Thermal Light 4+

Crystal Clear Solutions

Designed for iPhone

    • 2.6 • 5 Ratings
    • $1.99

iPhone Screenshots


Thermal Light is the first of its kind app that uses black body radiation of an object (iron/steel, copper, ceramics) to determine temperatures between 1000F and 2700F. Very hot objects irradiate light; the app uses this light to determine the temperature between 1000 and 2700F. The app has been calibrated against a certified IR thermometer. Why spend $900 for an IR or optical thermometer when you can convert your iPhone to do the same thing? This is great for knowing the temperature of your steel for working. Temperature increments are 50F.

Please go to support website for more details at

What’s New

Version 1.211

Low temperature setting algorithm adjusted.

Ratings and Reviews

2.6 out of 5
5 Ratings

5 Ratings

Ruger. Colt. Winchester. ,

No luck.

I thought this would be handy for HTing knives, but I haven't had any luck with it. I tried calibrating then using it to read a steel that I knew the austentitic temp for, in light and dark, but could not get an accurate read.

TomKinForge ,

Dead app please update

I love this app and have used it for years to double check my heat treat oven calibration

It is no longer compatible with iPhone OS and does not work at all now

If they ever update I’ll change my review to 4 stars

Bill T2 ,

Metal casting furnace

Of all the apps I have bought this one is almost totally useless. To calibrate you are supposed to point it at a light and keep trying until you get the x in the magic spot. So I do this for the low temp then the high. But find out that whatever one you have it calibrated it losses the previous calibration. Oh well I think I can work around that so I calibrate it again for the low temperature. Note: I did this in my garage at night. Then stepping outside to where my metal melting furnace is running. Now the thing says it needs calibrated again. So one more time trying to calibrate this at the operating furnace. I can not get it to calibrate looking down in the glory hole where my crucible is. This even though the crucible is red hot . At this time on a scale of one to ten = 0

App Privacy

The developer, Crystal Clear Solutions, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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