Convert PDF four colors (CMYK) black to 100% black.

Converting 4-color cmyk fonts to 100% black
When to use it?
If the PDF contains 4 color cmyk black letters and graphics. These letters or graphics will not be sharp or contoured when printed.
This conversion does not apply to the letters in the photos
What part of PDF is affected by it?
When converting, CMYK black letters and graphics are converted to 100% black.
What to watch for?
Conversion occurs only when cyan, magenta, and yellow are greater than 50% and black is greater than 60%.
Conversion: cyan: 51%, magenta: 51%, yellow: 51%, black 61%.
No conversion: cyan: 51%, magenta: 51%, yellow: 48%, black 71%.
1. Font as font in the PDF.
2. Letter as image in PDF.
3. Four-color cmyk font.
4. Four-color cmyk font for each color.
5. Result is 100% black.
font as font
font as image
cmyk four-color font
cmyk four-color font in the PDF
100 % black font
How to use it?