Scumming in offset lithography refers to a condition where non-image areas on the printing plate begin to attract ink. Consequently, unwanted spots or patches of ink are transferred onto the paper surface. This issue is typically caused by a failure of the fountain solution to function correctly, meaning the area intended to remain hydrophilic (water-loving) loses its ink-repelling properties. Understanding this phenomenon is critical for print operators as it allows them to diagnose the precise root cause of unwanted marks. If Scumming is left unchecked, this widespread contamination can quickly result in the spoilage of numerous print sheets and substantial material waste.