mogrify -level 2080 input.jpg -type grayscale output.jpg
This command will convert the input image to grayscale and then adjust the contrast so that everything becomes pure black and white. The `2080` value represents the luminosity level, with higher values resulting in a higher contrast image.
Alternatively, you can use the `convert` command instead of `mogrify`, it will give you the same result.
convert input.jpg -level 2080 output.jpg
If you want to convert an image of a document into a high contrast black and white PDF, you can use Adobe Acrobat. To do this, open the image in Adobe Acrobat and click on the Print button in the toolbar. Select Microsoft Print to PDF as the printer and tick the Print in grayscale (black and white) option. Then, click Save as PDF and choose a name for the file.
Another option is to use a free online tool such as PDF Tools, which allows you to convert color PDFs to black and white grayscale. Simply upload the PDF document and click the Convert button to get a high contrast black and white version of the document.
If you want to increase the contrast of a PDF that was created from a colored image, you can use ImageMagick's `mogrify` command to adjust the contrast of each page individually. For example:
mogrify -level 2080 input.pdf -type grayscale output.pdf
This command will convert each page of the input PDF to grayscale and then adjust the contrast so that everything becomes pure black and white.
I hope this helps! Let me know if you have any other questions.