Fuji X-Pro1

The most basic of these would be converting images destined for the web from wider gamuts to sRGB, or more specifically, THE standard for web colours. In this process, you basically take a file format that supports alternative colour spaces and compress those colours into a smaller sRGB colour space for use with JPEG images. During this compression process, colour information is lost from the original and steps in gradients will become less smooth, this is an example of lossy compression. Now for the most part this isn’t a problem, edit using the widest gamut available and then down sample to a smaller gamut when outputting to a specific device or medium. There is enough information available that gradients, even though less smooth, probably won’t have any perceptible degradation in quality as long as a close-enough in gamut colour can be found for the out of gamut equivalent.

Additive vs Subtractive Colour

That highlights one issue, difference in the colours (gamut) that can be reproduced. The second issue is the different ways in which colours are formed when using different devices. For digital displays it is typically Red, Green and Blue (RGB) values that mix together to form a colour  The starting point is a black background and colours are added together to get lighter and lighter shades until eventually the values are fully saturated and a solid white is produced. Basically a new portion of visible spectrum is created and projected as needed. For physical output devices like printers, the process is generally reversed. The starting point is a white background and colours are added until eventually a solid black is formed. The full visible spectrum is projected onto the final medium by sunlight or artificial light (we’ll talk about colour bias much much later) and the reflected visible spectrum is altered by the medium to remove (or filter out, like a colour filter) parts of the spectrum and shift the colours that are seen. This process is based on Cyan, Magenta, Yellow and Black (CMYK) to produce the final colours......

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The chart is only intended to be used as an example. It contains several useful colour references though. Firstly we have black and white reference points, with Yellow, Magenta and Cyan in between. These form the important colours that require no or little mixing of ink (CMYK ink printer). Then we have Blue, Red and Green values on either side, providing a reference points for mixed colours. The left hand side is more saturated and more luminous than the values on the right. I’ve also included a gradient from black to white, since most printers form grey by mixing colour inks, we should be able to see any colour shift in this area. For the tests I used a calibrated monitor and a single printer and paper type. All images were then scanned in and not altered (except for the conversion from TIFF to JPEG for web use). Printing was done from Photoshop CS5.5 and Perceptual was used for all images. I also selected to not allow any black point compensation except for the marked the single image that is tagged to have black point on.....