Isn't it frustrating when what you get on paper doesn't match what you see on screen? Photo printing can seem like a dark art sometimes, even when you're using some of the latest and greatest printers, like the Canon imagePROGRAF PRO-300 and Canon PIXMA PRO-200.

To some extent, of course, an image will never look exactly the same on paper as on screen, because a print is reflective with subtractive colours (meaning that the more ink you add, the darker and generally muddier colours become) while a computer screen is a transmissive light source itself, with additive colours (the more you add, the brighter and generally more intense colours become). However, there are some initial steps you can take to prevent common problems and minimise surprises, such as calibrating your monitor and adopting a colour-managed workflow. In addition, by careful use of ICC profiles, you can get the best possible match between your image on-screen and in print, helping you avoid disappointment and frustration and put a stop to wasting time and money.

Here Keith Cooper, owner of Northlight Images and renowned industry expert on all things print-related, answers your questions on how and why to use ICC profiles to ensure accuracy and optimum quality in your photo printing.

The International Color Consortium has defined an industry standard for colour management and colour matching across a range of different devices. "An ICC profile works as a translation between different sets of colour capabilities," explains Keith. "Any digital photograph has its own range of colours, represented by numerical data. That range of colours may exceed what your monitor can display, and will almost certainly exceed what your printer can output onto paper. An even bigger factor is that your monitor can display a different range of colours from that which the printer and paper can manage. ICC profiles act as a translation between the source set of colours in the digital image and the destination on screen or in print, the latter using different profiles for specific printers, inks and papers. It takes you from what you've got, to what you want."

"It's not just about glossy paper having more dynamic range," Keith says. "That glossiness also affects the way colours are reproduced, typically with a wider gamut, even when using the same inks. For example, a glossy paper will generally give you really vivid reds and blues, making use of the glossiness of the bright white underlying paper. With a matte paper, the gamut tends to be more muted. For colour prints, matte papers therefore work better for scenes with more subtle colours and less contrast. In any event, the specific ICC profile for the printer, inks and paper that you're using will translate the source digital image to best suit the characteristics of the printing process."

Before you begin, if you're using third-party papers, you might have to download the appropriate ICC profile from the paper manufacturer's website. There are very clear instructions and useful advice about this on the Hahnemühle website, for example.

For greatest control when printing using Canon printers, Canon recommends its own Professional Print & Layout (PPL) software. This is updated from time to time to support new models and features, so it's a good idea to check you have the latest version and, if not, download and install it first. You can use PPL on its own or as a plug-in within your preferred image editing software:

? Canon Digital Photo Professional (DPP): File > Plug-in printing > Print with Professional Print & Layout

? Adobe? Lightroom?: File > Plug-in Extras > Canon Professional Print & Layout

? Adobe? Photoshop?: File > Automate > Canon Professional Print & Layout

? Adobe? Photoshop Elements?: File > Automation Tools > Canon Professional Print & Layout

When PPL opens, select Print, then in the General Settings tab select your printer, Media Type, paper size, quality setting and other options. PPL has a built-in library of ICC profiles for Canon papers and will automatically load the profile to match the Canon paper you've selected under Media Type. If you're using third-party paper, go to PPL's Color Management tab and, under Color Mode, select Use ICC Profile, then select the appropriate profile in the Printer Profile pop-up. ICC profiles you've installed will be available in the list to choose from. If they haven't appeared, did you have PPL or your image editor open before installing? Try relaunching it.

Remember that a profile always refers to a specific printer using specific media – make sure you set both correctly or the results might not be what you expect.

The Media Configuration Tool may be installed when you initially install your printer driver software. Otherwise, visit Canon's printer support page, select your printer, then click Software. Find Media Configuration Tool in the list, and install following the instructions. Your printer User Guide will contain a section explaining how to use the software.

This can be a problem area, Keith admits. "Each device is governed by its own ICC profile but, ultimately, there are colours that can be displayed but not printed, and colours that can be printed but not displayed. If you think of the shape of each profile as a three-dimensional object, the shape of the screen profile and printer profile will be different. When you try to merge the two shapes together, you'll end up with bits sticking out, which represent a mismatch between colours that can be viewed on screen or printed on paper. Even if you buy a really expensive wide-gamut monitor, there are still colours that it won't be able to display, and there will certainly be colours you can see on screen that you won't be able to print on paper."

According to Keith, colour management isn't about getting perfect colour. "It's more about automatically helping you along the process from what you've got to what you want, in the path from digital image file to screen, and ultimately to the printed picture. If you open an image in Adobe Photoshop or PPL, for example, there's a soft-proofing option that aims to show you what an image will look like when using a certain printer and paper, based on its ICC profile. However, because the monitor and printer are only able to reproduce different ranges of colour, the simulation will only ever be an approximation – although if you're using a colour-managed workflow, it should be a pretty close approximation.

"A more precise option is that Photoshop can show you which colours are out of gamut for the printer and paper that you're using. Problem colours can be highlighted in grey or red, for example, as a warning. Even so, it's a rather blunt tool and you won't know if colours are only very slightly out of gamut or way off. In the end, there's no substitute for creating test prints, so that you can see exactly what you're dealing with."

PPL's powerful Pattern Print feature enables you to produce a test print with a series of thumbnails of your image, so you can compare and assess different brightness, contrast and colour balance settings without using up too much costly photo paper. Then you simply choose the thumbnail that looks most accurate or most pleasing, take a note of its reference number and input that back into PPL, which will apply the corresponding settings for your final, full-size print.

In PPL, Photoshop and other software, you can choose how to deal with out-of-gamut colours (colours in the image that fall outside the printer's range of printable colours) using the Rendering Intent setting.

Perceptual aims to preserve the overall visual impression of colours in the image. Any out-of-gamut colours will be adjusted to the nearest printable colours, and other colours may then be adjusted to preserve the relationship between all the colours in the image. The problem is, if all (or nearly all) the colours in your image are in-gamut, the image might be desaturated unnecessarily, and saturated colours in particular can be significantly dulled.

Relative Colorimetric will adjust only colours that can't be printed, leaving other colours untouched. This may result in slightly less saturated colours, but (assuming that not too many colours in the original image are out-of-gamut) brightness values will on the whole be more stable than if you use Perceptual.

So a good strategy is to check how much of the image is out-of-gamut first, and if there is a lot in important areas of the image, use Perceptual. If few colours or few areas are out-of-gamut, then Relative Colorimetric will alter the image less.

If you opt to use Relative Colorimetric, consider enabling Black Point Compensation to adjust the tone of the image so that the darkest point in the image matches the darkest point of the printer's ICC profile. It should not be needed if you choose Perceptual, because Perceptual is black point and white point relative. It should also not be required if you're using Canon papers and the built-in ICC profiles, Canon says. The consensus, however, seems to be that Black Point Compensation should do no harm and could help you achieve richer blacks particularly if you're printing on very absorbent papers.

"The more you print, the more experience you'll gain," Keith concludes. "And if you can't get the results that you want for any specific image, then you might be better off switching to a different paper with its separate, unique ICC profile."

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