The human eye can identify 4 shades of Grayscale imagery under stress, but many manufacturers use between 30-246 shades of grayscale. In teaching this curriculum internationally, we have discovered that firefighters don’t respond to gray scale (much to the displeasure of many thermographers and TIC manufacturers). When these color palettes are used in high temperature environments they can confuse firefighters and produce a very obscure image. These color palettes were designed for specific industrial applications in lower contrast and lower temperature environments NOT for the Fire environment.
Therefore, it is imperative that the firefighter know and understand their specific brand/model of TIC and it’s benefits and limitations.Īnd in many cases, thermal imaging manufacturers offer various other color palettes that are NOT intended for the fire environment such as: rainbow (high color), iron bow, all grayscale, reverse polarity (sometimes known as Inverse or Black Hot), Green Hot, and more. In many cases, fire service thermal imaging camera manufacturers pick and choose which temperature they want colorization to appear and it can be detrimental to a firefighter to rely on seeing color as an indicator of severe heat if the manufacturer chooses to follow the color/temperature progression as shown below in the MSA color palette. Why is this? Doesn’t this confuse firefighters when they pick up one TIC that fails to show color until 1000 degrees Fahrenheit when another brand shows colorization at 500 degrees? What happens when we associate colors with specific dangers and fail to recognize the severity of the thermal threat in gray scale? Notice that there is no uniform standard “corresponding, temperature-dependent” for each color. “The colors yellow, orange, and red shall have a corresponding, temperature-dependent change in hue as temperatures increase” Details within the thermal image and within the colorized area shall remain resolvable by the user other than at saturation.” “Colorization shall overlay the grayscale thermal images produced by the thermal imager. According to NFPA 1801 (Standard for Thermal Imagers for the Fire Service section 6.6.4.2.2 & 6.6.4.2.3) colors should meet the following criteria:
This is the NFPA 1801 approved color/temperature progression for thermal imaging cameras under the TI Basic Color Palette (black, grey, white, yellow, orange & red). Why is this so? Doesn’t NFPA 1801 standardize this issue and prevent confusing color temperature associations? Sadly, this isn’t the case. Have you noticed that there are numerous color palettes and color temperature associations with fire service thermal imaging cameras?
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