In our page on Colour Management and its importance we explained how devices like cameras, scanners, monitors and printers display colour using different methods - in fact display the same colours differently. To put it another way, the same RGB numbers in an image file look different when displayed on different devices. In fact some devices may be incapable of representing the colours at all.

We went on to say that colour management systems use ICC device profiles to:

• Match colours across all the devices in your workflow, e.g. camera(s), monitor(s) and printer(s), so that colours look the same on each device; and
• Preview colours on your monitor so that you don’t include colours in the final image that our printer (for example) can’t reproduce.

 Now we need to go a little further and arrive at a definition of Working Space, which is the range of colours (or colour space) that you instruct Photoshop to use by default when you’re working with images.

Why working space is so important

Understanding the concept of Working Space is important if only because there’s widespread disagreement on the subject!

Not all colour spaces are created equal. Using a too restrictive colour space can degrade your images, so you can’t take full advantage of your camera or printer’s capabilities. But “wide-gamut” colour spaces can be problematic too.

It’s also important to understand Working Space so you can set up policies around it. If you don’t, your colour management systems will fall apart and/or you’ll come to grief when exporting your images and layouts from Photojunction.

Click here for more about Photojunction and colour management.

What we recommend

We recommend that you adopt EITHER Adobe RGB (1998) OR sRGB as your working space. If you asked us to chose, we’d go for Adobe 1998 because of its bigger colour gamut.

Adobe describes Adobe 1998 as “the largest recommended RGB working space and suited for print production with a broad range of colours”). That's why, in the eyes of some people, sRGB’s smaller gamut may compromise quality. We really don’t want to take sides in the debate. Sufficient to say, if you use Adobe 1998, great. If you normally work in sRGB, that’s OK too: just send us your sRGB-profiled prints. 

Certainly, don’t bother converting your sRGB files to Adobe 1998 just for us (and remember, if you do, “convert”, DON’T “assign” - there’s a big difference!).

For instructions on how to set up Photoshop with either Adobe 1998 or sRGB, click the appropriate link:  Mac / Windows

What follows will explain basic concepts about colour spaces (including what is meant by “Working Space”). We need to start by defining some terms.

Colour space

A colour space is a range of colours in the visible spectrum – in other words colours we can see (most of us anyway). Real world colour spaces don’t show the whole spectrum because real devices can’t portray all the colours that our eyes can see. These colour spaces are described (or “mapped”) by ICC profiles.

Some colour spaces are “device-dependent” (for example the range of colours that your camera can capture, or your monitor display, or our machines can print). Some are “source profiles” (eg for cameras and scanners), others are “output profiles” (eg for monitors and printers).

Other colour spaces are device-independent. In effect these are colour specifications, like Adobe RGB (1998) or sRGB. It’s a colour space like this that we’ll need to select as our working space.

Colour “models”

Colour spaces can also be classified as variants of one or another colour model. For example “Lab colour” describes all the colours that a person with normal vision can see (the “visible spectrum”). Lab colour is device independent, or rather the “device” is the normal human eye (it also describes colour with a different set of values from RGB). We’ll explain how Photoshop uses Lab colour in a moment. “CMYK” colour spaces are based on combinations of ink and paper and are irrelevant for our purposes. Avoid them! Instead, the appropriate colour model for us is RGB.

Calibration, ICC profiles and colour gamut

As we’ve said, devices like cameras, monitors and printers each have their own colour space. These spaces need to be taken into account down the line by other devices displaying and eventually printing the same images.

The calibration process creates ICC profiles by mapping the way devices capture, display or print “standard” (ie known) colours. Photoshop uses these profiles to translate colour values from one device-dependent colour space into Lab colour and then out again to be displayed or printed on another device. The result is, despite the bias in each device, that the colour always appears the same to our eyes.

Click here for calibrating your monitor.

In the illustration below, the left-most graphic represents the entire spectrum of colour that the eye can see (ie the entire coloured area in the graphic). But no device can capture or display that entire spectrum. There is always something lost. The other graphics represent the fact that each device in your workflow will be capable of capturing, displaying or printing only part, and a different part, of the spectrum. The part that it can capture or portray is called its colour gamut.

