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Gloss Meters 101

While typically associated with high end detailers who are trying to extract the highest level of clarity and gloss from automotive paint, the gloss meter is used to measure shine or luster on a smooth surface. The person(s) using these meters are typically looking for a certain range or standard that indicates a high level, or “good” reading, or they are looking for comparative readings to indicate percentages of increase in gloss ranges.

Gloss meters are good for providing at least some level of qualitative results, as opposed to the all-too-common method of standing back and saying: “yeah…it looks good!”. The detailing industry is overly subjective when determining how good a car looks, or how much improvement has taken place. What looks “great” to one person may only look “good” to another…and without having the ability to actually measure this, then our statements or reviews simply lack validity.

So at this point in the article, you’re probably drawing the conclusion that I am recommending that everybody goes out and buys an expensive gloss meter, right? After all…we need some kind of device to post results in a qualitative manner.

Actually, I’m here to break the bad news that gloss meters fall short in determining just how good a surface looks, and the readings can be deceptive because it doesn’t measure how our eyes see and perceive a finish. Sure, it’s better than nothing, but you simply cannot evaluate paint, polishing methods, polishing tools, coatings, etc. with just a gloss meter as it doesn’t provide enough information.

Below is a perfect example as to why a gloss meter can provide us with a false sense of security, and fall short of giving us a true indication on how good a painted surface really looks. Both of these pieces started out with almost identical gloss readings! But having said that, I don’t know anybody (who has good vision) that would say that they look equally as good. The piece on the left has so much texture and orange peel (waviness) in the finish that the reflections are distorted and hazy. The finish on the right has been leveled and polished to remove both texture and orange peel, providing a very clear reflection. If you were to rely on a simple gloss meter, it would seriously fall short of telling you the whole story.



Here’s another example of two surfaces with very similar gloss readings, but one clearly has a better finish that everybody would prefer. In this one, we used a process that allows us to remove the fine texture in the clear coat, but we don’t get so invasive as to remove orange peel. What we are doing here is creating a higher level of clarity, or image quality in the reflections. This is what we perceive as gloss. The meter shows the same gloss, but our eyes and brain processes them as completely different from one another…with the texture-free surface appearing as a “glossier finish”.



At ESOTERIC, we do consulting work, training, and supply products to OEM automotive manufacturers, which gives us a decided advantage over others within the detailing business. We get to see technologies that nobody else does…technologies that are funded by extremely large budgets! One might assume that an OEM manufacturer uses gloss meters to determine whether or not their painting processes are achieving set goals or standards. In actuality, they use technologies that far surpass anything that a simple gloss meter can provide. When OEM’s are grading paint finishes, they are using Wave Scan DOI (Distinctness Of Image) meters that look at LW (long wave) and SW (short wave) readings among other things. Once they have set their standards amongst all of the measurements, they can quickly scan a surface to make sure that it meets their requirements. While these meters do not detect gloss directly, they can quickly infer that gloss is where it needs to be based on all of the other, more critical and precise measurements.

OK, so it must be time to go out and buy a Wave Scan DOI meter to get the most definitive results, right? Well, unless you’ve got a spare $38K or so sitting around, that’s not an option. This technology is very advanced, and very expensive.

I think I can safely speak for the entire detailing industry by saying that we’re not going to invest that kind of money on a tool that will give us definitive results.

The next step is to look for an alternative…one that will bridge the gap between a standard gloss meter, and the $38K wave scan DOI meter. Do we have technologies that will measure gloss, plus provide us with readings similar to what the OEM manufacturers are going for?

Enter the Rhopoint IQ

Fortunately for us budget-limited businesses in the detailing industry, we do have a tool and technology that will provide us with measurements that directly relate to what we are trying to achieve, plus a few more that aren’t available in the ultra-expensive tools used at the OEM level.

As we previously discussed, the gloss reading is nice to have, but it fails at giving us the true image quality (IQ).

The Rhopoint IQ measures not only gloss but also other image quality parameters such as: DOI, RIQ, Haze and RSPEC , it is the only hand held instrument that profiles how light is reflected from a surface.

From the manufacturer:

The Rhopoint IQ Measures

  • 20° Gloss
  • Haze
  • Distinctness of Image – DOI
  • RIQ (Reflective Image Quality)
  • RSPEC (Specular Reflection)

What is DOI ?

