Fun with a Gloss Meter ;)

WRAPT C5Z06 said:

According to Todd Cooperider, meters are nowhere near as DOI meters.

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What is a DOI?

Oz_TCH said:

Dumb question. Do these meters measure surface gloss reflection only ? but not the deepness and dimension ?

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There's no "dimension" and "depth" to gloss. Gloss is by definition the specular reflectivity of a surface, and only that. That said, the human perception of reflection and "gloss" as in layman's terms, and overall appearance of a surface is incredibly complex, and a gloss meter doesn't even make an attempt to replicate that by any means. That's the exact reason why a gloss meter is not really useful for judging the overall appearance of the paint, and why it shouldn't be trusted over human eyes when it comes to judging how a polish, a coating, etc. might affect that.

Human judgement of gloss might be subjective, but because anybody looking at the car will also use his "subjective" eyes and not an objective gloss meter to assess the perfection of the paint and reflection, we should generally work towards catering for the latter (ie. human eye), not for the gloss meter's readings, especially if the two deliver conflicting results.

rlmccarty2000 said:

What is a DOI?

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Distinctiveness Of Image. It is used to measure the "hazing" of the surface and the "blurring" of the reflected image. Subtle hazing won't necessarily effect the overall amount of gloss (as measured by a regular gloss meter), but will definitely appear less "glossy" (as in layman's terms) to the human eye.

I'm going to confirm that 60 degrees is the best angle to measure paint. 20 degrees has the best resolution for high gloss surfaces, in a perfect world where everything we're measuring is 100% flat this would be the angle to go with. On car paint, there's too much room for error, so if I measure a spot on the test hood at 20 degrees I'll get a number, say 89GU. Very slightly tilt left or right and it can bump up say +6GU. So on a slight curve this can significantly impact measurement accuracy. At 60 degrees, the measurement you get without putting any left or right pressure bias on the meter generally reads the highest GU, tilting very slightly left or right will reduce the gloss measurement.

Tomorrow I'm planning on putting the jeweling theory to the gloss test.

WRAPT C5Z06 said:

According to Todd Cooperider, meters are nowhere near as DOI meters.

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I forgot a few words..lol. I meant to say, gloss meters are nowhere near as effective as DOI meters.

WRAPT C5Z06 said:

DOI meters.

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Could you recommend one ?

Ronin47 said:

I think you missing the point. My meter is on the way, will post what I use it for and my findings, I know this will be used as much if not more than my PTG.

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did you get it and tested ? Which model you got ?

I've waffled on fun-money spends for such a tool but after looking back at all my jobs from last year and even the customer who dropped a car off last night, I'm leaving the very best gloss meter around as my eyes and theirs. When he saw my car next to his - mine is black metallic and his a dark gray metallic, his first question was like "HOLY BEEP....is my car going to shine like yours?" and I had to LOL as he noticed the gloss level even through the rain and dust it's seen for the past week. I then wiped down the hood and fender showing him some good day-forward rinseless technique and he was floored.

THAT'S! a true and valuable gloss meter to me. 90-100, etc. whatever number it has he's going to see his car completely differently once I'm done with it and he won't be disappointed for sure. He won't need a number to quantify it.

All that said, I think what he and many if not all of my customer notice isn't just the "gloss" or reflectivity. That's cool and all but we don't see static objects from just one angle or viewpoint. IMO what customers jump up and down at is as they walk/move around their car, the lighting causes the appearance of a dance or movement of the light as the design of the car jumps out at them when the light bends around the curves and edges. It's almost magical and anyone here who has stepped back and admired their own work knows what I mean.

I also think beyond gloss, it's the Clarity they notice. When a vehicle is clean and has a perfect finish the gloss or Depth of that clear coat jumps out. Especially on metallic finishes. The Clarity is what they then move closer to and notice. I watch customers all the time step back, soak up the movement of the light then watch as they move closer to actually look through the surface clear into the actual paint. Again, special colors and metallic paints show off well.

I had a guy with a Red Audi for the very first time notice the slight metal flake in his paint. He had the car for over 1 year and never noticed that the color wasn't actually a Pure red but it also had a slight flake to it. I had to explain to him that Misano Red is special for exactly that reason but prior to being fully corrected and offering the clarity I presented it wasn't as easily seen.

