A great black and white portrait isn’t a color portrait with the saturation removed. It’s a fundamentally different interpretation of the image, and the conversion process gives you enormous creative control if you know how to use it.

Here’s why “just desaturate” is the worst way to convert, and what to do instead.

Why Desaturation Fails

When you desaturate an image (Image > Adjustments > Desaturate), Photoshop converts each pixel to a gray value based on a fixed luminosity formula. It doesn’t care about the relationships between colors. Red lips and green foliage might end up the exact same shade of gray, destroying the contrast that made the color image work.

Good black and white conversion is about controlling how each color translates to a gray value.

Method 1: Black & White Adjustment Layer

This is the most straightforward professional method.

  1. Add a Black & White adjustment layer (Layer > New Adjustment Layer > Black & White)
  2. You’ll see sliders for Reds, Yellows, Greens, Cyans, Blues, and Magentas
  3. Each slider controls how bright or dark that color becomes in the conversion

For portraits, start here:

  • Reds: 50-70 (this controls skin tone brightness — higher values give smoother, more flattering skin)
  • Yellows: 60-80 (also affects skin, especially warmer tones)
  • Blues: -20 to 20 (darkening blues can add drama to sky backgrounds)
  • Greens: Adjust based on whether there’s foliage in the image

The ability to adjust these independently is what makes this method powerful. You can brighten skin while darkening a blue background, creating separation that wouldn’t exist with simple desaturation.

Method 2: Channel Mixer

For more technical control, use the Channel Mixer.

  1. Add a Channel Mixer adjustment layer
  2. Check “Monochrome” at the bottom
  3. Adjust the Red, Green, and Blue percentages

The key rule: the three channels should add up to roughly 100% to maintain overall exposure. Going above 100% brightens the image; below darkens it.

Classic portrait formula: Red 60%, Green 30%, Blue 10%. This emphasizes the red channel, which typically renders skin the most smoothly because skin has strong red values.

The Retouching Sequence Matters

Here’s something many retouchers get wrong: when should you convert to black and white — before or after retouching?

Always retouch in color first, then convert. The reason is practical: color information helps you identify skin issues. Redness, uneven tones, and color casts are invisible in black and white but obvious in color. If you convert first, you’re retouching blind.

The one exception: dodge and burn. After your color conversion is applied, do a final pass of dodge and burn specifically for the black and white version. The tonal relationships change during conversion, and areas that looked perfectly sculpted in color might need adjustment.

Adding Grain

Many of the most striking black and white portraits have visible grain. It adds a film-like quality and masks minor skin texture imperfections.

  1. Create a new layer filled with 50% gray
  2. Set the blend mode to Overlay
  3. Add noise: Filter > Noise > Add Noise (Gaussian, Monochromatic, 3-8%)
  4. Optionally blur slightly: Filter > Blur > Gaussian Blur at 0.3-0.5 pixels

The slight blur on the grain prevents it from looking digital. Real film grain has soft edges, not hard pixel noise.

Final Tip: Print Your Black and White Work

Black and white portraits look dramatically better in print than on screen. If you’re doing serious black and white work, invest in a few test prints. The tonal range, depth, and texture of a well-printed black and white portrait is something a monitor simply cannot reproduce.