Utilizing these founding color principles, the channel mixer puts theory into action. With the same effect color filters produced, you can dynamically interact with the translation of the spectral relationships between colors in the conversion process by mixing the individual channels within a document. The Channel Mixer tool allows you to control how much each of the three color channels (Red, Green and Blue) contributes to the final grayscale brightness. This method, therefore, has the ability to act as a digital set of black and white filters, all in a single interface allowing you the flexibility and power of having the whole color filter pack in post production.

The channel mixer has been traditionally and undoubtedly one of the most powerful black and white conversion methods; however, it may take some time to master since there are many parameters which require simultaneous adjustment.

There are many ways to mix the channels in this process, and the “right” mix will vary on a per image basis. Photoshop CS4 provides a few great presets to start with (in fact you can save your own) but it is important to play with the mix until you find a pleasing effect.

© Leslie Alsheimer

© Leslie Alsheimer

Pre-Channel Mixing:

Step 1: Open an image that is in RGB color mode.
Step 2: Analyze the channels (Note: this step is for viewing purposes only).
Open your Channels palette and click on the individual channels by clicking on the words “Red,” “Green” and “Blue”. These different views will provide a guide for how to customize the black and white conversion.
You will select the channel with the most detail and tonality to be the dominant channel for the channel mixer on an image by image basis. The Red channel typically contains most of the detail in the image. The Blue channel typically contains the luminosity, skin tones and contrast but also frequently the most noise. For this image, the Green channel was selected.
**Be sure you click back on the RGB letters at the top of the Channels palette to return the image to color before moving to the next step.

Channel Mixer: The Method

Step 1: Choose Channel Mixer from the Adjustment panel, or from the Layers palette, by clicking on the adjustment layer icon at the bottom of the Layers palette.

Step 2: Check Monochrome
Check the box next to the word “Monochrome” in the lower left-hand side of the Channel Mixer box. The image will immediately turn to grayscale. The initial mixture predetermined by default, as of Photoshop CS3, opens with Red 40%, Green 40% and Blue 20%. These better default values are actually another cool new feature as of CS3, as CS2 used to just map to 100% Red. Photoshop lessens the amount assigned to the Blue channel because the Blue channel typically holds more noise than the other two channels of Red and Green.

The advanced user may wish to monitor the Histogram palette in this process.

Step 3: Make Custom Changes
Adjust the Red, Green and Blue sliders to add and subtract amounts or percentages of each channel to produce an image to your liking. The choices made are purely aesthetic. The user has complete control of how each channel will be represented in the final image outcome.

For an even more pronounced effect, some colors can even have negative percentages.

It is advised that the percentage totals should not exceed 100%, when all three channels are added, in order to maintain the density or overall brightness of the image, although creative interpretation should always take precedence over numbers. Experimenting with diff erent color settings will enable you to find the combinations that your prefer. Be mindful though, if the number totals do equate to over 100% there is a risk of losing highlight information. Notice how cool Photoshop is to provide us with a Calculation Total feature at the bottom of the channel sliders! So fabulous not to have to do all that math on the fly!

Other cool new Channel Mixer features in Photoshop include the ability to save, load and share settings and presets.

Note: Be careful of the Blue channel as it typically holds more noise than the other two channels of Red or Green. Unless the goal is to create a grainy-looking image or some exaggerated effect, it is best to steer clear of using too much Blue channel in the mixture.

Step 4: Click OK when finished.

Note: Curiously, the image will not return to Color if the Monochrome button is unchecked. To reset, hold down the Option key and the Cancel button will turn to reset.

Step 7: Play!
There are as many interpretations of how an image can be conveyed as there are number combinations within the tool. Create several different interpretations and decide which one you prefer the best!

Note: A close approximation to the luminosity perceived by the human eye would be settings of red = 30%, green = 59% and blue = 11%. An approximation to the default grayscale mode change might be red = 60%, green = 30% and blue = 0%, and a mix of red = 34%, green = 33% and blue = 33% is the approximate equivalent to desaturation.

Digital Like Film
For some digital photographers, the ultimate goal is to create black and white digital images that look as if they were captured on film. The gritty quality that came from pushed Kodak Tri-X film sometimes seems aesthetically so far removed from the crisp digital files we see with today’s high resolution cameras. There is a unique elegance in film’s simple grain and mysterious qualities. For the film photographer, certain specialized looks have always been achieved by choices in chemistry, paper and technique coupled with the type of film or emulsion chosen. The varying diff erences in the consistency of light sensitivity in emulsions typically give each type of film its unique aesthetic. With many films being taken off the market today, it is still incredibly useful to keep those traditional names and what they meant to the film photographer alive, and use them as points of reference. For the black and white photographer, whether traditional or digital, using black and white effectively is about choosing a “look” that matches your image and intention.

Film stocks replicated from the Channel Mixer!
Of course, you will still have to add noise and grain to achieve the “look” of some films.

This method, patented as “The Russell Brown Tonal Conversion Technique”, lays the foundation for Photoshop’s latest Black and White stand-alone feature. This method uses two Hue/Saturation adjustment layers to make the initial conversion and creates a customized set of color mapping options at the same time! How does it work?

© Leslie Alsheimer. Before

© Leslie Alsheimer. After

Step 1: Open an image you wish to convert, and click the Adjustment panel and choose Hue/Saturation. You can also choose the Hue/Saturation adjustment layer icon at the bottom of the Layers palette, or go to the Layer Menu > New Adjustment Layer > Hue/Saturation. We are going to work with this layer later. So when the dialog box comes up, do not make any adjustments. Just click OK.

