Why are some lines still colored when printing in PDF format using CAD and monochrome.ctb?

When you use monochrome.ctb to print a PDF in AutoCAD, all lines should theoretically be black. However, if some lines remain colored, this may be due to the following reasons: 1. You may have selected “Color” instead of “Black and White” in the printing settings. 2. In your drawing, some objects may already have colors assigned to them directly, rather than using the color of their layer. Such objects will retain their original colors when printed, unaffected by the .ctb file. 3. The .ctb file you are using may have been modified. Make sure you are using the original monochrome.ctb file, or check whether the settings of the .ctb file are correct. 4. Some special line styles, such as gradient fills or solid fills, may display colors when printed, even if you are using monochrome.ctb. If you have checked all of the above possibilities and everything seems fine, but the problem still persists, then there might be an issue with your AutoCAD software; you can consider updating or reinstalling it. .

In CAD, enable the feature for colored lines and check whether a different color has been set; change it to follow the layer color.

Isn’t it true that all line colors are set to black in the print style?