Post-processing a Black and White Photograph

Post-processing a Black and White Photograph

Estimated reading time: 27 minutes

Post-processing with Adobe ® Lightroom – The Develop Module

Last month, we looked at the Radial Filter Tool, the last Local Adjustment Tools we needed to explore.
Today we will explore how to combine all three tools while improving a Black and White photograph. However, before we start with the practical exercise, we’ll look at some theoretical information that will help us understand the reasons behind our changes.

What is a Black and White photograph?

A Black and White photograph is a greyscale representation of a color image. Sounds easy enough. However, what does that mean?

The combination of three different information types creates a color. These information types are:

  1. The Tone or Hue of the color (red, green, purple).
  2. The Saturation of the color.
  3. The Luminance of the color.

In the figure below, you can see the base colors of the RGB and CMYK color schemes.

Colors of the RGB and CMYK color schemes - basic knowledge for post-processing images
Colors of the RGB and CMYK color schemes

A Black and White image does not contain any color saturation or hue; It only consists of luminance values, ranging from the deepest black to the brightest white.
So let us remove the tone and Saturation from the colors above, to create a greyscale of these.

Greyscale of the RGB and CMYK color scheme
Greyscale of the RGB and CMYK color schemes

If you look closely at the greyscale, you will notice that the fourth and seventh grey tones are pretty close. Whereas, if I add the color scale next to it from which I created the greyscale, you will easily spot the different colors.

Comparing the color and greyscale version of the RGB and CMYK color scale
Greyscale and color version of the RGB and CMYK schemes side by side

Why is that a problem?

If you were to create a painting in grey tones, this would not be a problem, as you would choose which grey tones to place next to each other. However, when you convert a photograph from color to Black and White, you might end up with dark green foliage having the same grey tone as the sky. As a result, your image is going to look flat.

Let us have a look at an example to visualize the problem.

Color photo of the Troyan Monastery after post-processing
Color photo after post processing of the Troyan Monastery
Black and White conversion without using any local adjustments of the greys
Direct Black and White Conversion of the photo above

If you compare the two photos above, the color version will have a stronger message, while the Black and White lacks impact. However, with some clever post-processing, we can improve the Black and White photo a lot.

The Zone System

Now that we have had a brief look into what might go wrong when simply converting a color photo to black and white, let’s look at a tool to help us improve our photographs.

In the 1940s, Fred Robert Archer(1889, †1963) and Ansel Adams (1902, †1984) developed a zone system. This system aims to improve your chances of exposing your photograph correctly. It was, after all, developed in the days of analog film photography, where results weren’t viewable before long after the photographer took the shot. However, you can apply the same system to post-processing. Ansel Adams left his printer with detailed notes on how to use the zones for the prints of the photographs.

The zone system is a scale consisting out of 9 grey tones plus pure black and pure white. Each of these is one-stop apart from the next one. They get numbered from 0 for pure black to X for pure white.

Ansel Adams' and Fred Robert Archer's Zone System to help with image exposure and post-processing
The Zone System developed by Ansel Adams and Fred Robert Archer

Using the Zone System while taking a photograph

Zone V is the luminosity your camera is measuring against. So if you were to photograph a snow landscape under a bright blue sky, set your measuring to spot measuring, and then used the automatic to determine the Exposure, this is the tone your camera assumes the snow should be. On the other hand, if you were to photograph something rather dark, say a black wall, your camera would think that the black wall had this tone of grey found in zone V.

By using the zone system, you know what your camera assumes, and you can then correct these values. For example, say for that snow landscape, you want the snow to be white, but not so white that it loses all the detail. So you use exposure compensation to expose not in zone V but maybe in zone VII, which means that you have to dial in a value of EV +2.

Here, the zone system helps you to get the correct Exposure without looking at the histogram.

How to use the Zone System in post-processing

With a color image, you have a range of tools to improve your composition. Some of them also exist in monochrome photography, like leading lines or the rule of thirds. However, you won’t have a chance to use the Saturation or tonality of color to emphasize your subject. And yet, in most cases, you would like to see the difference between the blue sky and the green foliage, for example. In monochrome photography, you use different luminosities to separate the two from each other. So you could, for example, decide to use a lighter grey tone for the sky and a darker grey for the foliage.

The zone system can help you with more, though. The bright areas in an image always attract the viewer’s eye. As an image creator, you do not want the brightest part of your picture to be in the foreground because that would stop the viewer from exploring the entire frame. If you, however, place darker elements in the foreground and then stack lighter elements toward the background, you will lead the viewer through your image. If you can combine that with a leading line, like a road or a river, you will create a much stronger impression.

Preparations

Before you can successfully post-process any photo, you should calibrate your screen. Your uncalibrated screen, even if it comes right out of the box, might have a color cast to it that you won’t notice right away. However, if you then start post-processing a landscape, reducing a non-existing green tint (which you see because your screen has it, not your photograph), you end up with an image with a magenta tint in print.
Usually, screens out of the box are also too bright, making them appear to have better contrast.