On solid colors...and I'll reference my S4 here as it was a Pure Black, the clarity enhances the appearance of the depth of the clear coat. I've had people look at my S4 and say it looked like a shiny black hole that goes on forever. They would actually look for a reference point that showed them the thickness of the clear coat but had to work to find something. Looking back I miss it because that true depth of a pure solid color is what I personally miss most. I think it also (pun intended) reflects on the quality of my work too because of the challenge they present to get that depth. Ironically, at the same time, those same colors can often present the greatest visual "gloss" or dance as I've noted when in the right light. I think the images of my car below exemplifies everything I've mentioned....but then I'm not biased am I?

Just my two cents and opinion.

Here's the "dancing light" I spoke of that people would notice. Here IMO the coating really helps show it off. McKee's 37 v1 too.




The reflectivity and mirror finish aka the "gloss"






The Depth of the finish or pureness of color

Hi Guys.
I had a short discussion with IDA master member in Poland.
He said that gloss meters for detailing are supposed to be accurate in 20 degrees.
I have just bought cheapest China with 60 degrees which is supposed to measure furniture gloss etc.

What is the difference between 20 and 60 degree in a measurement ? How bad measure can give me the gloss meter 60 degrees to 20 degree ?

Thx for advise.

I copied and paste this information from a gloss meter manufacture. And maybe you get a little more understanding about it.


How do I choose a Gloss Meter?

You first require a flat surface of approximately 2" by 0.5" (50 x 10mm) to position a glossmeter properly on a surface. If the surface area you have is smaller, then please call us to discuss the Novo Curve table top gloss meter for 2 x 2mm areas.

One must now judge your product by how glossy it is. Most products fall into a semi gloss range. Some are matte and designed to have very low gloss and others such as metals or car finishes are very high. There are three types that cover the complete range of gloss, namely the 20 degree, the 60 degree and the 85 degree glossmeters. Certain industries however suggest a different angle. These industries are; paper, ceramic, film, and vinyl). If you fall into one of these industries, please read Gloss Meter Selection by Industry. Some customers produce a range of products from very glossy to matte, then you would require a Universal gloss meter that measures all three angles or maybe you only make products from semi gloss to very high gloss, than you need the DUAL 20-60 degree gloss meter.


Low Gloss - 85°

For improved resolution of low gloss, a grazing angle of 85° is used to measure the surface. This angle is recommended for surfaces which measure less than 10 GU when measured at 60°.This angle also has a larger measurement spot which will average out differences in the gloss of textured or slightly uneven surfaces.


Medium or Semi Gloss - 60° - The Universal Measurement Angle

One must remember that all gloss levels can be measured using the standard measurement angle of 60°. This 60 degree angle is used as the reference angle for all products. So why choose some other another angle? Because for extreme gloss, one obtains better measurements with the complimentary angles of 85° or 20° often used for low and high gloss levels respectively.


High Gloss - 20°

The acute measurement angle of 20° gives improved resolution for high gloss surfaces. Surfaces that measure 70 GU and above at the standard angle of 60° are often measured with this geometry. The 20° angle is more sensitive to haze effects that affect the appearance of a surface. The different gloss of these two samples is more clearly shown in the 20° readings.

TTQ B4U said:

I've waffled on fun-money spends for such a tool but after looking back at all my jobs from last year and even the customer who dropped a car off last night, I'm leaving the very best gloss meter around as my eyes and theirs. When he saw my car next to his - mine is black metallic and his a dark gray metallic, his first question was like "HOLY BEEP....is my car going to shine like yours?" and I had to LOL as he noticed the gloss level even through the rain and dust it's seen for the past week. I then wiped down the hood and fender showing him some good day-forward rinseless technique and he was floored.

THAT'S! a true and valuable gloss meter to me. 90-100, etc. whatever number it has he's going to see his car completely differently once I'm done with it and he won't be disappointed for sure. He won't need a number to quantify it.

All that said, I think what he and many if not all of my customer notice isn't just the "gloss" or reflectivity. That's cool and all but we don't see static objects from just one angle or viewpoint. IMO what customers jump up and down at is as they walk/move around their car, the lighting causes the appearance of a dance or movement of the light as the design of the car jumps out at them when the light bends around the curves and edges. It's almost magical and anyone here who has stepped back and admired their own work knows what I mean.

