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Color to Black-and-White Conversion

I have a fond place in my heart for black-and-white photography. Processing film and making prints in the darkroom is how my love of photography took root. The first time I saw a print developing in the developer tray, I got so excited that I immediately turned on the white lights to look at it. Yes, of course, the print turned black before my eyes, because I skipped the stop bath and fixer. Silly me.

I mention this because my love of black and white is what got me into photography, and now shooting digital has breathed new life into that love. Just to be clear, except for a few raw sensors and cameras like the recently announced Leica M-Monochrom camera, all sensors capture color when shooting raw. Some cameras allow you to set the in-camera settings to shoot black-and-white JPEGs, but the raw files are in color (well, more or less, as I discussed in Chapter 1).

In the old black-and-white film days, you could control the exposure and processing to adjust the contrast of the negative. In the digital age, this is done in Lightroom and Camera Raw when converting color to black and white—and you don’t need to mix any fixer!

It’s important to understand that black and white is a monochromatic representation of colored light. How that color is converted to black and white is fundamental to getting optimal conversions. Ansel Adams could develop his early film by inspection, because the film was orthochromatic (sensitive only to blue light) and he could use a bright red light as a safelight to see what was happening in development. Modern black-and-white film and digital sensors are sensitive to all colors of visible light (and, in the case of digital, very sensitive to infrared). The term for that is panchromatic (across all colors).

In the old days, photographers generally shot film using color-contrast filters to alter the panchromatic response of the film. They used yellow to lightly darken blue skies, red to really darken blue skies, green to lighten foliage and darken skin, and orange to lighten skin. With digital cameras, we don’t need to do that because we’re capturing full-color images and we can modify the panchromatic response of the sensor in post-processing (which, to an old dog like me, is pretty cool). In this section, I’ll talk about various methods of controlling the color contrast of the black-and-white conversions and also delve into the concept of color toning the monochromatic black-and-white conversion.

Adjusting the panchromatic response

When shooting digital, we end up with a digital negative that has color information: red, green, and blue color channels in the RGB image. If you look at an RGB file in Photoshop channel by channel, you’ll see that each channel has a different tonality based on the color of the light passing through the tricolor RGB sensor filters. Figure 4.50 shows the original color image and each of the color channels, as shown in Photoshop when selecting a single color channel. The dolls were shot at a flea market in Buenos Aires—I hope you don’t find them too scary (my wife thinks they’re really creepy).

04_50.jpg

04_icon.jpg COLOR IMAGE

04_50a.jpg

04_icon.jpg RED CHANNEL

04_50b.jpg

04_icon.jpg GREEN CHANNEL

04_50c.jpg

Figure 4.50 BLUE CHANNEL

Figure 4.50. Color image and red, green, and blue channels.

The key to converting from RGB color to black and white lies in understanding the relationships of color to grayscale tone. In the Red channel figure, you see the doll’s red bow tie is very light, while the same bow tie is darker in the Blue channel. Conversely, in the Blue channel, the blue hat is much lighter than the same color in the Red and Green channels. The Green channel, which contains the largest amount of luminance data (because of the RGGB Bayer pattern of the sensor; see Chapter 1), looks like a more general color to black-and-white conversion. As a result, when getting the optimal blend of the color-channel information to the single-channel grayscale image, you need to blend the various amounts of each channel to get a final result that maintains a good color contrast–to–grayscale conversion. It’s not at all unusual to have two different colors whose RGB appearance show substantial differences converge and appear much closer to a single grayscale value. That’s why we need to “twiddle” with the conversion. Figure 4.51 shows the result of a default conversion from color to black and white in the HSL/Color/B&W panel of Lightroom or the HSL/Grayscale panel of Camera Raw.

04_51.jpg

04_icon.jpg Image at normal Default blacK-anD-WhIte conVersIon

Click to view larger image

Figure 4.51

04_icon.jpg Image WIth the auto optIon

Figure 4.51. Comparing the default color to black-and-white conversion to the Auto option.

