One stubborn dirt removal

After the printing plate was printed on the machine, the operator found that the printed product had just been printed, and there was a piece of oil-like scum on the background. Since the printing plate is baked, the stain is floating on the background color, so it cannot be treated with a hard object such as a blade or an etching rod, and it can only be removed by rubbing.

First wipe with a wool cloth wet wipe powder a few times, after the boot still appears dirty. Then use a wool cloth to wipe it with phosphoric acid, or you can't remove it. It was wiped with a piece of cloth, gasoline, water, and a dampening powder, and it was rubbed with a finger instead of a cloth. It was still impossible to remove this stubborn stain. It is useless to find a clean paste and continue to wipe it with a cloth. Also wipe with a finger to repair the paste, or according to the dirty. How can we remove it without causing it to be scrapped? Considering that the dirty mark appeared when printing on the machine, the operator estimates that it is likely that the printing process has not been processed properly. Can it be removed with the developer? When the developer cloth is still wiped with the developer cloth, the dirt on the plate is still clearly visible, but the dirt on the print is gone. It can be seen that the developer is very effective for removing some stubborn stains on the printing plate after being put on the machine.

(Shandong People's Printing Factory Miao Yinkai)

Source: "Printing Technology - Publishing Commercial Printing"