Black and white photography is the original; classic, striking, moody, and reduces the photo to a more fundamental state. It is one of my favorite forms of photography and from some of the most famous photographers, there is nothing quite like it. Ansel Adams, Mary Ellen Mark, Yusuf Karsh, amount many others, are renown for their use of black and white.
In today's digital world, there are very few actual black and white cameras; the Leica Monochrom, Red Epic-M Dragon (monochrome) are a few notable examples that come to mind but, generally, if you're using a digital camera, even with a black and white mode, you're shooting color (RGB — red, green, blue) and it is converted to black and white. In other words, if you're making or seeing black and white digital photography, chances are you're look it was originally color.
Without giving a long scientific explanation of why or how digital cameras work, a "general" digital camera have a sensor with pixels, each capturing its own color: red, green, or blue. The Leica M Monochrom uses a sensor where each pixel captures only luminance.
Many of us simply can't afford a Leica or we would really like the option of color photography. Sadly, we can't, or currently can't, have a camera that is "dual-action" color or mono. As such, we'll need to settle for one or the other but don't be discouraged, a color photo can be altered into a stunning black and white photography.
In OS X's Photos app, there are three filters for use to convert your images: Mono, Tonal, and Noir (my personal favorite). Having covered how to use filters in a previous post, we'll forego these and move into a more advanced technique for black and white conversions and more flexible.
Opening an image and entering the edit mode, one will click on Adjustments. Even with the default option for adjustments, black and white is a already visible. Using the adjustment is a simple using the slider until the desired black and white appearance is achieved. This adjustment mimics the effects of using a color filter on black and white film.
This alone will give you more flexibility than just the general black and white filters. However, opening the adjustments will bring more control and a finer look should the basic black and white slider.
Upon opening Black & White, four additional sliders are available: Intensity, Neutrals, Tone, and Grain.
These adjustments are the key to taking advantage of the black and white capabilities of Photos. While it is a simple toolset, there is a great amount of flexibility, like nothing found in iPhoto, and also found on the iOS version of Photos. It is far different from yours average black and white conversion tool found in other apps, I have come to enjoy the ease and power.
Intensity: The strength by which the effect is applied to the photo.
Neutrals: Lightens or darkens the gray areas (midtones) of the photo.
Tone: Adjusts the photo for a more high-contrast or low-contrast look.
Grain: Adjusts the amount of film grain that appears in the photo.
For the final version of Art Deco Mountain, I initially expected I would use the Noir built-in filter, however, I found it too intense. While I wanted a nearly black sky with high contract with the highlights, the shadow area of the building was too dark. Applying the Black & White adjustment and fine tuning the Intensity, Neutrals, and Tone, the sky looked as I wished as did the building.
Making good use of these four adjustments on can achieve many high quality black and white effects on a photograph. This is to say, we should not forget about the many other adjustments available in Photos as things like Color, Contrast, Definition, and many others will also impact your black and white photography.