The Auto option does a fairly good job of maintaining good color-contrast separation in the grayscale tonality. You can see it’s pretty close to the Green channel in Figure 4.50. The Auto option is very image- and color-sensitive, but it’s often a better starting point than the zeroed default. That’s why I have my preferences set in the Lightroom and Camera Raw defaults to use Auto. Tuning the colors is an easy task if you click the Targeted Adjustment tool and use the cursor directly over the image to target specific colors to lighten or darken tonality. Increasing a color will lighten the tone, while numbers below zero darken the tone. Once you click the B&W button on the panel, you won’t be able to see the color image, but you can click the HSL or Color button to bounce back to the color version of the image. Upon returning to the B&W panel, your last-used settings will be remembered. I wanted to darken the blue tonality of the hat and lighten the red bow tie. Figure 4.52 shows the adjusted black-and-white color mix.

Figure 4.52

Figure 4.52. The final color to black-and-white mix.

To finish off the image, I added some local adjustments to soften the corners of the image. The mask in Figure 4.53 shows the areas I modified using the Adjustment Brush. I used two settings: Clarity was set to –100 to soften the contrast of the corners, and Sharpness was set to –100 to add a blur effect. Figure 4.54 shows the final adjusted image.

Figure 4.53

Figure 4.53. A mask that was created to adjust the reduced contrast and blurring in the corners.

Figure 4.54

Figure 4.54. The final image of the scary dolls!

Warm toning

There’s black and white, and then there’s black and white with a color tone. The concept goes back to the days of the darkroom, where a normal, neutral, black-and-white print would be processed in a chemical treatment bath after development and fixing—or simply printing on a warm-tone paper such as Agfa Portriga. When I was darkroom printing, the only time I didn’t used a chem-tone was when delivering commercial prints for reproduction. Normally, I would tone the prints in a KODAK Brown Toner, a KODAK Sepia Toner, or a combination of KODAK Rapid Selenium Toner and any of the above. The intent was to add a subtle color tone to the image and enhance the maximum density of the print. If the previous sentence is just gobbledygook, let me condense it: photographers like to add a subtle (or not-so-subtle) color tint to neutral black-and-white prints.

This warm toning example is of a boring color image shot of the steam engine of the Swangage Railway, which is a heritage railway running between the town of Swangage in the English county of Dorset to the ruins of Corfe Castle. Figure 4.55 shows the original color images.

Figure 4.55

Figure 4.55. The color image of the steam engine while facing facing south on the Corfe to Swangage leg of the trip.

I tried an Auto conversion to black and white in the HSL/Color/B&W panel and made some adjustments. The final settings were to darken the orange, yellow, and green colors and really darken the blue colors to enhance color contrast. I also added a Graduated Filter to darken the sky and Adjustment Brushes to lighten the steam. Local blurring was added to make the top and bottom of the frame softer. The initial warm toning was done with the Split Toning panel only adjusting the Highlights. Figure 4.56 shows the grayscale conversion and the initial warm toning.

04_56.jpg

04_icon.jpg COLOR TO BLACK-AND-WHITE CONVERSION WITH ORANGE, YELLOW, AND GREEN SET TO –25 AND BLUE SET TO –50.

Figure 4.56

04_icon.jpg WARM TONING SET TO A HUE OF 50 AND SATURATION OF 25

Figure 4.56. The color to black-and-white conversion with adjustments and the initial warm toning results.

I liked the vintage look the warm toning gave the image, but I decided to back down the saturation a bit and modify the Split Toning panel’s Balance to keep the warm tone from going too far into the shadows. For the final image (shown in Figure 4.57), I reduced the Saturation to 20 and moved the Balance slider to –50. This had the effect of not only reducing the overall warm tone but also making the shadows in the image more neutral. It’s always a temptation to overdo effects. Although I liked the warmer tone, I think I prefer the reduced warm-toning result. What do you think?

Figure 4.57

Figure 4.57. The final warm-toning result.

