In this case the recommendation is to include a short summary in the ALT tag which points to or links blind users to a long text description which fully explains the image. In most cases, the long description should be available to all users. This long description will not only assist blind users but also sighted users who may not understand a complex image. The examples below will provide examples of long description and how to place them to benefit the most users. Example Technical Illustration
Below is a diagram of fluid laminar flow in a circular pipe. The velocity profile is parabolic indicating that flow velocity at the walls is slower than in the center. Velocity profile of laminar flow in a pipe
ALT = "Velocity profile of laminar flow in a pipe." Long Description Used
This diagram shows fluid flowing through a pipe along the x-axis in parallel layers with minimal disruption. Velocity arrows are shorter on the edges, representing a slower velocity vx and longer in the center, representing a faster. The edges of the arrow form a parabola and represent the "velocity profile."
