B&W Conversion via LAB
There are so many ways to convert an image to B&W, each offering different advantages, disadvantages, look and feel. Personally, I find converting using the Lightness channel in the LAB colour mode gives me the most pleasing results for my portraiture.
- The first thing to do is convert the image to LAB colour mode (Image->Mode->LAB)
- Like RGB, LAB colour mode has 3 channels. However, the colour information is split into channels A and B, and the Lightness/Luminosity detail is contained within the Lighntess channel. It is this channel which is used for the conversion
- We need to remove the colour channels from the image. Some people physically delete both of them, but I find the easiest way is to simply select the lightness channel
- Then convert it to Greyscale (Image->Mode->Greyscale). Note: This is not the same as just converting an RGB image to greyscale
- The conversion is more or less done at this stage. But most people prefer to work with RGB images, so the next step in the conversion process is to convert the greyscale image back to RGB (Image->Mode->RGB)
- The image is now a B&W image back in the RGB colour space, ready for further processing.
- Personally I always find I need to boost contrast a little, so some curves/levels adjustment is usually required.
There are so many different ways we can convert an image to monochrome and generally I don’t subscribe to the idea that one way is better than any other. For different types of shots, I may use a different conversion technique. What I’ve shown here is the results of a number of common techniques (I forgot to add desaturate). I don’t detail how any of the conversions are done, but if you would like to know, please ask.