by Sergey Samarin
03/07/2005 | 02:59 PM
Each hardware manufacturer has a “top model” among its product nomenclature. The engineers endow this model with best qualities and it comes out proudly with the widest functionality and at the highest price. This review is about one such model – the top-end Scanjet 8200 scanner from Hewlett-Packard. This model isn’t exactly new, but the company hasn’t yet produced a replacement. I will compare this device to the scanners from Epson I have tested in our labs and reported about on our site.
Hewlett-Packard’s scanners line-up, like any serious company’s, is divided into tiers by their functional purpose. HP has four tiers: entry-level scanners, midrange scanners, photosmart scanners (for users interested in photography), and high-performance scanners.
The device I’m going to talk about today – the HP Scanjet 8200 – belongs to the most expensive series of high-performance scanners. The series is comprised of three Scanjet 82xx models and is advertised for small and middle-size businesses.
The HP Scanjet 8200 is the basic model, and the Scanjet 8250 and 8290 are adjusted for high-speed duplex scanning. In this article I will take the high price of this top-model and put it on one cup of the scales and will see if the useful qualities of the device can counterweigh it. For a starter, here’s a table of technical characteristics as declared by the manufacturer.
* Regrettably, Hewlett-Packard never declares the maximum optical density of the original
for its scanners. They may be not very proud about this parameter, or they may
just think this information unnecessary for the end-user.
The package contains:
The HP Scanjet 8200 with the lid open
As I said above, the HP Scanjet 8200 is defined as a high-performance scanner, which fact is specially emphasized. The machine boasts a max optical resolution of 4800dpi and a color depth of 48 bits. Such a high optical resolution helps the Scanjet 8200 to digitize 35mm slides and negatives besides the ordinary stuff like sheet originals and photographs.
The slide-adapter’s lamp is integrated into the scanner’s lid and is powered by connecting its power cable to the appropriate connector on the scanner’s back panel. The fact that HP doesn’t declare the maximum optical density parameter for its scanner again doesn’t surprise me anymore.
The slide-adapter is in the scanner’s cover lid
Before scanning transparent originals you first remove the white screening panel from the lid. Thus you access the slide-adapter unit with a frame for 35mm film and a “slide-feeder”. You can see them in this picture:
Top – the frame for 35mm film; bottom – the slide-feeder
The slide-adapter can be only regarded as an amateurish addition to the scanner; The HP Scanjet 8200 can’t match the Epson Perfection 4870, the competitor top model, in this respect.
Next, the scanner uses a cold-cathode mercury-based lamp, and I find this rather strange on the manufacturer’s part. If they are talking about a really high-performance scanner, they should have equipped it with a xenon-based lamp (with zero warm-up time). This scanner is positioned as an office model, but I doubt office workers will appreciate the necessity to wait even for a minute by the scanner as it’s warming itself up rather than performing the scanning task. The advantage of mercury-based lamps is their low price, so the manufacturer must have just tried to reduce the product cost. That’s why Epson’s GT series scanners look preferable in this aspect.
These connectors are found on the scanner back panel
The scanner connects to the computer via the Hi-Speed USB 2.0 interface. If necessary, you can optionally purchase a SCSI adapter – there’s place left for one inside the Scanjet 8200.
The exterior of the device is official, office-like looking, but for me it looks kind of “old-fashioned” despite its numerous buttons. The case is made of robust gray/silver plastic. The lid is removable (for an easier scanning of thick books). The lid is fixed with two stoppers when lifted to the vertical position.
The scanner offers a wide selection of quick-scan buttons
There are several quick-scan buttons on the scanner’s front panel. Using these buttons you can activate the scanner’s driver with preset digitization parameters. Such an abundance of buttons came as no surprise to me as Hewlett-Packard is known to be into “quick-buttoning”, reassuring the customers that it’s very convenient in practice. My own subjective opinion is that a scanner should have only two buttons, namely Scan and Power. More buttons would suit a multi-functional device better. But again, this is my subjective point of view. By the way, the Scanjet 8200 has no power-off switch, being endowed with power-saving functions. The device turns off automatically after a long time of idleness or you can disable it yourself by pushing the appropriate button.
When working with the scanner I noticed that sometimes it would not wake up from its sleep, and the control program would give out the following error message:
The problem vanishes on a second try: HP’s programmers just didn’t account for the maximum time-out when the scanner starts up with a cold lamp. The program doesn’t get a scanner’s response in time and reacts to it by issuing the error message.
Returning to the buttons, they are programmable. You can assign them different actions though the Buttons Settings utility:
As you see, the window is divided into six tabs. This utility is actually very easy to use, so I won’t describe the process of reprogramming a button in detail.