In the following figure, I created a grayscale ranging from pure black to pure white, with 16 different shades of grey in between them. If you can distinguish all these squares from each other, you most likely have a well-lit screen.

16 shades of grey - can you see the differences between all of them?
16 shades of grey

Screen Calibration

Both for Mac and Windows, there are operating system tools to help you calibrate your screen. However, in most cases, you will not get reliable colors, and worse, your results won’t be repeatable in the future. Errors will occur because the light in your room is different from the first time and most likely never being at a color temperature of 5000K, which makes it hard, if not impossible, for your eyes to evaluate your screen’s colors. So if you can afford it and want the best possible results, there is no better time than before you start post-processing to get into screen calibration.

However, if you go for the investment, you would like to double-check that your computer supports these devices and their measurements. Especially if you are on a laptop, I read some time ago that some Laptop manufacturers do not support screen calibration. Unfortunately, I cannot remember who that was. So you want to make sure about that first.

With monochrome photography, the most important thing to get correct is the brightness settings, of course. How will you determine the 11 zones of the zone system if you can only distinguish fewer than 10?
Latest, when you want to start printing your work by a professional laboratory, there is no way around propper screen calibration. Rapefields are not mustard-colored, and I speak from my own experience, of course 😉

Creating a Black and White image in Adobe ® Lightroom

Let us put all that we have learned about the Local Adjustment Tools into practice and create a stunning Black and White representation of the color image below.

Color photo after post-processing
Color photo after post processing of the Troyan Monastery

First, we have to convert this image to Black and White before we make all the adjustments. For this, we select Black and White in the Treatment section of the Basic Panel of Adobe ® Lightroom’s Develop Module. It is circled in red in the figure below.

Lightroom Treatment option in the Basic Panel
Treatment Black & White

This single click converts your color image into an appropriate Black and White photograph.
You could have used the saturation slider and moved that to the -100 setting. However, that comes with the disadvantage that you can no longer adjust the Luminosity of the different color channels. As we have seen above, the representation of a green and blue color, for example, converted into black and white, can result in a very similar shade of grey. Using the Black and White Treatment instead leaves the option to change the Luminosity of different color channels.
The following figure shows the result of the Treatment change.

Black and White conversion of the color photo without any adjustments
Direct Black and White Conversion of the photo above

The idea

The pure Black and White conversion leads to a nice but not a very dramatic image.
I want to create a photograph where the tower in the background becomes the main focal point of the image. I will work with Color Channel Adjustments to darken the sky and the brick walls before I start using Adjustment Brushes to darken the three marked areas in the figure below.

Areas in the black and white where we are going to use Local Adjustment brushes to improve the photograph
Areas where we are going to use the Brush Tool later on

Finally, I will use Graduated Filters on the sky and the ground to emphasize the tower.
Let’s get started.

Color Channel Adjustments

Since the sky’s blue and the stone’s yellow coloring are in parts translated into similar shades of grey, I decided in a first step to darken the blues.
In the new B&W Panel of the Develop Module, replacing the HSL/Color Panel for color images, I am dragging the Blue slider to -100 and the Purple slider to -18. The B&W Panel only becomes available if you select Black & White as a treatment option or select one of the Monochrome Profiles.

Color channel settings for the blue channel
Blue Level Adjustments

This small change affects my photograph significantly. Let’s have a look.

Photo after the blue channel is adjusted
Troyan Monastery with blue levels adjusted

I assume you can spot the difference between this version and the previous one immediately. However, I want more.

To separate the tall tree on the upper left from the clouds and darken the brick walls, I am changing the Yellow and Orange Color channel to darker tones.

Adjustment settings for the yellow channel
Yellow Level Adjustment Settings

I opt for a less radical change this time than when I changed the Blue and Violett channel. I am only setting the Yellow slider to -32 and the Orange one to -23. However, these more minor adjustments already have some effect on my photograph.

Photo after the yellow and blue channels are adjusted
The monastery after a blue and yellow level adjustment

Now it is time to move from Global Adjustments to Local Adjustments to target specific areas in the photo.

Using the Adjustment Brushes as Local Adjustments

In a Black and White image, the brightness of the tones is leading the eye toward the photograph’s subject. Your vision will follow a path from darker tones to the brightest tones, and if you have placed these sufficiently, rest there. Leading lines, however subtle, can enhance or break the effect. Therefore, I have decided to darken the church itself and the building in the left foreground, leaving the tower as the brightest part of the image.

Targeting the church building with an Adjustment Brush

With my first Adjustment Brush, I will darken the church building. So I am painting the church with the Adjustment Brush, fine-tuning where I paint with a small Erase Brush on the go. It does not have to be super precise. However, it helps if you do not go excessively over the borders of the church.

Target area for the first Adjustment Brush marked in red
Brush target area marked

The figure above shows which areas (red) I have selected as target areas for my first local adjustment.

Settings of the first adjustment brush
Brush Settings

By setting the Exposure to -0.7, I am darkening the church building just a little more, but not so much that the viewer can no longer see its details.

