Home Newsletter Locations Diary

 Indexes

Portal
Magazine4U

Article

Colour Management

In the article Colour management outlined we looked at the impact of colour management on white balance choices. In this article I want to look at the total area of colour management, why it is necessary and what must be done in order to get perfect colours. Other articles link from this explaining how to actually do each of the steps involved.

There is not a lot of cost involved, and any printer including the cheapest can produce quality work if set up correctly and is using the right profile.

Why colour management is necessary

The world of photography has many changing variables, the colour of light, time of day, weather, reflected colours, screen settings, ink, paper used, printer, and more. If we ignore colour management the result we get is the sum of the inaccuracies, and in some cases we may get quite good colour representation and on others times be a long way out.

While its possible to get to know the inaccuracies and we find some people who will say, they have to look at it on the printer with some cast or other for it to print out about right, this is both not reliable and not standard with others. For example if you take a photo and edit it, and send it to a magazine, they should see exactly the same colours on their computer as you do and print them out correctly.

It should not be a case of if to use colour management or not, but your choice as to the level you go to on a specific day or task, with the knowledge of the effect. We need to therefore both understand the process and also understand when our clever cameras and other kit will get it right and when it won't. We will also need to decide when accuracy of colour is necessary to us, and for most accuracy will be important for some projects and not for some others.

The stages involved in colour management

Colour management in digital photography has 3 main stages:-

  1. White balance on the camera or a management routine that uses targets or other forms to allow colour to be taken and edited correctly.
  2. Correctly profiled screen, you can't make editing choices if what you see is not the image that you are going to get.
  3. Printers need accurate profiles produced for the individual printer, ink and paper chosen.

1st stage capturing the images with the right white balance.

We need to set the right white balance setting for the light conditions, this can be done in a number of ways, in some cases we can use auto white balance and allow the camera to take care of this for us, but if we are going to use this we need to know when this is not going to produce good results.

We have the following articles on white balance:-

Although white balance is important, you do have some leeway or recovery capability:-

  • Shooting in Raw format allows the white balance to be changed afterwards to any of the settings except PRE.
  • If you do make a mistake, for example leaving the camera on a PRE setting from a different light condition you can batch process to another setting appropriate to the conditions.
  • Once you understand white balance fully you have many more options, can design in changes or quickly correct any problem you experience.

It is however far better to take the image correct in the first place, and if you want very accurate colour then you need to use the PRE setting and this cannot be set afterwards.

2nd stage  getting the screen right

If you don't see on your screen the true colours of the image, then you will not be able to adjust it correctly and corrections you do make are likely to involve errors and results in less than reliable results.

You could think of a profile as a conversion table, when the part of the image is a specific colour the monitor has to show it with a specific adjustment so that it appears correct. This is not the same as shifting everything towards, blue, yellow etc, but making thousands of tiny adjustments to every colour.

The profile is a file that is used by your operating system and affects the way you see all images, in the case of PC users with two screens this is only correct for the first screen.

As screens come the colours look quite good, but they are set up primarily for data processing and office use, and like TV's produce images that are quite a way from accurate.

Profiling is done with a low cost device and software that anyone can manage. Screens should be re-profiled fairly regularly.

Screens should be used under consistent and suitable lighting conditions. If you have brightly coloured walls and surrounds you may also find it helps if you have a large grey sheet of card, some prefer black, for example mount board that you have cut a hole in to fit the screen, this then means the photo you see is being compared to the neutral grey and not in comparison to the coloured background. Some people also like to use 'white' or 'daylight' light bulbs, so as to have a consistent white or daylight light, some prefer to do their critical editing at set times of day when daylight is right. Some prefer a north facing window. Ultimately the objective is to see the correct colours and providing that there are not any extremes in lighting or background, just profiling will get you very good results.

We have an article that looks at the detail of how you go about screen profiling and where the profile lives within your computer. You will also find information on some of the profiling equipment available in the article Profiling Equipment.

Profiling the printer

You need a profile, for every combination of printer, ink and media that you use, by media we mean the paper or canvas that you are printing on, and its identifiable by make, brand within the make, surface, and weight. Normally different sizes of paper where all the other details are the same don't require separate profiles.

If you have looked at the media you are printing on then you will realise that they vary a lot, sometimes you are printing on paper, sometimes on photo paper, which has a plastic like surface and sometimes on canvas. Most people will recognise that these are different and will require different amounts of ink and combinations of colours to get good results. Ink and printers perhaps, some have more difficulty with, but there are considerable differences between inks in use, between printer models and often within individual printers within a model.

It is possible to download standard profiles, but our tests have shown that these produce results that while they look okay, are considerably inferior when compared to a print made with the same setup and fully profiled. We have tried using standard profiles and printouts from several fully profiled printers and found that the result on a cheap printer bought from Tesco for less than 30 and printing on photocopier paper can produce a more accurate image then a printout on the best photo paper on an expensive printer using a standard downloaded profile. The advantage with the better printer when it is fully profiled is better and has other benefits. However you don't have to spend a fortune on media or printers to get really good results.

Printer profiling is done by printing out a test print, which is a large number of small coloured squares, and then analysing this with a special device, and from this producing the profile. Its a little more complex than the screen side, and you also need to know both how to use this profile with each of your printing programs and how to set up your printer driver to get the best results. While screen profilers are very low cost, printer profilers are a lot more expensive and most people won't need more than a few profiles, so its often not worth tying up the cash in this, as you can post in the test print and get someone else to produce the profile for and send it back to you. There are number of people that provide this service, and they charge typically 25 to 40 a profile, and you can find them online doing a web search.


See Also:

We have the following articles on printer profiling, media, printers and suitable equipment:

Screen Profiling

Printer Profiling

Profiling Equipment

Printing on a budget

Low Cost or No Cost Media

 


By: Tracey Park Section: Photography Section Key:
Page Ref: colour_management Topic: Editing, Printing and Publishing    Last Updated: 10/2011
.

This page:

Link directly to this page, with text or the button on right.

Text linking: Colour Management Explained on Photographers Resource

Linking Instructions                            http://www.photographers-resource.co.uk/

Photographers Resource, all the information for the photographer