There will be some differences between the colors displayed on the computer and those printed, but there should be little difference between the colors seen in photoshop. Generally, the printed color is darker than that seen in PS.

Black can be K 100 C30. The minimum font size is not clear, and it seems that small characters can be printed generally. Besides, your printed words are too small for others to read clearly. When printing, it should be noted that the words should not be too close to the edge, and there should be a bleeding size of about 3mm next to them. If the print is all black and sent to the printing factory, people will definitely let you change it. Generally, the printing factory will not print all four colors in black, which is harmful to the machine. Last year, people printed recipes for us, most of which were black, and as a result, all their machines were printed out. If you are afraid of blue, you can only use monochrome black. But I can't seem to see any blue when I print with K 100C30.