Photography Photoshop

How to Convert a Color Photo into BW Using Channels

I’ve been busy off the grid for a couple weeks. Last week I spoke at Create Without Limits, an invitation only event for corporate executives where we discussed ideas about how art and business collide and synthesize. Two weeks ago I ran a workshop for emerging hobbyists in Bangkok, and promised the participants a short tutorial on how to convert a photo to black and white.

I chose to teach a BW conversion using Channels because it seems to me to be the easiest, apart from just using the Black and White automatic conversion on PS4 and PS5 (which is pretty good, and very easy). The workshop students also needed to practice using layers, so the Channels conversion was a good way to do this.

Step 1. The first thing is to start with the original file, and adjust Levels.

Adjusting levels using the dropper tools.

Step 2. Use the black dropper tool to choose a black point. Set the dropper over the darkest part of the photo, and click once.

Adjusting black point for levels.

Step 3. Choose the white point by clicking on the white dropper tool, then clicking on the whitest point in the photo.

Choose a white point to adjust levels.

Step 4. Choose the gray point. I chose a section of the man’s hair, that I saw was halfway between my blacks and whites.

Choose an area that is halfway between black and white for the gray point in levels adjustment.

Step 6. Now we’re ready to make the photo black and white. Make a new layer and name it “Channels.” Then click on each channel in the Channels menu to see which channel suits the subject’s tones. I chose the Green Channel for the man’s tones, and the Blue Channel for the shadows, because the Blue Channel’s shadows seemed richer, grittier, which is the look I want.

The Channels Menu is right beside the Layers Menu.
The Green Channel's tones looked great for the man.
The Blue Channel looked perfect for the background, to bring out rich blacks and grittiness.

Step 7. After picking these two channels for my subject and background, it’s time to blend the two layers. There’s a simple way of doing this. Put the layer that has the least change ABOVE the layer that has the most change. I moved the Blue Channel layer on top of the Green channel layer, so that I could just mask out the man.

Blending the two channel layers into one image using layers.

Step 8. To mask out the man, simply click on the Add Layer Mask button (it looks like a square with a circle in the middle) which is at the bottom of the Layers Menu on the right side of the screen. Then I take a soft brush at 100 percent opacity and brush the man so that the Green Channel layer for the man’s tones become blended with the Blue Channel layer, the background.

Tools for blending the layers: Layer Mask, Brush. Easy peasy!

Step 9. After blending the two channels layers, it’s time to refine the image. I found some spots on the background that were distracting in the photo. So I chose the Clone Tool, sampled areas close to the spots, and ran the Clone Tool over the distracting spots until the image looked cleaner.

So many distracting spots! They must be removed to give the image a neat finish.
The Clone Tool icon looks like a stamp.
After removing the spots, I merged the layers using this shortcut: Command + Option + Shift + E.

Step 10. Looking at the photo, I wanted more contrast between the black background and the lighter subject, so I decided to (1) use the Burn Tool to darken the shadows. (2) Don’t forget to name this layer “Burn!”

The Burn Tool helps to darken areas of the photo if you run it over that spot. I use no more than a 20 percent opacity.

Step 11. To sharpen the photo and add more contrast, I used the Unsharp Mask tool located under Filter>Sharpen>Unsharp Mask. A window pops up asking you to put in Amount, Radius, and Threshold. For Amount, I typed in 120. For Radius, I put in 1, and left the Threshold at 0. Then I clicked OK.

Sharpening using Unsharp Mask.

Step 12. Last step! I flattened the image (Layer>Flatten Image) and resized it for the web, and here it is.

The finished black and white image, ready in 12 easy steps.

It’s not that difficult to convert a color photo into a black and white image using Channels. Try it and see!

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