The exclusive software to the scanner is supplied on one CD. The bundle includes:
The bracketed number is the amount of space on your hard disk drive each of these programs requires. Mark the huge size of the control program. Very large, it is far from perfect in terms of functionality. The program remains unchanged from model to model in spite of the numerous complaints of the users in topical forums. There exists an alternative, of course, but the commercial version of the driver for the Scanjet 8200 from ScannerDrivers (the company that develops drivers for almost every scanner) is going to cost you $100 more. The interface of the control program from HP looks like that:
And here’s the Scan Preferences screen with the basic settings:
I won’t describe the exclusive software from HP in detail since I found no significant changes or innovations there. You can refer to my earlier reviews for more details.
Now that we’ve learned what features the Scanjet 8200 has, we can try and test it.
We will follow our original methodology of testing scanners with the Scanjet 8200, too. But this time there will be one more section concerned with the scanner’s modulation transfer function (MTF). We can do that with the help of an Applied Image QA-69-P-RM test target. So, our tests consist of the following steps:
The computer the scanner was attached to had the following configuration:
The configuration of the testbed remains the same from test to test, so I (and you) can compare the results to those I got in my earlier reviews.
Measuring the scanning speed is like writing an essay on a topic you’re free to choose yourself: the result will largely depend on the writer’s personal tastes and prejudices. Sometimes electronic and paper mass media adjust their test results to suit the potential advertiser. That’s of course unacceptable – they’d better just publish the specification rather than mislead the reader. As for the Scanjet 8200, there are numerous reviews calling it “exemplary fast” and “outstanding”, but it’s not so well in reality. This model isn’t a fresh-new product, so some users have already bought and used it for some time. And I can quote a reader (probably, the head of an IT department) who had bought this outstanding and fast scanner for his office needs, basing on a review from some paper news source:
“After the purchase of a HP Scanjet 8200 we found out that the standard software was so unhandy as to ruin the purchase completely. My users are complaining that this super-fast and super-expensive model works much slower than the older HP Scanjet 5p, and only because the program asks too many stupid questions and warms the lamp up for a whole minute!”
Among the criteria for choosing an office scanner the speed characteristic is foremost, of course. But how is this speed measured? Many manufacturers measure it from the moment the head starts to move and to the moment it returns to the default position. This approach isn’t quite correct with respect to the customer who’s comparing the speed characteristics of scanners by their specifications. Another method – measuring the time it takes to perform a certain scanning task – is more correct and doesn’t put an emphasis on some single step of the scan process. The end-user isn’t interested in how much time the scanner takes to return the head to the initial position. The user is much more concerned about how much time he/she will have to wait for the digitized image to become ready for further processing, as an image in image-processing software or in a file. I’m measuring the speed according to the second method. I even try not to quote the speed characteristics declared by the manufacturer – I’d better measure it myself. I perform this test on a standard 152x102mm photograph, an A4 sheet of paper, and 35mm film (if the scanner comes with a slide-adapter).
So, let’s get to the tests. First I want to inform you that the Scanjet 8200 takes very long, 2 minutes and 45 seconds, to wake up fully from the standby mode. That’s too much, especially for an office machine. And I want to remind you that the scan preferences aren’t saved from the previous session, so you’ll have to spend some time to enter the required parameters.
I didn’t scan the photograph at the scanner’s optical resolution (4800dpi) – the wait wasn’t worth it.
The parameter called resolution is always declared by the manufacturer in the scanner’s technical specification. The real optical resolution is, however, determined not only by the number of the elements of the light-sensitive sensor, but also by the quality of the optical system of the scanner. Good resolution means the scanner’s ability to catch the minutest details in the original. But a scanner with a higher optical resolution doesn’t necessarily produce scans of a higher quality.
We can check this parameter out in practice by digitizing special test targets. Such a target is a set of patterns of white and black lines (“dark-line/white-space” combination). The spatial frequency characteristic of the pattern is determined by the number of pairs of such lines per length unit – line pairs per inch (lppi) in our case. The test target is shown in the next picture:
Applied Image QA-69-P-RM test target
There are five patterns at the top of the target. They differ in their line density: 30, 75, 95, 140 and 180 lppi. I will scan them at the maximum optical resolution of the scanner.
The lines of the pattern are square-wave signals
The high-contrast transitions get blurred in the scan
Besides square-wave patterns there can also be sine-wave patterns in which the lines are originally “blurred”.
The image’s contrast degenerates as the line density increases. We can describe this with the modulation (M) parameter:
Here, Smax and Smin are the max and min levels of the pixels of the image (0 ≤ M ≤ 1).
Having measured the modulation for five areas of the target we can build a diagram that would show the dependence of the image contrast on the line density of the pattern. The results of the Scanjet 8200 are compared to the Epson Perfection 4870:
As you see, the graphs are almost identical, but the Scanjet 8200 is a little worse than its competitor. The similarity of the graphs suggests that the effective resolution of the two scanners is almost the same.