Photo after darkening the church building
Church Building darkened with the Adjustment Brush

As you can see above, the church building is now significantly darker than before.

Applying a second Adjustment Brush on the brick wall

My next step is to darken the brick wall, roof, and tree foliage on the left side of the image. Again I am opting for an Adjustment Brush to select the areas I want to address.

The figure below shows you exactly which areas I am going to change with this second brush.

Target area for the second Adjustment Brush
Target area for the second Local Adjustment

I have again chosen to correct minor errors in my brushing using an Erase Brush. If the luminance values weren’t as close to each other as they are, I might have opted for a Luminance Mask with the Range Mask tool of the Adjustment Brush. However, its effect was not quite what I had in mind.

My settings for this second brush are Exposure -0.92 and +32 for the Texture, as shown in the figure below.

Settings for the second Local Adjustment Brush
Settings for the second Local Adjustment Brush
Results after also darkening the brisk wall on the left
Results after darkening the brick wall and roof with an Adjustment Brush

The result is not bad; however, I find the white building on the left side is competing too much with my main subject. So let’s address that with a third Adjustment Brush.

Using a third and final Adjustment Brush to adjust the white wall

I am, again, using an Adjustment Brush to target the white building. Since there are some darker wooden structures within the wall, I use the Erase Brush to fine-tune where I place the adjustment.
The following figure shows my selection.

Targeting the white building on the left side
Targeting the white building

I want to darken the white wall. However, I don’t want it to look like a grey wall. Therefore I am setting the brush’s exposure correction only to -0.64.

Settings for the Third and final brush
Settings for the third Adjustment Brush

The result is a decent Black and White image like in the figure below.

Monastery after applying the third Adjustment Brush
Monastery after applying a third local Adjustment Brush

However, I still want more.

Using more Local Adjustments: Graduated Filters

To put even more emphasis on the church tower and bind the entire image together, I use three graduated filters. First, I will use two graduated filters on the sky. A bigger Graduated Filter goes down to about the top of the church’s roof, and a smaller one addresses only the topmost part of the sky.

First Graduated Filter for the Sky

I want to darken the sky so that the image gets a more dramatic effect.
The first filter covers the area down to the church building’s rooftop, as shown in the following figure.

Target area for the first Graduated Filter in the sky
First Graduated Filter

I don’t want to darken the sky so much that it becomes unrealistic. So I am setting the Exposure value of this filter to -0.64, as shown below.

Graduated Filter Settings
Settings for the first Graduated Filter

The effect of this filter is visible in the image below.

Image after we applied the first Graduated Filter
Image after applying the first Graduated Filter

Second Graduated Filter for the Sky

The second Graduated Filter is a lot slimmer than the first one. This width difference means it almost reassembles a Hard Grad filter, where you can see the border between the darkened and the unaffected area. I am using it only for the top of the sky so that the cloudless section gets even darker.

Target area for the second graduated Filter - Using Local Adjustments to post-process a Black and White image
Area that the second Graduated Filter covers marked in red

However, I won’t make drastic adjustments. A slight change of the Exposure to -0.64 is enough to have a significant effect on the image.

Settings for the second Graduated Filter
Settings of the second Graduated Filter

The photograph now looks like in the following figure.

Monastery with the second Graduated Filter applied - Using Local Adjustments to post-process a Black and White image
Monastery with the second Graduated Filter applied

Third and final Graduated Filter for the ground

To bind all my changes together and emphasize the leading line effect of the path going toward the church tower, I am adding a third Graduated Filter. This time it will reach from the bottom of the image to the lower part of the church tower’s wall, as depicted in the figure below.

Target area for the third graduated Filter on the ground
Area affected by the third Graduated Filter

Again, I am only making subtle changes to the Exposure, setting it to a value of -0.64.

Settings for the third graduated filter - Using Local Adjustments to post-process a Black and White image
Settings of the third Graduated Filter

Now I am satisfied with the outcome of all my changes to the image.

Final Black and White after using Local Adjustments in the post-processing
Final image after applying the third Graduated Filter
Where we started with the simple black and white conversion before using any local adjustments
Our starting point after selecting the Black and White Treatment

Fazit

Over the course of this article, we had a brief look into the fundamentals of Black and White processing and screen calibrations. We finished it by processing a photo from its color edition into a stunning Black and White image. We achieved some significant effects with subtle changes using Adjustment Brushes and Graduated Filters.

If you compare it to the Black and White image that we started with, which one do you like better? Is there any step along the course of the post-processing where you think we should have stopped and called it a final piece of art, or would you go all the way as well?





All trademarks and copyrighted items mentioned are the property of their respective owners.

I am in no way affiliated with any of the products used in this post-processing process. I do not receive any kind of compensation for this article, it was neither offered or asked for.

THIS BLOG ARTICLE “Welcome to September 2021″ IS NOT AUTHORIZED, ENDORSED OR SPONSORED BY ADOBE SYSTEMS INCORPORATED, PUBLISHER OF ADOBE ® LIGHTROOM

All photos taken by Lille Ulven Photography/Wiebke Schröder.

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