you've almost certainly heard of six-color printing, with the extra ink colors making it easier to print at true photo quality. but i'll bet you haven't heard about six-color scanning . that's because the scanners you're used to all use three colors for scans.

Six-color scanning yields excellent color quality; Scans photographic prints and film; Can scan up to 16 slides at once

Scan software is cumbersome in some ways and sometimes slow to react to a command

The HP Scanjet G4050 is a solid dual-lamp scanner that could use a driver overhaul and a better means of handling slides.

Excellent scans; especially of very saturated originals; Very nice industrial design

Only supports sRGB colour space; Random colour registration problems on slide scans; Weak driver; Many operations are very slow

Home scanners have shown little technical innovation over the past few years. However, HP's Scanjet G4050 has broken the mould with the first so-called six-colour scanner, using two lamps to provide RGB feedback plus extra colour information.

You may be wondering why HP's Scanjet G4050 costs almost £200, especially as there's not a lot of technical difference between it and the G3010. The key difference is that it supports six-colour, 96-bit scanning. This involves scanning each item twice with two different light sources.

The theory is that the usual source of white light used for scanning doesn't offer full-spectrum illumination, so a separate pass with a separate light source and some extra sensors can fill in the gaps and produce a more accurate result.

Pros: Good colour quality; reasonable build quality; decent support at the price for a wide range of different slide formats

Cons: Can be slow at higher resolutions; slight softening on both paper and slide scans; drivers and software need to be streamlined and simplified

Hot on the heels of the Epson Perfection V700 and V750, which lured customers with the promise of not one but two lenses (reviewed by PC Advisor 's sister website Digit here and here ), comes this ambitious six-colour scanner from HP.

According to HP, the main problem with conventional scanners is that the white light leaves significant gaps in the colour gamut, creating significant colour distortions. The company's solution is to add a new light source that fills the gaps.

Better colour accuracy; Reasonable looks; Good range of supported slides

Dodgy drivers; Very slightly soft focus; Can be slow

I bought myself this to scan various things (old photos, documents and some sheet music ) and this does the job pretty well. It was a bit on the expensive side but I needed something that would give me good quality and I could trust that it would work well so I went for HP as they are well known for...

good quality scanning

software is rubbish; can take for ever to scan an image

HP's G4050 flatbed scanner employs a novel two-pass technique to extract maximum detail.

Build quality; fundamental scan quality is good

Speed; poor control software; large design

I bought a G4050 and tested it on an iMac using Mac OS X version 10.4.11, and a PC using Windows XP (SP2). On both systems, photo scratches on a scanned 4x6 photo that were barely discernable were very accentuated as light noise in the digital images.

Durable

Bad Value; Low Quality; Poor photo scans