Working space

When we use Photoshop we need to choose a “working space”. This is the colour space into which Photoshop will, by default, convert your images when you open them for editing. Remember, there’s no point attempting to work with colours that your camera can’t record, your monitor can’t display or your printers can’t print. You might think therefore that your working space should be the “lowest common denominator”, a gamut that includes only those colours that all your devices (and ours) can deal with. That may be why some labs suggest that you use sRGB as your working space (line B below).

Adobe’s description of Adobe 1998 as “the largest recommended RGB working space" suggests the opposite approach. Your working space will NOT be the limiting factor that unnecessarily “clips” your colours (line A above). Put another way, you’ll lose less colours in the editing process. However you'll need to “preview” the image on-screen in order to see how it will appear when we print it. That’s because our printer gamut (any printer gamut) will be smaller than Adobe 1998. If you don't do so, you could be disappointed.

Out of gamut

If you choose a working space with a smaller gamut than your camera can record, colours that fall outside the working space will not be able to be displayed. They’ll be “out of gamut”. Obviously the smaller your working space (sRGB instead of Adobe 1998, for example) the more colours will be out of gamut.

Photoshop can’t just ignore these colours, though, it has to change them to something that can be displayed. You have a choice of how it goes about this, and what you choose is important. You do so by selecting what Photoshop calls a Rendering Intent.

Rendering Intent

You will recall that when we outlined how to set up your colour settings in Photoshop, we recommended that you select Intent: Perceptual.

Like the other Intent options, “Perceptual” ensures that all colours are “in gamut”, but in the process it shifts ALL the colours slightly so that the differences between them remain. If Photoshop only changed colours that were out of gamut, the result would be “blocky” areas all with the same RGB value. In other words, you’d lose detail.

By the way, Perceptual is appropriate where you are converting to a smaller colour space (eg from Adobe 1998 to sRGB). It is not appropriate where the destination space is larger. In such cases Relative Colorimetric will generally be the correct choice.

About sRGB

You may have noticed that many Labs recommend sRGB. We think this is partly based on the mindset that photographers need to do their own colour correction in the digital age. The unfortunate fact is that many people (including some labs) probably don’t have a sound understanding of colour correction or colour management.

When things go wrong, because things do go wrong, who’s to blame? Everywhere photographers are either complaining about their labs or wondering what they’re doing wrong themselves - because what they see isn’t what they get!

In a way sRGB minimises these problems. Because it is...

• based on the characteristics of the average PC monitor
• a small colour space, and
• becoming the default for many low-end printers

…the chances are higher that what the lab can print will match more closely what you see on screen. So the upside is the lab gets less complaints. The downside is the quality may be reduced.

If you bought a high-end camera (and we bet you did), the chances are good the manufacturer doesn’t want you to use sRGB. That’s because you’re throwing away so much of the colour the camera can capture. For the same reason, what’s the point of capturing in RAW and then converting to sRGB?

The screenshot above illustrates the point. It shows our Monitor Test Image (Queensberry.TIF) set to proof in sRGB, and with Photoshop’s Gamut Warning turned on. The grey areas show colours that can be printed on our machinery, but don’t fall within the sRGB gamut. To be fair, almost all of the rest of the test image is “in gamut”, but this does illustrate the point that using sRGB as your working space can lead to an unnecessary loss of quality.

We don’t recommend preserving the image’s ICC profile

In Photoshop you can choose to preserve the embedded profile of an image instead of converting it to your Working Space (under Colour Management Policies, “Preserve Embedded Profiles”).

We do not recommend doing so because it will cause practical workflow problems later. (Click here for Photojunction and colour management .)

Previewing (Softproofing)

It should also be clear by now that your image file created in the Adobe 1998 colour space may have colours that you can’t print. So that you know what the print will look like, you will need to view it on screen in “preview " mode. Click here for more.