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Converting a Color Image
to Black and White
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There are many ways to convert a color image to black and white,
also known as grayscale.

Original Imagte
  
Original Image CP

Original Color Images

Greyscale

Greyscap COnversion CP

Change Image Mode to Grayscale
Photoshop makes all the decisions about how much brightness from each color to include. it is intended to work well for the average picture.

On the Image menu select Mode and then Grayscale. This method does not allow you to retain the color information.

Desaturate

Desaturate CP

Desaturate
Photoshop adds the numeric values of the RGB channels and divides by three to determine the brightness of each pixel.

In order to retain the color information for future use, add a Hue and Saturation adjustment layer and move the saturation slider to all the way to 0.

Experiment by dropping down the list at the top and changing it from Master to a color and then desaturating. You can also partial desaturate.

Channel Mixer

Channcel Mixer B&W 1 Channel Mixer B&W 2 Channel Mixer B&W CP 3

The Channel Mixer
You can select how much brightness from each channel channel (RGB) is included.

In order to retain the color information for future use, add a Channel Mixer adjustment layer.

  1. Make sure the Monochrome and Preview boxes are checked.
  2. Move the sliders for each channel to determine how much information from each channel you want to include.
  3. The total of the three channels should be around 100%.

If the total is much higher than 100% the image will lose a lot of detail in the highlights.

If the total is much lower than 100% the image will lose a lot of detail in the shadows.

To simulate infra red photography, try raising Red up to 200%, lowering Blue to -200% and raising Green up to about 100%. Adjust from there.

CHanncel Mixer convesion to B&W with faux IR

Lab Conversion

LAB COnversion to B&W CP

LAB Conversion
This method uses the LAB color space that is built in to Photoshop to do the conversion.

  1. Convert image mode to LAB color/
  2. In the channels palette, highlight the lightness channel, L.
  3. Convert the image mode to Grayscale. You will be asked if it is OK to discard the other layers, say OK.
  4. Ctrl-Click the L image to load it as a selection and invert the selection.
  5. Convert mode to RGB
  6. Add a Color Fill Layer. Pick a neutral color, like a dark gray.
  7. Set the blending mode of the adjustment layer to Multiply. Try experimenting with other blending modes.
  8. After this you can add a Levels or Curves adjustment layer for more control. Or try changing the opacity of the fill layer.

By modifying the color of the fill layer you can change the color of the resulting image.

LAB with Sepia Tone

LAB Conversion to B&W CP w green tone

 

© Copyright Laura Balsam 2004 - 2005