To achieve "plain" impressions, how should all fingers be pressed?

To achieve "plain" impressions, pressing all fingers simultaneously is important because it allows for a uniform and complete impression of the fingerprint patterns on the designated surface. When fingers are pressed together at the same time, it can ensure that they are aligned properly and maintain consistent pressure, which is essential to capturing an accurate representation of the ridges and unique characteristics of each finger.

Simultaneous printing helps avoid distortion that can occur with other methods, such as sequential or individual presses, where slight variations in pressure or alignment can alter the quality of the fingerprint impressions. Achieving an even transfer of ink across all fingers can be crucial for subsequent identification and examination purposes, as inconsistencies might lead to misinterpretation or inadequate evidence.

In practical applications, such as criminal identification or biometric systems, the accuracy of fingerprint impressions is vital. Thus, pressing all fingers at once facilitates a clearer, more distinct set of impressions that reflect the true characteristics of the fingerprints, enhancing their usability in systems requiring such identification.