The magazine of the Melbourne PC User Group
Hewlett-Packard’s New 4400 Series 
Scanners  
 Major Keary
 
Hewlett-Packard recently released two models in this series, the 4400c and 4470c. The difference is that the 4470c model comes with a transparency adapter. When a scanner captures an image of a picture, page of text, or the like, the data is collected by way of reflected light. Transparencies and negatives are seen by transmitted light, which requires the subject to be placed between a light source and the scanner's sensors.

High quality transparency scanning calls for a dedicated machine, but such equipment is expensive and cannot be used for anything else. My requirement is for a scanner capable of capturing transparencies and negatives in sufficient detail to be used as drop-in images in proposed layouts, to assess the repair/enhancement potential of old film, to provide images for Web publication, and create an archive. The 4470c suits that purpose very well (models below the 4400 series do not have a transparency scanning option).



Figure 1. The HP4400C scanner.

Most of my scanning is of non-transparency images for publication, and OCR conversion. A special requirement is faithful reproduction of very old documents and books, and occasional solid objects (which calls for depth of field). Images for high quality colour printing are sometimes required to be scanned at 1200 dpi; even though that is not frequently called for, the capability is needed.

On the subject of scanning books, anyone intending to use a scanner frequently for that purpose should look for a unit with a narrow side 'margin' between the glass bed and outside edge of the unit. The physical location of the scanner should also be planned. Scanning books requires dedicated desk space, a machine that can support the weight, and a lid that accommodates the thickness of a book.

HP's 4470c fits my purposes, and purse. It sits nicely in the scanjet product range, just below the - more expensive - machines that suit heavy use or the need for high resolution images. In an office where a lot OCR work is done an automatic sheet feeder is an important feature, but is not available on the 4400 series. The 4400 models automatically choose optimum settings for any given scan, which makes them ideal for users who don't want to involve themselves in the technical side of scanning. Handy pop-up text boxes offer advice for the novice. For those who want to control all aspects of a scan that feature does not intrude to any significant degree.

For users who like easy solutions, convenient front panel control buttons make the 4400 machines suitable for use in a small office environment. One button makes the scanner a virtual photocopier; it can be set for up to 99 copies and the scanner sends them directly to the printer. There is also a handy scan-to-CD feature - if you have a CD writer installed. Web and e-mail connectivity is also a button-controlled feature.

A useful option is the save black-and-white images in scalable format, which gets over the problem of jaggies in bitmap images. As with OCR, the user is locked into 100% image size and 300 dpi. The saved file format is WMF, which imports to MS Word and most DTP applications. Moire patterns can be removed with a descreen option.

CCD and CIS

All HP scanners use charge couple device (CCD) sensors as against contact image sensor (CIS) technology. There is significant advantage in CCD, especially depth of field. CIS is cheap and suitable for fax machines, but it provides no depth of field and is usually accompanied by optics that are inferior to CCD systems.

The 4400 series has two separate sensor arrays, one for scans up to 300 dpi and the other for scans between 300 dpi and 1200 dpi. As the diagram shows, sensors in the 1200 dpi array are in two staggered rows. There are a number of technical advantages, but the one that most immediately affects users is faster scanning time in 300 dpi mode.

OCR

The Precisionscan Pro software that comes with the 4400 series machines has integrated OCR capability, which works well for general purposes but can't be trained. Not surprisingly, it doesn't do very well with 3-point type, but handles 5-point with reasonable accuracy. 

Once 'editable text' is chosen for output, the software locks the user into 100% image size and 300 dpi resolution. That has the effect of limiting the character size that can be transformed with OCR. There's not much call for scanning 3-point type, but if you want to do that it is necessary to use dedicated OCR software.

Testing a Scanner

There's more to testing a scanner than capturing and printing a coloured photograph. There is not room to go into the technicalities here, but there are target images designed for the purpose and which cost about US$140.

Colour is a far from clear-cut issue. We see the results of a scan on output devices (monitor, printer, etc.) that each have their own peculiarities in the reproduction of colour. If the output device is properly calibrated it is possible to test results by using a target image with colours of known values.

Resolution is a loosley-used term expressed as dpi, ppi (pixels per inch), or spi (samples per inch). There is more to resolution than the number of sensors. If the carriage that moves, the sensor array wobbles or fails to move at its specified rate and resolution is adversely affected. If the optics are inferior (poor quality lens, imperfect mirrors, shaky mountings), resolution is degraded. A suitable target image is the best tool for assessing resolution.

Noise also affects image quality, often introducing artefacts. One reason for dedicated target images being so expensive is the requirement for a high degree of quality control, which is necessary for detection of noise artifacts and objective measurement of resolution and colour fidelity.

My tests of the HP 4470c indicate that resolution is true to label, and noise levels are minimal. Colour will take time to assess thoroughly, but my subjective judgement is that the scanner performs exceptionally well for its price. I am impressed by its ability to handle greyscale tones, which is a good indicator of overall performance.

If you want to test a scanner for detail and depth of field, use a banana. It may sound odd, but it is a surprisingly effective 'test target'.


Figure 2. A scanned image of a 
banana that shows up a scanner's 
ability to capture detail and depth 
of field.


Figure 3. A negative on black and 
white film, taken some fifty years ago, shows the HP4400C's capability to 
capture greyscale tones and detail 
from a negative.

Software

The software that comes with the 4400 series is HP's Precisionscan Pro, which provides a degree of control that will satisfy power users, as well as offering a friendly interface for the less experienced. The 'advanced' drop-down menu is not for novices; it contains gamma correction, exposure adjustment, colour correction, and bit-depth adjustment, facilities that will please those who know how to use them.

The interface design incorporates scan-to-CD, share-to-web, send-as-email, scan direct to MS Word, and save as PDF.

A third-party OCR application is seamlessly integrated. As already mentioned, it has limitations but for general purposes works well and is very convenient to use.

An image editing application, Photoimpression from ArcSoft, is included. It is a user-friendly package with a slick interface and should satisfy the needs of ordinary users. Those experienced in graphics applications will probably want something more powerful.

Installation

The 4400 series has both USB (cable provided) and parallel connections. If the operating system is USB compliant it is the recommended method of connection. I found no plug-and pray problems with it at all, either in respect of installation or ongoing use.

For users who opt for a parallel port connection the unit has input and output plugs that enable a pass-through printer connection. A special cable - available as an optional extra - is necessary.

Details

The 4400 scanners measure 505 mm x 305 mm and 75 mm high, and weigh in at 3 kg; even though light in weight, the construction is robust - but not designed to be stood upon or to support heavy books, boxes, or whatever. The scanning surface is offset to provide a 25 mm margin on one side (useful when scanning books); and the preview speed is 13 seconds. Scanning speeds vary according to the size and nature of the material and the task; a full A4 page of text takes just over a minute to scan and process for OCR, average-size full colour scans take about 40 seconds.

Operating systems supported include Win9x, Win2000, WinME, WinNT4, and WinXP (but check HP's Web site for latest information on use with XP). The series is also Mac compatible.

The Bottom Line

The 4470c model, with transparency adapter, is - in my opinion - worth the extra cost for users with an ongoing, but moderate, need for working with 35 mm film. The adapter accepts a strip of four 35 mm transparencies and has its own light source; the assembly fits neatly on the scanner bed and is easy to fit and remove.

The RRP of the 4400c model is $299, and the 4470c (with transparency adapter) is $399. Well worth considering for SOHO and personal use. A well-designed unit that incorporates ease of use, functionality, and state of the art technology.

  Reprinted from the March 2002 issue of PC Update, the magazine of Melbourne PC User Group, Australia