Color To Black And White: A Simple Tutorial (Updated for iPhoto, Etc.)

Since I'm in tutorial mode, I thought I'd go ahead and post my method for converting color images to black and white images. I must add, too, that this image manipulation is like all the others: highly subjective. What I present here is a basic, simple, common denominator type of technique that yields near "perfect" (whatever that means) results every time, for every image. Our source image is a picture of a rose that bloomed in my back yard last summer:



As pretty as it is, I want to make it black and white — but before I do that, I make sure all the levels are properly set in the color image as per my previous tutorial, Level Correction. Once that's done, I'm ready to manipulate the image. First, though, I'll deviate from my Always Use Adjustment Layers Rule and make a copy of the source layer instead. Trust me, I have my reasons.

Now we fire-up Photoshop's Channel Mixer. Once open, be sure to check the Monochrome check box, and then enter the mysterious values of 30%, 59% and 11% in the RGB source channel boxes, like you see below:



Where do these values come from? In the simplest of terms, those values represent the most balanced tone levels the human eye can see, meaning, that combination is the "perfect" mix. It's also an industry standard and a great place to start.

Back to the manipulation. Below you see the results of the channel mixer change we just performed:



This image isn't too bad as it stands, but let's make sure it's as good as it can get. There's a bit too much gray contrast, which tells me we need to set the white and black points via the Levels control. So, we fire-up the Levels setting and we see the following:



Just as I suspected, the white and black points need to be modified — and we make this modification like we do all level adjustments: moving the white and black point anchors so that they rest where the data begins. Being able to do this is why I choose not to convert images to black and white via Adjustment Layers. If you do, you lose the ability to tweak the gray histogram like we're doing now.

So, I make my adjustments and the modified histogram looks like this:



With that done, I've successfully converted my colorful rose into a potent black and white image — all in a matter of seconds and without too much fuss or hassle. Neat, eh?

Here are the modified and original images for comparison:




Here's the same image with a larger view of the rose itself so that you can better see the texturing and shadows:




From this point, if you know how to use them, you can further enhance the black and white image by using Photoshop's Dodge and Burn tools. With those tools, you can really add contrast and definition to certain parts of the image.

But of course, Photoshop isn't the only program that can give you the ability to really tweak a color image into a black and white image. I'm using Aperture for most of my image processing now, and it works the exact same way — but all in one window. Here's what Aperture's Channel Mixer and Levels look like (notice Aperture defaults to the 30-59-11 values):



And those of you that are still deciding whether or not to upgrade to Photoshop and/or Aperture can still get some decent power with good ol' iPhoto. Take a look at this screen shot of the Adjustments window:



First off, DON'T use the built-in Black and White setting — that's cheating! What you do is move the Saturation slider all the way to zero (left) and all the color vanishes from the image. What's left is the Blue channel's histogram (though I can't find any documentation to state that it really is just the Blue channel data). Now, pop to the Tint slider and try various settings until you think you have the overall look you're going for. Lastly, adjust the Levels sliders to set your image's black and white points.