Scanning, ICC profiling and printing

This extra page gives advice on scanning slides and printing digital files, in particular ICC profiles and their use.

Printing from digital

So you've got your self a digital camera, home computer and a printer. You press print. The colours come out awful. What went wrong?

Firstly, you do not need an expensive photo quality printer to get acceptable results. What you need is photo quality paper. This makes so much difference it's unbelievable. I've found that the quality of the print doesn't vary that much if you use cheap photo paper, its just that the cheap paper is thinner and feels less substantial, the print quality is similar.

That will sort out most people most of the time. If you've got a lot of prints to do, go down the high street, they're much cheaper for large numbers of prints (30+) but mega expensive for just one due to the minimum order value.

If you want critical colour balance then the average high street shop will not be good enough and you'll need either a home set up or use a specialist service. Now the bad news, this is expensive. If correct colour is important then YOU MUST CALIBRATE YOUR MONITOR. Imagine fitting out a kitchen. You measure up for a work top, you go down the shop and give them the measurements, but their tape measure has a different scale on it. Its obvious, the work top won't fit. Colour is exactly the same, if your monitor isn't calibrated then you are wasting your time. Adobe gamma is not good enough. The cheapest way to calibrate your monitor is with a Pantone Spyder and PhotoCal software. This will set you back £180 (2003 prices). As well as calibrating your monitor it will also generate an ICC profile for it. Don't even think about just using factory default settings either - not good enough - if I've said this twice already, I'll say it again, you must calibrate your monitor.

Next you need a photo editing and/or printing program that supports colour management such as Photoshop, Photoshop Elements or Paintshop Pro. The full version of Photoshop is by far the best, unfortunately it costs £600.

I assume you've got a photo quality printer. You will now need an ICC profile for the printer. Unfortunately you need a separate profile for each ink and paper combination. Fortunately you can usually get one of these from the manufacturer for free. Paper and ink manufacturers also provide them for their own inks and papers. You can also down load them from the net for a small fee (~$25) or buy the hardware and software to generate them yourself (~£280). Unless you have the hardware solution in which case you can generate a profile for anything, then you must use the ink and paper combination specified in the ICC profile. In reality, this means you must use manufacturers' inks and papers. Even switching to a similar paper makes a noticeable difference, e.g. Canon Photo Paper Pro and Photo Paper Plus. Although I haven't tried it, I would not expect different inks to those in the ICC profile to work at all well.

Photoshop, whilst good, isn't that easy to use for colour management, in fact it took me a long time to figure it all out. There is more than one way of doing things, this method will work.

Open your picture you want to print. If isn't already in it convert the picture to the working space - you should get a warning come up if this isn't so. Personally I use Adobe RGB as the working space as it's a wider gamut than sRGB, that said, you have to look long and hard at identical pictures in the two colour spaces to see any difference. Now go to view and proof set up. Select custom. The profile should be the ICC profile of your printer, intent should be perceptual. Tick black point compensation. Leave the black ink and white paper boxes unticked. Save this proof set up for future use with a meaningful name. Now go to view and select proof (control Y toggles the colour space views). The monitor will now display the image as it will print. Tweak the colours etc. if needed but do not save the file. Any differences between the normal view and the proof view are due to the fact that monitors display colours by combining red, green and blue light whereas printers combine cyan, magenta, yellow and black inks.

Now go to print with preview. Tick show more options. Select "colour management" rather than "output". Source space should be the working profile (Adobe RGB or sRGB) and print space profile should be your printer ICC profile. Use "perceptual" for intent and tick black point compensation. Now go into the page set up and set up paper size and layout. Select print and then make sure its going to the right printer. Go into the "properties" dialogue box which will take you into the printer driver.

I'm using a Canon i950 printer so these instructions will vary for other printers, but the idea is the same - you don't want the driver to apply any correction at all.

Make sure that the paper size and layout is the same as set in Photoshop. The paper type should be the same as for the ICC profile that you have (you'll have to experiment if you're using different stuff but in theory it shouldn't make much difference to the colours, only the amount of ink it squirts out). Set print quality to high and colour adjustment to manual. On colour adjustment click set. Now set all the sliders to the mid point (no manual corrections) and untick "enable ICM". You may need to adjust the colour sliders manually when printing monochrome images to tweek out slight casts, or better still, set up a Photoshop action to do this.

Now exit the driver and print.

You should get a print that matches the image on screen, however, when comparing them view the print in daylight, not under tungsten or fluorescent lighting. Before you can compare however you must convert the colour profile of your image back into that of the monitor (or revert to the saved version). You will never get an absolutely perfect match as the colour gamuts of monitors and printers are different (i.e. the ranges of colours that monitors can display and printers can print are not the same. For example, there's no way you can print neon colours).

Complicated and expensive isn't it? Unfortunately, if you want "what you see is what you get", this is the road you must take.

Scanning

Despite being a digital convert I've got a large collection of 35 mm slides that I'm gradually scanning in. Despite what's been said about the longevity of CDROMs and digital file formats consider this, some 1990 slides that had been stored in the loft in a slide magazine, (ready to load into a projector), had visibly deteriorated over the past 14 years. Other than the temperature variations in the loft, this is as close to ideal storage conditions as you can get. So, slides don't last forever either, but its easier to copy a digital image than a slide.

I scan my slides on a Minolta Scan Dual Scan slide/film scanner. Until recently I haven't bothered with ICC profiles for the scanner, just scan them in, adjust colours and levels manually and that was it. However, the green-magenta balance was definitely off so I looked at ways of cheaply ICC profiling the scanner. This is the best method I found.

First you need an IT8 target. This is a colour slide with a whole load of different colours and gray scales on it. As well as the IT8 target you also need a file that tells the profiling software where the colours are and what they're supposed to be. As of 2004, the cheapest place to get IT8 targets is Wolf Faust. www.coloraid.de. He doesn't accept credit cards but he does take PayPal. I sent cash through the post, two days later I got an email back confirming the order and another two days later the colour target arrived in the post. You can't fault service like that. I just purchased a Fujichrome IT8 target and that seems to work very well for Kodachrome slides as well (he doesn't do a Kodachrome target). A point to note is that the reference file is sent on a floppy disc in Amiga format. Ask if you want Windows or Mac format. It doesn't matter that much though as you can download the reference files from the site for free anyway. It should also be noted that you can buy printed IT8 targets for flat bed scanners and cameras as well.

An IT8 target

So you've got an IT8 target, now what? The Coloraid site www.coloraid.de also has a link to KWLees IPHOTOICC progaram (free) that can create an ICC profile for you. The documentation for the program is non existent and it isn't intuitive but you can find instructions on the web. I did all this but the problem I found was that Photoshop couldn't read in the profile. If I used the iphotoicc program to convert the image to sRGB then photoshop came up with an error for the colour profile information in the file. I don't know if I was doing something wrong, there's something wrong with Photoshop or iphotoicc has a bug in it (ver 1.1.6), but I couldn't get it to work.

Fortunately there is another solution. Rather than use the supplied Minolta scanning software I used Ed Hamrick's VueScan software. www.hamrick.com. Now this isn't free, you need the professional version which in 2004 cost $80. What it will do for you though is produce a far better quality scan than the Minolta software, and it will generate an ICC profile for you from your scanner and embed it in the scanned file. Ed Hamrick's software gets far more shadow detail out from the slides than Minolta's software. A point to watch is that you must make sure that the colour balance is turned off when you're scanning else the software will try to correct the colour balance - not what you want. Although I haven't tried it, you can calibrate a flat bed scanner and use it to profile your printer. You will of course need an IT8 target for your flat bed scanner.

Home page