B&W

[croos]

Are there any tips about how to accomplish a pleasing black and white conversion with PWP? I often think digital B&W looks pretty dull, especially my own tries. I'm aware of the plugins for different programs, but apart from not having the programs in question I'd like to figure out how do to it myself, so to speak.

A more general question. When you want B&W is it a good idea to edit the colour image first so it looks good (saturation, sharpening, whatever one usually does), or is it better to take it directly from a "plain" raw conversion to B&W?

[jsachs]

Good question. This topic probably deserves a separate document with some detailed examples, but here is a brief summary of the techniques I regularly use.

To answer your second question first, increasing saturation before converting to B&W could be helpful as it increases the separation between the color channels, but everything else works more or less the same in B&W or color.

To exaggerate the differences between different colors when converting to B&W, I use either the Channel Mixer or the Hue Curve method. When using the channel mixer, you can get effects beyond what you can get by just applying a color filter to the image since it allows for negative slider values. For example:

B&W1 v1.jpg (102.48 KiB) Viewed 83 times

Similarly, using the Hue Curve method, you can selectively lighten or darken different colors in the input image by dragging the curve up or down for the hues you want to affect. Just be aware that these techniques and generally anything else that increases contrast will also amplify noise.

Once you have a B&W image to use as a starting point, the next thing to try is the Brightness Curve transformation to make some tonal adjustments. While you can apply curves to the entire image, often the best result comes from creating a mask for some area you want to work on and then applying different curves to the masked and unmasked areas. The easiest way to create the mask is to use the Freehand Outline mask tool to make a rough selection and then to blur the mask using the Mask Blur tool so the effects will be applied smoothly. Next click the Histogram button at the top of the Brightness Curve transformation to display the histograms of just the masked or unmasked areas.

B&W2 v1.jpg (1.66 KiB) Viewed 83 times

Then when you click the white or black curve buttons you will see the histogram of the masked or unmasked areas and can modify curves separately for each. You can click and drag on the input image to see what part of the curve corresponds to its brightness levels. To increase contrast in that area, add control points to the curve and make the slope steeper. To make an area brighter, raise the curve -- to darken it lower the curve.

Finally, once you have made your local brightness and contrast adjustments, you can increase the local contrast for all or part of the image using the Multipass Sharpen transformation. Generally, just adjust the Blur Threshold -- increasing it makes the effect stronger.

Lastly, as with color images, you might need to do some cloning to touch up problem areas and cropping to fine tune the framing.

[Winfried]

Another way is the "Color Lookup" transformation.
But for this approach you will need LUTs (LookUp Table). You may find these for free in the on the Internet. There different formats for this files. The Cube-format is widely used.
You can even create your own LUTs with this transformation. I attach a Cube-file as an example.
It converts a (b/w)-image nearly like the Tint Transformation