Monochrome conversion
Contents
When you export an image you may also choose to convert its colors to 'black and white' or 'gray scale' in the output document.
| 1. | Select Configuration from the 'Options' menu (function key f8) and click the Images tab or select Export from the 'File' menu (Ctrl E) – see Image format file export. Select an image format such as BMP or PNG then click the Image options... button. |
| 2. | Tick Force monochrome. |
| 3. | Choose a conversion method from the drop-down list of options: |
| o | Halftone (Default option) The image is treated as if it were composed of blocks of pixels (block size 4x4 pixels). The average luminosity of each block is matched to a shade of gray with similar luminosity. Gray shades are actually blocks of black dots on white – the number and pattern of the dots within each block determining its overall luminosity. |
| o | Threshold This assigns black pixels to colors with a luminosity below the threshold value, and white to the remainder. Enter a value in the range 1 to 254 (default value is 127, i.e. 50%). |
| o | Adaptive The density in each quadrant of the image is computed and the image adjusted by interpolating between these values. The image is then converted to a 1-bit image using the specified threshold value. |
| o | Dither A method of error diffusion that takes into account the discrepancy between the original luminosity of a pixel and the monochrome value that the default threshold value of 50% would assign to it. The difference is propagated to adjacent pixels, resulting in a more randomized scatter of black and white pixels than basic thresholding. |
| o | Gray Converts image to solid gray-scale shades rather than black-and-white dot patterns; select also 4-bit or 8-bit Smoothing for output to Monochrome images. |
Links