The JoJo manga is mainly in black and white. Colored versions exist but are not the norm. Sometimes, colored illustrations are done for promotional purposes or by fans.
The Bleach manga is not colored. It's common for manga to be in black and white to focus on the line art and storytelling. Color versions might exist in certain promotions or adaptations, but the core manga is monochrome.
Comics are often colored using digital software or traditional mediums like paints and markers. It depends on the artist's preference and the style they want to achieve.
Generally, manga are black and white. This is mainly due to cost and production time constraints. However, some popular series might have colored pages for special chapters or volumes.
You can search for colored manga on specialized manga websites or platforms. Some artists or groups might upload colored versions of popular manga there.
Newspaper comics are often colored using digital tools or traditional methods like watercolors or colored pencils. The choice depends on the artist's preference and the requirements of the publication.