The modulation transfer function, i.e. the frequency characteristic of the optical system, is determined by a similar formula. MTF is often determined with the help of sine-wave patterns. Manufacturers of such targets specify the line density as well as the input modulation parameters. After the digitization and the calculation of the output modulation we can find the value of MTF by the following formula:
If square-wave patterns are used, a reference pattern is first chosen:
The graph above shows the modulation transfer functions for the test patterns. The leftmost pattern of the Applied Image QA-69-P-RM target with a resolution of 30 lppi is chosen as the reference. The modulation functions are determined for the green channel of the target image. The results are presented in the following diagram:
Here you can see the modulation transfer functions for the Scanjet 8200 and the Epson Perfection 4870. Both scanners work at an optical resolution of 4800dpi, so should compare well to each other. As you see, their MTFs is really similar.
When investigating the modulation transfer function I observed a low quality of the scans of the patterns of the target as some colors were prevalent at the borders between the lines. I couldn’t leave this fact unattended and offer you the results of my measurements. First, take a look at a fragment of the scan of the test target digitized in the colorful 24-bit mode at the scanner’s maximum optical resolution.
To evaluate the color aberration I extracted the data and presented them in the following diagram:
This animated picture sequentially shows the green color values (basic for measuring the MTF); red outline to the right of the stripes, blue outline to the left, and the graph shows the color offset value; the Hue diagram shows what colors are prevalent at the borders of the lines. Besides that I noticed correlated noise at some frequencies which shows up in the scan as vertical lines.
Virtually every image produced with digital cameras or scanners has noise constituents. This noise appears due to interference in the useful signal of the light-sensitive sensor. You can’t avoid this, but we can evaluate this parameter by calculating the amount of noise. Noise can be either random or correlated, so we have two test steps in this section. Why calculate the noise? Because the signal-to-noise ratio value will show us how well the scanner’s electronics is protected against interference of all kinds.
Refer to our scanner testing methodology for details about how the measurements are taken. The diagram below shows the dependence of the random noise on the reflection power of the grayscale sectors of the KODAK IT8.7/2 Q-60R2 target.
The signal-to-noise ratio, which is the ratio of the median of a grayscale sector to the deviation, should be regarded as “bigger is better”. That is, the bigger the SNR, the higher the scanner’s noise tolerance is. The delta SNR parameter is the total of the measurements. The next diagram compares the Scanjet 8200 to scanners I’ve tested before:
As you see, the Scanjet 8200 is worse than the modern scanner models from Epson in this test, but by a small margin.
Correlated forms of noise are the most annoying – they show themselves in the scanned image as regular “patterns” (usually horizontal or vertical stripes). The predominance of such noise greatly reduces the signal-to-noise coefficient, which is calculated as the ratio of the median to the deviation. The calculated coefficients are put into the next diagram:
The Scanjet 8200 is worse than any Epson scanner in terms of resistance to correlated noise, as you can clearly see in the diagram. It means that the electronics of the Scanjet 8200 is less tolerant to interference. In some cases correlated noise is discernable in scans made at the maximum optical resolution. Moreover, there are color aberrations which are visible on high-contrast areas of the target (black text on white background, raster lines and others).
This section is concerned with evaluating the deviation in the scanners’ interpretation of the colors of the original IT8.7/2 target with the help of a color management system. In other words, we will learn the coefficient of the color distortion introduced by the scanner into the image, comparing the measured values on each section of the target to the data from the manufacturer of this target.
The gamut range of the scanner in the visible spectrum is identified with a triangle in the diagram. Knowing the coordinates of the vertices of the triangle we can calculate the total area of this triangle. Then we can compare the Scanjet 8200 to earlier-tested scanners.
Judging by the result, the gamut range of the Scanjet 8200 is almost identical to the standard profile sRGB IEC61966-2.1. By the way, the scanner is an input device, so it must have a wider gamut range than a monitor or a printer.
You can assess the quality of the scans by yourself. Below are images digitized with the HP Scanjet 8200:
Hewlett-Packard used to be a leader in the scanner market, updating its product line quite frequently. HP’s scanners featured cute design and good functionality. In those times (not long ago, by the way) the Scanjet brand, and maybe AGFA’s SnapScan, enjoyed the best recognition and highest popularity in the market. But I think HP’s improper price policy at some stage led to the company’s losing its positions here. New players emerged who offered simple but functional models that appealed to the user not only with their low price but also with good software support. According to IDC, the sales of leading companies shrunk so heavily that AGFA had to leave the SOHO scanner market altogether, not coping with the aggressive market competition. Now we see that HP has lost its leadership, too. The model range isn’t as frequently updated as before, and the models themselves can’t stand a critical glance. People buy HP scanners more of “inertia” now – they still trust the renowned brand.
Basing on the results of my today’s tests I wouldn’t recommend spending such a big sum of money for a Scanjet 8200. If you need a really high-performance office machine to digitize sheet originals you may want to consider Epson GT scanners. And if you intend to spend no more than $500 and have a good device with an option of scanning slides and film, Epson’s top-model will suit you best. Hewlett-Packard has long lost its leading role in this market.