Flash Rust

Lighting and Angle of Light Source

Posted on 15. Mar, 2009 by charles frenzel in NSRP

Lighting and Angle of Light Source
Illumination is critical.
Use as a standard Reference Document SSPC Guide 12
“Guide for Illumination of Industrial Painting Projects”

The visual guides do not show the effect of the angle of the light source.

SSPC Technology Guide No. 12 recommends an illumination of 50 foot candles minimum to 200 foot candles for inspection. The foot-candle is equal to one lumen per ft². It is the amount of light that reaches the target surface.

From Todd Pacific in-house training:
 Illumination is a very important factor in making any quantitative evaluation. Low light conditions will prevent your ability to see…..and the chore is to determine if you can see clean steel through and along with the flash rust.
 The point here is to observe and determine if the steel substrate is or is NOT obscured by the quantity of flash rust.

Perception along a glancing angle is very different that making the observation perpendicular to the surface.

Color is dependent on the light source, and the angle
• Sun, Blue sky, Cloudy
• Fluorescent, Incandescent lighting
• Shadows
• Glancing angle of light or Perpendicular angle of light.

Tags: lighting