Colour Images

If you have come directly here and skipped the mono section because you only want to work with colour images, please go back and work through the mono section first as operations and concepts discussed there are also important for colour, these parts will not be repeated and I assume that you’ve understood and assimilated the concepts from the monochrome section.


Visually most of us are stimulated by colour, more so than shapes. It is what makes black and white photography so difficult – we see the colours, forget about the shapes and composition and then are disappointed when we view the results. Applying these transformations gives us an opportunity to work with colour and make it the primary feature of an image, rather than a supporting feature where shape and composition are the keys to the image. As in monochrome Sabattier effect images, colour ones rely less on composition and more on the effect itself.


Image selection is similar to monochrome, so will not be covered again. A number of interesting effects are possible with colour images –they can become single colour images, single colour images with details in different colours, the image can become 2 or more key colours with a few other details, rainbow effects can be introduced, the limit is, again, your imagination.


There are quite a few ways to achieve interesting effects in colour. Grey/tint transform, color/curves transform, colour/correction transform. Each has its uses, the colour correction is most useful for fine tuning as a second step, while grey/tint forms a possible starting point for converting monochrome images to colour. Probably the most powerful is the Color curves transform, which allows us to control Hue, saturation and brightness independently of one another – it also gives us the alternative opportunity to work in the 3 RGB channels independently.


Before starting with colour images, make sure that you are happy with the concepts of inversion, control arrows, transition points and anchor points that were covered in the monochrome section before proceeding. They are fundamental to the process of colour manipulation as well as monochrome manipulation. In fact many successful colour images can be created using the monochrome techniques outlined above on the brightness channel of the image (V in HSV). I also assume a good working knowledge of the concepts of the different colour space models, particularly RGB and HSV, although some pointers will be given. If you are not too sure about colour spaces, look up the discussion on them in the PWP manual (if you have trouble finding it, there’s a link in the color curves transform pages). It is straightforward, but you do need to know about it.


Do not forget to assess the colour image before you start work on it.