DOI, Distinctness of Image, is a measurement indicating the QUALITY OF THE GLOSS. How clearly can a reflected image appear.

Symptoms of poor DOI: Orange peel, brush marks, waviness or other structures visible on the surface. Poor finishing. Reflected images are distorted.

What is RSPEC ?

RSPEC is the peak gloss value over a very narrow angle.
RSPEC is very sensitive to small changes in texture and is used to identify subtle differences in surface smoothness.

What is RIQ ?

RIQ is a superior measurement to DOI with expanded capabilities.RIQ quantifies ORANGE PEEL qualitatively as well as measuring surface waviness. RIQ is a HIGH RESOLUTION DOI measurement and correlates better with human vision and perception.

Orange Peel, brush marks, waviness, cause reflected images to be distorted.

Reflectance Haze with the Rhopoint IQ

Reflectance Haze is an optical effect caused by microscopic texture or residue on a surface. A milky finish is apparent on the surface causing a loss of reflected contrast, halos and patterns can be seen around reflections of high intensity light sources..

Causes: Poor dispersion, raw material incompatibility, additive migration, vehicle quality, stoving/drying/curing conditions, polishing marks, fine scratches, ageing, oxidisation, poor cleanliness/surface residue.


A measurement proportional to the amount of light reflected from a surface.

Geometry: For best results the correct measurement geometry should be chosen based on the reflectance of the material. 20° is the ideal angle to measure high gloss surfaces such as automotive finishes.

Now that we have identified the Rhopoint IQ as the perfect solution to the needs of the detailing industry, let’s take a close look at  what it can tell us in real world detailing and testing.

Let’s go back to the first before and after photos we looked at earlier in the article. We talked about how the gloss readings were almost identical, and agreed that the two finishes couldn’t look any more dissimilar unless they were different colors!

Here are the readings before and after photos (the new “50/50” standard!) showing the meter readings. You will see that the difference in gloss is only one tenth of one percent, but the big changes are with the other readings. The RIQ (Reflective Image Quality) went from 77.1 to 95.7…a 24.1% improvement. RSPEC went from a very low 56.6 to 83.5…a 47.5% improvement. Those are very significant increases in image quality and clarity.



Now for another example, let’s look at the paint on this Z06 Corvette. All you need to do is look at the different measurements to see that the paint has gone through a major transformation. When we stepped back and looked at it, we knew that it looked like a completely different car. But now that we are using the Rhopoint IQ, we know exactly how much improvement. Gloss went from just 56.0 up to 93.4…a massive 66.8% improvement. RIQ went from 88.4 to 95.8…an 8.4% improvement. RSPEC went from a very low 46.9 to 93.5…a 99.4% improvement!



What does the Rhopoint IQ mean to the detailing industry?

Change. BIG change!

Not only will tools like this enable the industry to quantify results, but it will also push it into modern times where subjective claims are no longer acceptable. The measurements that the IQ provides do not lie, and no amount of creative copywriting can overcome shortcomings discovered in the numbers. So by adopting this new technology, product and tool manufacturers will now have the ability to improve product development and manufacturing since subjectivity will be taken out of the equation.

And for detailers, the IQ will provide the opportunity to:

  • Evaluate finishes, and provide real data to customers. Think about how nice it would be to assign definitive improvement figures relative to levels of service!
  • Test / evaluate polishes to determine which ones actually provide a better finish.
  • Test polishing techniques.
  • Test / evaluate tools and pads.


The detailers who embrace this technology, and use it to better develop their systems, will be at a distinct advantage over those who do not. Not only will it show your commitment to the trade, but it will also provide you with hard data that you can share with your customers. Imagine for just a minute that you are the customer who is shopping for a high level detailer. One detailer you speak with tells you that it will look “a lot” better, and the other tells you that you can expect a 20-25% increase (for instance) in image quality…verifiable. I’m going out on a limb here to say you’re probably going to choose the one who can qualify his / her statements.

Another test we have performed is with paint protection film to determine which manufacturer provides the best clarity. We will be sharing those results soon!

As always, we certainly appreciate you taking the time to read our articles here on the Esoteric Car Care Learning Center. Please feel free to share our work and research on your favorite automotive forums and social media.

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New Albany, Ohio