Split toning

I mentioned that I used to do a kind of split toning in the darkroom. The typical toning would be a combination of sepia and selenium toning. The sepia toning was a bleach and redevelopment to warm up the highlights and midtones while not impacting the shadows, which remained neutral. After the sepia toning, I would run the print through selenium toning, which added a deepening of the blacks and a cool purplish tone. I used to do this in a chemical darkroom, but you’re no longer constrained by chemicals, so you can use whatever split-toning colors and saturation you want in Lightroom or Camera Raw. This example is very close to the sepia/selenium-toned prints I used to produce. Figure 4.58 shows the original color image of some trimmed flowers I photographed with a Phase One 645FD camera with a P65+ back and a 120mm macro lens. It was shot at the Reykjavík botanical gardens in Iceland in between rain showers. The black-and-white conversion is also shown in Figure 4.58.

04_58.jpg

04_icon.jpg THE COLOR IMAGE

Figure 4.58

04_icon.jpg THE BLACK-AND-WHITE CONVERSION WITH THE FOLLOWING SETTINGS: –50 YELLOW AND –20 GREEN IN THE B&W PANEL MIX

Figure 4.58. The color image and black-and-white conversion with the custom B&W mix.

04_59.jpg

04_icon.jpg WARM TONING WITH A HUE OF 52 AND A SATURATION OF 25

Figure 4.59

04_icon.jpg COOL TONING WITH A HUE OF 236 AND A SATURATION OF 25

Figure 4.59. The warm and cool Split Toning adjustments.

Figure 4.60

Figure 4.60. The final result from the Split Toning panel adjustment in Lightroom or Camera Raw.

I wanted to darken the yellows in the image a lot (remember, green is mostly yellow), as well as darken the actual green color. As a neutral black-and-white image, I like it, but I wanted to push it a bit by adding a warm color to the highlights and a cooler color to the shadows to achieve a split-toned effect. Figure 4.59 shows the warm toning and the cool toning separately.

When the two color tints were combined, the result produced a split-toned image that looked a lot like a sepia/selenium-toned silver print. For the final image, I changed the Balance slider to –20 to keep some of the warm tint out of the deeper midtones. Figure 4.60 shows the final split-toned effect.

Cold toning and spot of color

This example is actually a two-for-one deal; it shows not only cold toning the shadows but also locally converting to black and white while preserving a portion of the image as color. For this image of a matador before a bullfight in San Miguel de Allende, I decided to locally convert to black and white using the Adjustment Brush set to a –100 Saturation setting. This allowed me to keep the red door and convert everything else to grayscale. You don’t have to convert to black and white in the HSL/Color/B&W panel—there are other ways to skin a cat. Figure 4.61 shows the original color image and the Adjustment Brush mask created using the Auto Mask and the resulting conversion retaining the red door.

04_61.jpg

04_icon.jpg THE COLOR IMAGE

04_61a.jpg

04_icon.jpg THE IMAGE WITH THE AUTO MASK CREATED

Figure 4.61

04_icon.jpg THE IMAGE CONVERTED TO BLACK AND WHITE USING DESATURATE AS A LOCAL ADJUSTMENT

Figure 4.61. The original color image, the mask showing the desaturated areas, and the final black-and-white conversion.

To bring up the detail in the horses, I used a plus Exposure (+0.80) and a plus Shadows (+96) adjustment, as well as a plus Clarity (+60) in the Basic panel to bring out the shadow detail missing on the original color image. I liked the red door in the black-and-white converted image but thought the heat of the red needed a colder color to offset it. For the final Split Toning settings, I used a Hue of 228 and a Saturation of 43 to get the cold look I wanted. Figure 4.62 shows the final result.

Figure 4.62

Figure 4.62. The final result of local black-and-white conversion and a cold tone for the shadows.

Optimized black-and-white tone mapping

Simply converting a color image to black and white and adjusting the black-and-white color mix won’t always produce an optimized black-and-white conversion. Often, you’ll need to optimize the tone mapping to get a dramatic black-and-white image. This example of some sand dollars shot at a roadside attraction in the Florida Keys is just such an image. Figure 4.63 shows the original color image at defaults.

Figure 4.63

Figure 4.63. The original color image of sand dollars.

The original color image was properly exposed—no clipping in Process Version 2012. I didn’t like the variation in the color of certain tonal regions, so I decided to convert to black and white pretty early after a global tone-mapping adjustment. Figure 4.64 shows the tone-mapped color image and the conversion to black and white with the default zeroed black-and-white conversion in the HSL/Color/B&W panel.

