from my old Dimension 8200 and put it in the new machine. Is this ok or will the operating system on the old drive cause a conflict of some kind? Thanks for the assistance.
- Thomas


How easily you can put the old hard drive in the new system depends on a couple of things. The most basic is which drive connectors are available and what type of drive you have in the old system.

If this is a PATA (Parallel ATA or IDE) drive, then you must have a free 40-pin connector on the system board or perhaps an unused secondary one on the optical drive cable. (It also helps if you have an available drive bay within reach of the cable, or you will have to plan on replacing that as well). Each 40-pin IDE connection can support up to two IDE drives, one configured as "master" and the other as a "slave" drive. Unless your drive cable is a special "drive select" version, it won't matter which position the drive is on the cable, only what the jumpers on the drive configure it as.

If the old drive is a SATA (Serial ATA) drive, there are no jumpers to set, just connect the drive with a SATA data cable to an available SATA connector on the system board. If you power supply does not have a free SATA power connector, you will need an adapter to convert the 4-pin "Molex" connector to the "L" shaped SATA power connector.

An easier solution all around might be to obtain an external drive enclosure for the old hard drive. This will convert your drive into a portable external hard drive that can be connected through a USB port anytime you want to access your old data, or to use the drive as a removable backup device. You still need to determine if the old drive is a PATA or SATA connection, and then pick up the appropriate 3.5" drive enclosure.

External Drive Enclosures

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