I also think beyond gloss, it's the Clarity they notice. When a vehicle is clean and has a perfect finish the gloss or Depth of that clear coat jumps out. Especially on metallic finishes. The Clarity is what they then move closer to and notice. I watch customers all the time step back, soak up the movement of the light then watch as they move closer to actually look through the surface clear into the actual paint. Again, special colors and metallic paints show off well.

I had a guy with a Red Audi for the very first time notice the slight metal flake in his paint. He had the car for over 1 year and never noticed that the color wasn't actually a Pure red but it also had a slight flake to it. I had to explain to him that Misano Red is special for exactly that reason but prior to being fully corrected and offering the clarity I presented it wasn't as easily seen.

On solid colors...and I'll reference my S4 here as it was a Pure Black, the clarity enhances the appearance of the depth of the clear coat. I've had people look at my S4 and say it looked like a shiny black hole that goes on forever. They would actually look for a reference point that showed them the thickness of the clear coat but had to work to find something. Looking back I miss it because that true depth of a pure solid color is what I personally miss most. I think it also (pun intended) reflects on the quality of my work too because of the challenge they present to get that depth. Ironically, at the same time, those same colors can often present the greatest visual "gloss" or dance as I've noted when in the right light. I think the images of my car below exemplifies everything I've mentioned....but then I'm not biased am I?

Just my two cents and opinion.

Here's the "dancing light" I spoke of that people would notice. Here IMO the coating really helps show it off. McKee's 37 v1 too.

The reflectivity and mirror finish aka the "gloss"

The Depth of the finish or pureness of color

Click to expand...

See. That's a shine that I would approve of lol. I'm a hard person to please!! Good Job

Sent from my SM-N960U using Autogeekonline mobile app

Domel said:

Hi Guys.
I had a short discussion with IDA master member in Poland.
He said that gloss meters for detailing are supposed to be accurate in 20 degrees.
I have just bought cheapest China with 60 degrees which is supposed to measure furniture gloss etc.

What is the difference between 20 and 60 degree in a measurement ? How bad measure can give me the gloss meter 60 degrees to 20 degree ?

Thx for advise.

Click to expand...

I make a note of this difference in my previous reply below, but here is some more information on why I like working with the 60 degree angle better. The 20 degree angle is more sensitive to surface haze and has a better resolution for anything above 70GU. However, it is less likely to measure the peak of the gloss reading on anything that isn't 100% flat. Here's a note pulled directly from Rhopoint's newer Novo-Gloss spec sheet, these newer meters compensate for the issues I'm having measuring at the 20 degree angle:

"A major advantage of the Novo-Gloss is that it automatically compensates for curved or textured sample surfaces by virtually adjusting the measurement position. Conventional gloss-hazemeters have fixed optics which can make measurement unreliable as any sample curvature will reflect light away from the centre of the measurement sensor causing errors. The Novo-Gloss automatically adjusts the sensor position by detecting the peak of the reflected light. The laws of reflection state that the incident angle is equal to the reflection angle thus the peak equates exactly to the 20° gloss angle."

So the sensor adjusts itself regardless of the surface flatness up to a certain point to have the light reflected in the exact center of the receiver. My earlier Rhopoint's don't have this feature. When I measure at the 60 degree angle, the angle is pretty much spot on to measure peak gloss and any very slight tilting to the left/right/up/down is generally going to reduce the reading. The assumption is that I'm more likely to hit the center of the receiver at this angle. Whereas on the 20 degree angle, if I adjust slightly left/right/up/down I can achieve higher readings than the reading of me putting zero pressure on the meter. I don't want to have to make any pressure adjustment for the meter to measure the peak gloss. All else equal, considering all angles are calibrated properly, GU measured at the 20 degree angle will be slightly lower than those measured at the 60 degree angle, and even lower than those measured at the 85 degree angle when working on a high gloss surface (90GU). It just means you have to list the angle you're measuring with when you release gloss measurement results.

Loach said:

I'm going to confirm that 60 degrees is the best angle to measure paint. 20 degrees has the best resolution for high gloss surfaces, in a perfect world where everything we're measuring is 100% flat this would be the angle to go with. On car paint, there's too much room for error, so if I measure a spot on the test hood at 20 degrees I'll get a number, say 89GU. Very slightly tilt left or right and it can bump up say +6GU. So on a slight curve this can significantly impact measurement accuracy. At 60 degrees, the measurement you get without putting any left or right pressure bias on the meter generally reads the highest GU, tilting very slightly left or right will reduce the gloss measurement.

Click to expand...