Digital Color Management

In the ‘good old days’ you looked at your slide and that was the color.

True, you could influence color by your choice of film stock. Kodak was neutral, Fuji exaggerated the blues. The discerning photographer might also choose a particular color lab that was known to run slightly blue. But basically what you saw was what you got.

When making prints the printer could also influence the final color but, assuming that a color match was the objective, both Cibachrome or R-type prints looked basically the same.

That was due in part to being within the same RGB color space. The problem for digital workflow is that digital camera users might start off in an sRGB color space but end up printing on CMYK inkjet printers.

Digital Color

In order for your prints to look like your digital images, with faithful color reproduction, you must manage color throughout the process of capture, editing, and printing.

The problem is that an image can look different on different monitors as well as printed on different printers, thus adding an extra layer of complexity. ICC profiles are the industry solution to address this problem – as we shall see later.

First we must accept that devices, drivers, operating systems, and applications all interpret and reproduce colors differently.

This is because Input devices (scanners and cameras) and output devices (monitors and printers) all have a different Gamut.

A transform is needed to map the colors from one (source) device color space to another (destination) device color space. Transforms are either device dependant or device independent.

Device dependent color transformations are primarily used in high-end proprietary systems. However, the average consumer will mix and match their devices and so rely on device independent color spaces.

The rest of us ‘joes’, who mix and match our brands, are not so lucky!

ICC profiles

For each device there needs to be a transformation - from that device into a standard color space.

The transforms from device into a standard color space are embedded in a file with the extension ‘.icc’ - this is the ICC profile. This file gets tagged onto an image (not RAW files) to act as a reference wherever that image goes afterwards.

The ICC profile allows the white point of the medium and illuminant to be mapped; the full gamut of the image is compressed or expanded to fill the full gamut of the destination device.

ICC profiles allow vendors to register the unique signature of a device. ICC profiles also allow users to retrieve this information from a number of places.

ICC profiles usually ship with the camera software. If you require an ICC profile search the web for it! There are loads of sites with downloads.

More info www.color.org