Calibrating your Workflow

Calibration: a bit off-colour Have you ever tried printing your own photos, and wondered why the colours were a bit off, and it was a bit lighter or darker than you remember? Then you’ve probably not been calibrating your workflow.

There are basically three pieces of hardware which control the final appearance of your print…

1. Your camera
Your camera records Red, Green, and Blue images, and they are processed into a single RGB image. Different cameras and converter programs have slightly different characteristics, producing subtly different colours.

2. Your computer monitor
Your monitor is the opposite of your camera’s sensor. It takes an RGB image and converts it into Red, Green, and Blue light. Every monitor is different, and produces subtly different colours. You can adjust the appearance of the display hugely using its controls.

3. Your printer
Once you get the image looking right on your monitor, you send the image to your printer. Printers use subtly different inks on subtly different papers. Each paper has its own colour-absorbing characteristics. Printers come with software which tries to use the best method of printing with your chosen ink/media.

Whilst each device is fairly good at reproducing colour, they are not perfect. Each stage of the process introduces errors, which accumulate towards the final stages of reproduction. Although it’s impossible to get around this, you can minimise the errors…

a. You can’t calibrate your camera accurately if you shoot JPEG—although you can make small cast adjustments on some models.
If you shoot Raw, you should be able to calibrate your raw converter software with a colour patch card, producing more accurate colours.

b. Most people know about monitor calibration, but most people don’t appreciate how crucial it is to photographic processing. If you can’t be certain that what you see on screen is how your image will look to everyone else, then everything you do is guesswork.
Monitor calibration with a colorimeter is a two-stage process. Calibration guides you through optimal monitor adjustment; and profiling produces a graphics card adjustment and custom colour profile for your colour-management-aware software (like Photoshop).

c. Printer colour profiles are often supplied with printers. These small files are installed on your computer and your colour-management-aware software uses them to generate your final print. Unfortunately, they are only good for specific paper/ink combinations. If you’re lucky, paper manufacturers might supply their own colour profiles for your printer. If you start buying 3rd party ink, you risk throwing all this precision out of the window.
You can side-step all this ambiguity and do-it-yourself. A printer calibrator will produce test prints and scan them to make a custom profile for every paper/ink combination you use.

Alternatively, you could just cross your fingers.

Keith Nuttall, 2011

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