04_64.jpg

04_icon.jpg THE COLOR IMAGE TONED WITH THE FOLLOWING BASIC PANEL ADJUSTMENTS: EXPOSURE –0.65, CONTRAST +67, HIGHLIGHTS –100, SHADOWS +18, WHITES +29, BLACKS –6, AND CLARITY +100

Figure 4.64

04_icon.jpg THE DEFAULT ZEROED BLACK-AND-WHITE CONVERSION

Figure 4.64. The toned color image and the conversion to black and white.

I wanted to darken the image, increase the contrast, and really darken the highlights, while lightening the Shadows a bit and the Whites a bit more. Reducing Blacks helped pin the deepest tones to black. Changing Clarity to +100 was a strong move, but I’ve found that such strong tonal moves can work very well when converting to black and white. The color version of the image suffers, but the black-and-white conversion is improved. The converted black-and-white image looks better after the Basic panel tone mapping, but the image still needs curves work to extract the proper amount of tonality (at least from my point of view). Instead of trying to finesse the Tone Curve using the Point Curve Editor, I resorted to the Parametric Curve Editor to massage the final Tone Curve.

Figure 4.65 shows the final image with the Parametric Curve Editor edits applied. You’ll notice the nature of the curve—a sort of zigzag where Highlights are lightened while Lights are darkened. This is to more finely tune the ¼ tone areas and bring out the texture. The ¾ tone area also has been zigzagged by darkening the Darks a bit but substantially darkening the Shadows. All the adjustments were done by eye, based on what I wanted from the final Tone Curve.

Figure 4.65

Figure 4.65. The final tone-mapped black-and-white conversion.

Color toning using color curves

The San Miguel Chapel in Santa Fe, New Mexico, is reputed to be the oldest church in the United States. It was reportedly built between 1610 and 1626, but rebuilt in 1710 because of damage. It’s a U.S. National Historic Landmark that still has a Sunday Mass.

This example shows a nontraditional approach of color to black-and-white conversion and colorizing not by using the Split Toning panel but by using the per-channel color curves function of the Tone Curve panel. The original color image and the black-and-white conversion made by desaturating with a –100 Saturation adjustment in the Basic panel is shown in Figure 4.66. This black-and-white conversion also included an Adjustment Brush correction to substantially lighten the belfry to bring out the detail.

04_66.jpg

04_icon.jpg THE ORIGINAL COLOR IMAGE

Figure 4.66

Figure 4.66. The original color image and the adjusted black-and-white conversion, including local tone corrections.

THE BLACK-AND-WHITE CONVERSION USING A –100 SATURATION ADJUSTMENT IN THE BASIC PANEL AND THE LOCAL ADJUSTMENT BRUSH TO LIGHTEN THE BELFRY: EXPOSURE +1.84, CONTRAST 29, HIGHLIGHTS 55, SHADOWS 29, AND CLARITY 44

Instead of trying to adjust the color using the Split Toning panel, I used the per-channel adjustments in the Point Curve Editor of the Tone Curve panel. I added a plus Yellow and Red ¼ Tone Curve while adjusting the ¾ tones to be plus Blue and plus Cyan. Figure 4.67 shows the Red and Blue channel adjustments.

04_67.jpg

04_icon.jpg RED CHANNEL ¼ TONE POINT

04_67a.jpg

04_icon.jpg RED CHANNEL ¾ TONE POINT

04_67b.jpg

04_icon.jpg BLUE CHANNEL ¼ TONE POINT

04_67c.jpg

Figure 4.67 BLUE CHANNEL ¾ TONE POINT

Figure 4.67. Adjusting the Red and Blue channels.

The final image is a more graphic, nonrepresentational rendering of the church. Although it isn’t suitable for a lot of images, in this case, the strong graphic color works (at least for me). You can adjust the color in a more precise manner using color curves rather than the Split Toning panel. Figure 4.68 shows the final color curve-toned result.

Figure 4.68

Figure 4.68. The final color curve-toned black-and-white conversion.

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