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Profiling your scanner with the Eye One

  |   Articles and reviews, Colour management, Review, Scanner, Software review, X-Rite   |   No comment

Profiling your scanner with the Eye One

i1Match software to profile scanners with the Eye One Spectrophotometer



The Eye One spectrophotometer from GretagMacbeth is a sophisticated measuring device that can measure detailed spectral information from emissive sources (ambient light or a CRT/LCD display) or reflective sources (print samples or just about any coloured object).

By measuring printed targets, it can be used to profile scanners.

eye-one spectro

Scanner Profiling

This review covers the scanner profiling capabilities that you can activate in the Eye One Match software (you can purchase an activation code).

This feature is not active in the Eye One Design package that Keith reviews elsewhere.

That review covers monitor calibration with the Eye One spectrophotometer, basic printer profiling and measurement of ambient light with the Eye One Share package.

There is a separate review of the Camera Profiling option in the Eye One Photo SG package.

spectrophotometer from Gretag MacbethGretagMacbeth provide a range of colour management hardware and software aimed at professional users.

Details of the full range of Eye One solutions are available on the main GretagMacbeth site. [Now X-rite]

Profiling your scanner

If you are completely new to colour management I’d suggest you might also like to have a look over my Introduction to colour management article on this site. However, I have added links, in this review, to articles and information on this site and others explaining some of the concepts mentioned here.

There are two basic types of scanner. One measures reflected light from an object (typically a flat print or document) and the other measures transmitted light (typically film or slides). I’ll be covering profiling two flat bed scanners later, so I’ll concentrate on scanning pictures.

To get an accurate scan, both the characteristics of the light source and the sensor that is being used to capture it need to be considered.

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I often get asked for suggestions about learning more about the nuts and bolts of Colour Management.

My usual suggestion is Bruce Fraser's Real World Colour Management. My own copy is well thumbed. It's my first port of call if I'm asked a question and I feel I don't quite understand an issue well enough to be absolutely sure of an answer.

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See some other books Keith has on the shelf, on our Books Page

Think first of the light source, ideally it should provide illumination that provides a similar range of colours to the light that you would view the subject.

Think of using something like a yellow street lamp bulb and you will see why not all light sources are useful. There are some examples in the Eye One review.

Secondly, there is the sensor that is recording the reflected light. Our eyes capture colour information by being sensitive to three main colours of light (Red, Green and Blue).

It’s actually quite a bit more complex than just three colours, and characterising our colour vision is a specialised field (Spectral response of the eye ) Various optical sensors will have their own characteristics, which may be tailored with the addition of coloured filters.

If you add in the need to have an economical and long lasting light source, and a high resolution sensor to designing a scanner, then you arrive at a number of different basic designs (image scanning – WP)

The upshot of all this is that despite the best efforts of the scanner manufacturers, the representation of colours and brightness (luminance) of your scanned picture may not relate very well to what the picture looks like to you.

One way of addressing this problem is by ‘profiling’ the scanner. You take a known picture, scan it, and compare what the scanner gives you to what you should get. The resulting profile is in effect a ‘translation’ document for use to convert from ‘what is recorded’ to ‘what it should be’

The whole question of input device profiling can become a tricky one when you consider that any colour will produce some sort of output from the scanner, so the concept of a scanner ‘gamut’ is not a meaningful one in the same way as a printer gamut, which is limited by the inks and paper to a certain range of colours. If you think this makes it tricky for profiling scanners, at least they have a constant light source — unlike your camera. I’ll be covering some aspects of camera profiling in a future article.

The scanner driver software, whether a Photoshop plug-in or a full stand alone application may well have numerous correction and adjustment features which you should be aware of, since any profile you build is only relevant to particular scanning conditions.

If you can find a manufacturers profile for your scanner, then do try it, they can make quite a difference, but without profiling the scanner yourself, how can you know whether it’s accurate, or just ‘looks good’?

Profiling

An 8″x11″ printed target is supplied by GretagMacbeth for profiling reflective scanners. This is a patchwork of 288 colours which cover a range of colours at different brightnesses. The Eye One Match software makes use of a ‘Target file’ which contains spectral information on each coloured patch. Note that this is much more than simple RGB values, it gives the brightness of each patch in 10nm bands across the whole visible spectrum. This allows the profile generation software to allow for different types of lighting and sensors.

select scanner profiling

The scanner calibration option is selected in Eye One Match (in this case reflective)

If you have not done so before, you will need to create a target file by scanning the test target with your Eye One spectrophotometer. If you are using another target (such as an IT8 film target), then you select it here.

create a reference chart file

First you need to calibrate the unit with the white patch in the base.

base and calibration target

Sensor and calibration target

Once you have created the target file, it will be available for profile generation without going through this step.

As with all colour management reference tools, you should keep the target print in it’s envelope in a safe place away from light and damp or any other environmental factors that may affect the print (ozone from older laser printers is particularly good at fading prints)

You might be wondering why a target file is not provided and you have to do this step at all. There will be variability in batches of printed targets, and your own Eye One will have its own characteristics, add this to changes over time, and you can see why it is best to create your own target file – producing individual ones for each Eye One sent out would also add considerably to the cost!