Hint: It is always a good idea to name your layers! Double-click on the letters in the Layers palette that spell out “Hue/Saturation” and type in a name like “Color Mapping”. This will help make it easy to remember what each layer does when you come back to the image later.

Step 2: Change the Blend mode of this new adjustment layer from Normal to Color. This option is one of 20 or so available blend modes from the dropdown menu in the Layers palette. This blend mode will allow us to adjust the hue and saturation simultaneously. (If we think about this technique in photographic terms, this layer will act as our Filter layer, or the Remapping color layer.)

Step 3: Make another Hue/Saturation adjustment layer by clicking on the Adjustments panel, or adjustment layer icon at the bottom of the Layers palette and choosing Hue/Saturation a second time. This time, however, we will pull the saturation slider all the way to the left, reducing the saturation to –100 (in photographic terms again, this will be the “Film” layer, or simply “convert to gray”).

Step 4: Now we are ready to create the black and white conversion dynamically by playing with the individual color channels within the Hue/ Saturation dialog box’s drop-down menu. Here’s how...

Step 5: Double-click the adjustment layer thumbnail icon on the middle layer in the stack, which is the “Filter” layer, or the first layer you created and set to color. This will reopen the Hue/Saturation dialog box. Adjust the Hue slider and notice how you are interactively changing the spectral relationships between the colors as they translate into black and white. Isn’t that cool?

Step 6: You can also play with the Saturation slider and make further adjustments to give more emphasis to tonal values within the image.

Step 7: This process actually gets better, believe it or not. If you go to the Edit Menu in the very same dialog box and click on the drop-down menu, you can change the “Master” composite to isolate each color separately. Pull both the Hue and Saturation sliders for each color independently. Watch out for unwanted posterization effects as this can happen fairly easily if you are not paying attention.

Extra Bonus Tip! You can also expand the color range of the sliders by using the eyedroppers. If you have some red in the image and you wish to add yellow and green to that adjustment area, select the “Add” sample eyedropper tool and simply click on the colors you wish to add, such as blue and green. The tool will expand the range of colors and result in better blending values.

© Leslie Alsheimer.

Coined by Nigel from the film This is Spinal Tap, this pop culture phrase commonly refers to anything capable of being exploited to its utmost abilities, and to exceed them. In other words, it is the act of taking something to an extreme. Coincidentilally Photoshop CS4, code name “Stonehenge”, also pays homage to Spinal Tap. So this technique is an 11: The ADVANCED Maximize Detail Combo Conversion Technique! To the MAX!

Once you have explored the fundamental conversion methods, you may be ready to delve deeper into the conversion process. If you have not noticed yet, converting to monochrome is most notably about re-establishing the spectral relationships between color and tone within an image. The advanced printer will know that image detail plays an integral role in successful black and white fine art print making. Be warned this fancy technique takes a fair bit of time, is not simple and can be incredibly confusing. It does, however, maximize your control over the conversion process, whereby allowing the user to selectively maximize detail and tonality in the conversion process. Althought there are a few variations on this technique, no other method quite matches its power, as this one really does go to 11!

© Leslie Alsheimer.

Step 1: Begin with an RGB image file processed optimally for color. Duplicate your image. Image Menu > Duplicate. Open the channels palette and analyze the channels by clicking on each of the individual channels in the Channels palette. Do this several times and make notes on the differences in how each channel translates the information and detail. For this image, I noticed that there was more detail in the doorway (where the man is standing) in the Blue channel, as well as in the top of the window. In the Green channel, there was more information in the flowered curtains, the girl’s feet on the bed, and the skirts they are wearing, as well as with the flip-flop on the floor. The Red channel holds more detail in the empty beds.

Step 2: Convert the Duplicate Image to Lab mode.

Step 3: Go to the Channels palette and click on the Lightness Channel. Select All > Edit Copy.

Step 4: Reactivate the original color image and create a new layer. Layer > New Layer, or click on the new layer icon.

Step 5: Edit > Paste the Lightness channel into the new layer and rename the layer “Lightness”.

Step 6: Create three more empty layers and rename them “Red,” “Green” and “Blue.” You are going to copy and paste each of the Red, Green and Blue channels into these layers.

Note: You will need to retarget the Background layer and the corresponding channel each time you want to copy a channel.

Step 7: Turn the visibility off on the Lightness channel by clicking on the eyeball next to it in the Layers palette. This will ensure that the Lightness channel will not affect your channels. Copy and paste each channel into the appropriate new layers you have just created.

You can make excellent conversions by simply lowering the opacity of the different layers at this point. But who is stopping there? I said this one goes to 11!

Step 8: Add a “Hide All” layer mask to each of the Red, Green and Blue channels. Do this by holding the Option key as you click the “Add Layer Mask” icon in the Layers palette, or simply use the Layer Menu > Add Layer Mask > Hide All.

Step 9: Use a paintbrush, set to the default colors of black and white at various opacities, and hide or reveal the diff erent aspects in which you noted. I revealed the doorway on the Blue channel, the curtains, feet and skirt on the green channel layer and the empty bed detail on the red channel layer.

Try this technique with images shot in low light. The blue channel is great for bringing out lost shadow detail. But be careful, as it also holds the most noise!

© Leslie Alsheimer.