For maximum visibility, what is the minimum transparency letting that should be used?

The minimum transparency letting, which refers to the spacing between lines of text, is crucial for ensuring that written materials are easily readable, especially in contexts where clarity is essential, such as in instruction manuals or educational materials used in esthetics. In this scenario, using 18 point typeface represents a balance between visibility and readability, making it the appropriate choice for maximum visibility. This point size allows for ample spacing between lines, reducing crowding and helping to cater to individuals who may have visual impairments or difficulties in reading smaller text.

Using a larger typeface, such as 24 points, may improve visibility further, but it can also take up more space and potentially lead to less information being conveyed on a page. On the other hand, typefaces smaller than 18 points, like 12 or 14 points, generally do not provide the same level of readability, particularly from a distance or in poor lighting conditions. Therefore, 18 point typeface is identified as the minimum size for ensuring clarity and maximum visibility in instructional texts for esthetics.