To convert a color picture to shades of gray (a black-and-white photo), use this function. You can influence the method used, to guarantee perfect grayscale pictures with good contrast.
Some color contrasts will disappear after conversion to grayscale (e.g. the difference between green and blue or red), making the result look especially “gray” compared to a color picture. An elegant solution to this is color-channel-based grayscale conversion, which can give you a picture with good contrasts even in cases like this.
To use this function, go to Edit | Effects | Grayscale [Ctrl+G] in a Browser window, or Effects | Grayscale in an Editor window. This window offers you several methods for converting to grayscale. They affect how the individual color channels will be processed:
- Grayscale—uses all channels in a fixed ratio that corresponds to the typical way that the human eye perceives light. This is a useful method for most photographs.
- Desaturation—this removes the color elements from the picture.
- Advanced—this uses a complicated conversion method. The results are comparable with the first method, but more demanding on your computer.
- Average of channels—the average value among all color channels is calculated for each pixel.
- Maximum of channels—this uses the color channel with the highest value.
- Minimum of channels—this uses the color channel with the lowest value.
- Red channel—this uses the red channel only.
- Green channel—this uses the green channel only.
- Blue channel—this uses the blue channel only.
- Custom—the channels are used in the ratio that you set under Source channels. This method gives the most opportunity to choose which elements should receive how much emphasis. Turning on Normalize will ensure that the sum of the percentages will be an even 100%.