Now you have a target file we can see how your scanner’s version of the target differs from what the Eye one ‘saw’. You need to get a scan of the target with your scanner and save it as a tiff file. This is loaded into Eye One Match.

select the scanner tiff file

Notice I’ve got two tiff files from two scanners to select from

You need to rotate and crop the scanned image to get just the coloured patches.

rotate and crop test image

First rotate (CCW in this case)

crop - detail

Then crop to select only the patches

There is one final check to see that the measured chart and the scanned chart are the same one. You can see from the picture that the scanned chart is darker, but it is the same chart (and the right way up)

check that the scan file is correct

Comparing measured and scanned charts

The profile is then created and saved (do remember to give it a meaningful name)

save your profile with a meaningful name

The profile for my UMAX PLIII scanner is saved

Remember that just like monitors, scanner profiles will change over time as the lamp ages, it also helps to have the scanner switched on for a while before profiling, so that everything gets to warm up properly.

How well do the profiles work?

If you want to profile a transmissive (film) scanner then you will need to get a special target. My own Canon FS4000 is used rarely these days since I moved to a fully digital workflow, and when it is used, is mainly for black and white. So I decided to test two flatbed scanners I have in the office:

  • A UMAX PowerLook III – this has a transparency adapter, SCSI interface and is attached to an old Mac running OS8.6
    [2015 still used with a firewire to SCSI converter and Vuescan software under OS X 10.10]
  • An Epson Perfection 1200U – USB flatbed connected to G5 Powermac – OSX
    [2015 still going strong and working under OS X 10.10]

The UMAX may be [very] old, but it is still a very useful scanner :-)

I created two scans (with all corrections turned off in the scanner software) and went through the profile generating process above. Do remember to make a note of all the scanner settings for when you want to use the profiles for real work, since the profile is dependant on the settings being the same.

The picture below shows the original scan from the Epson 1200U.

If you move your mouse over the image you will see the scanned image after opening a raw scan tiff file in Photoshop and assigning the appropriate scanner profile.

The scans from the two scanners look very similar, and once a profile is used, almost identical.

Test pattern from GretagMacbeth Eye-One Scan Target 1.4, Part No 35.56.81

You should be aware that if you take an untagged (i.e. no embedded icc profile) scan and open it up in Photoshop, it will look different dependant on how you colour manage it. You should assign it the scanner profile and then convert it to your working profile if need be. There are some examples of how this affects web images in the article on web colour management.

Just in case you were wondering how big a range of colours the scanner has captured to make the profiles, I used the Mac OS X ColorSync Utility to compare some colour spaces…

epson 1200 space compared to sRGB

The Epson 1200U scanner colour space (grey outline shape) compared with the sRGB space.Apart from a small area near the base, the sRGB space is entirely within the scanner space.

The coloured line represents pure spectral colours

epson 1200 space compared to Adobe98

Same comparison, but this time with the larger Adobe98 colour space. Notice that the overlap is complex, i.e. there are some colours in A98 that couldn’t be captured, and some in the scanner space that can’t be represented in A98.Of course the scanner will give an output for any colour, so it’s not technically correct to describe the ‘gamut’ of an input device. Think of it more as the range of colours that are accurately mapped – outside of the space they may be correct, but they may not be

epson 1200 space compared to a printer space

This comparison is with the Epson 1290 printer using Premium Glossy Photo Paper.Even though the print space is much smaller than the scanner space, there are still a few colours that can be printed but not necessarily accurately captured.

The 1290 with PGP paper produces very good quality prints. I have one myself that produces better glossy prints than my RIP driven Epson 9600. However print lifetime with the glossy dye inks is nowhere near what you could get from the Ultrachrome pigment inks.

2013 – I1Profiler V1.4 now includes scanner profiling

June 2012 – X-Rite are shipping updated i1Pro 2 with i1Profiler 1.3
Reviews: i1Pro 2 Basic – i1Pro 2 Photo

April 2010 X-Rite ship V1.0 of i1 Profiler – Full i1 Profiler reviews and information

May 2010 X-Rite annouce new profiling software for Q4 2010 – i1 Match and ProfileMaker Pro will be superseded by i1Profiler later in 2010. We have some notes and press info in the X-rite information section of the Northlight blog. For purchases after April 1st 2010 here will be free upgrades, along with other offers when the software is available.

Sept. 2008 X-Rite and the i1 range 

From Sept. the range is simplified to two options. The functionality is the same as we have reviewed, but exactly what you get varies. As a result of this rationalisation, the i1Photo, i1Photo SG, i1Proof and i1XT have all been discontinued, and the i1 range now consists of:

  • The i1Basic – i1Pro measuring device with monitor profiling software
  • The new i1XTreme – professional monitor, RGB and CMYK printer, camera, scanner and projector profiling, plus profile editing

With the i1XTreme you can calibrate and profile:

  • Monitors – LCD, CRT and laptops
  • RGB output devices
  • CMYK output devices
  • Scanners
  • Digital projectors
  • Digital cameras*

*Requires Digital ColorChecker SG Chart – available separately.

Summary

Simple and elegant solution to getting accurate scans from your scanner.

The software is easy to use and the required steps are clearly set out.

You probably won’t profile your scanners very often but the way the software steps you through the process makes it much more likely you will remember how it works.

The final quality of the scan is limited by the quality of the scanner, but a profile will help you get the best out of it.

Eye One packages are available from a wide variety of suppliers. It is available for Macs and Windows PCs.

More colour management and printing related information

For information about printers, paper reviews and profiling (colour management) see the Printing section of the main printers and printing page, or use the search box at the top of any page.
All colour management articles and reviews are indexed on the main Colour Management page - please do let Keith know if you've any questions, either via the comments or just email us?

Some specific articles that may be of interest:  

  • Why don't my prints match my screen? A short article showing why there is more to getting your prints to match your screen, than just calibrating your monitor. It's the vital first step, but you do need to consider some other factors for best results.
  • Why are my prints too dark - some basic suggestions to this common problem.

 


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