Amateur Indiana

[bsphoto]

It seems like you can't pick up a digital photography magazine without an article on how to convert pictures to Black & White. But in case you missed one, I thought I'd write my own here. I also use Photoshop CS2, the latest and greatest, but for those on a lesser budget I'll try to come up with some workarounds. Of course you're more than welcome to contribute via comments in this thread.

This is going to be done over time, with many edits, so check the date.

Here's the original image.



You can see I've pasted a color wheel on this picture so we can see what happens to pure red, green and blue when we play with the picture.

First, let's get this out of the way. The worst way possible to convert a color picture to B&W is also the easiest. That's hitting the desaturate tool in your favorite editor. In Photoshop that would be Image > Adjustments > Desaturate.



In color terms, saturation referrs to how pure a color is, or how much gray in proportion to hue. (A color being made up of hue, saturation and brightness.) By desaturating you set that value to 0%, which is all gray. That produces an undesirable result.

The next easiest way to convert to B&W is by converting to grayscale. That's better than desaturating, but it converts each image in the exact same fashion. It also throws the color away and some features don't like grayscale files.



So with a lack of control, grayscale is less desirable.

What we want is a conversion which gives us control of how the pictures are converted AND a way to change that conversion later on if we should so desire.

Photoshop gives us both by using Adjustment Layers and the Channel Mixer

Adjustment Layers do same thing as most for the things on the Image > Adjustments menu, except the applies them to a layer rather than to the image. By putting them in a layer you can turn them on or off and make changes to them. Since they are layers, they do not affect your original image, and they also use layer masks so you can apply the effect to just part of the image.

You create an adjustment layer from the layer menu, that would be Layer > New Adjustment Layer. You can also click the new adjustment layer button on the layer palette. You'll note that many of the same commands in the image adjustments menu are there, but not all of them.

We want to use the Channel Mixer adjustment layer.

Computer images are sepeated into channels, one red, one blue and one green. Combined these make full color images. What the channel mixer does is allow you to specifiy how much of each channel is used to make up an image. You could take out all the blue for instance, or only use the red.

Not all programs have a channel mixer. Photoshop Elements for example. You can download plug-in channel mixershttp://www.earthboundlight.com/phototips/photoshop-elements-curves.html
Or you can use a combination of two adjustment layers.

Use some other program? Feel free to comment and tell us the technique here.
_________________
Bill Sylvester
bill@wkrp.com
http://bsphoto.wkrp.com
http://blog.myspace.com/bsphoto