A Study In Clears

**benven** · **10-06-07, 10:48 AM**

So, I had a bunch of clear mediums and polyurethanes on hand. Found some red, green, blue and white paper in my kids craft section. Decided to see if different clear mediums show any major differences. I dabbed small amounts, with my finger, on each piece of paper. I wrote what the was medium under each spot. I even tried a few mixes. All pictures are under flash. Was really interested in looking at gloss and colour. And yes, I washed my finger between each change in medium

.

A couple of observations:

1. Notice how bad the Behr Faux Glaze really made red look.
2. Notice how orange the polys look on the red paper
3. Behr Flat Deep Base and Faux Glaze are the flattest of all of the mediums

Let's discuss! Anymore testing I should be doing?

**mechman** · **10-06-07, 10:57 AM**

Ben,

Well initially looking at this, the satins really add a lot of sheen. Which one pushed red the least towards orange? It seems like the first 1:1:1 mix - Deep base, satin poly and matte poly. Which satin and matte's did you use for those?

mech

**benven** · **10-06-07, 12:23 PM**

You are correct mech. The 1:1:1 Deep Base, satin poly, matte poly shifted red the least towards orange. And it is nice and flat.

All of the products are listed in the pictures. The deep base and matte poly are Behr products and the satin poly is by Varathane. i find the Varathane to be less stinky than Polycrylic by Minwax.

**wbassett** · **10-06-07, 04:21 PM**

Ben this is the sort of thing I really wanted to see and test too. We know that not all 'clear' coatings are really clear.

Empirical testing is the fastest way to quickly evaluate things that is for certain. I think it would be interesting and fun to test some of these and determine if there is any color shift and if so if it is consistent no matter what the color base it is applied to. Then we'll know exactly what it's doing to the screen and in which direction.

I was also pointed in the direction of some hardwood floor clear coatings.

Again, I want to say from my perspective yes we know certain things do work, but I also think we can do better, and benven this is a step in that direction!

**benven** · **10-06-07, 05:06 PM**

I would think hardwood floor coatings would not come in matte/flat? At least the ones I have used have always had a nice sheen to them. I guess that's what they are made for!

Hey, if anyone can spectro these, I can mail the sheets away. If a larger area is required I can certainly paint up some pieces of paper with the various products. Just let me know.

**mechman** · **10-06-07, 05:13 PM**

Quote:

benven wrote:

Hey, if anyone can spectro these, I can mail the sheets away. If a larger area is required I can certainly paint up some pieces of paper with the various products. Just let me know.

Ben,

I was planning on pm'ing you when I get mine back from X-Rite!

Should be next week some time I'd guess. I'm heading out to a hockey game tonight so I'll pm you my address tomorrow. Sound good?

mech

**benven** · **10-06-07, 05:19 PM**

Sounds good mech. Do you need a larger area of coated paper? Or are my 1" circles large enough?

**wbassett** · **10-06-07, 07:08 PM**

Quote:

benven wrote:

I would think hardwood floor coatings would not come in matte/flat? At least the ones I have used have always had a nice sheen to them. I guess that's what they are made for!

Hey, if anyone can spectro these, I can mail the sheets away. If a larger area is required I can certainly paint up some pieces of paper with the various products. Just let me know.

You're right, most don't but there are a few that do.

**wbassett** · **10-07-07, 03:44 AM**

Has anyone else noticed this?

My screen is a bit higher than most peoples because I have to shoot over a 55" Sony SXRD HDTV. I built a custom stand to lower the set some so the bottom edge of my screen is right around 48" off the floor. I have a few test panels up right now, one with poly, and I noticed from a seated position the poly coated panel is lighter, but when I stand up it looks darker. It's definitely happening and I will try to capture it on camera tomorrow. I was doing screenies tonight and it would have been too much work tonight to keep adjusting the tripod. As is I started around 10:30 and just finished a few minutes ago. (Screen shots take longer than people think)

Anyway, I was wondering if anyone else saw this. For most who's screen is lower than mine it probably won't matter, but it is definitely happening.

**mechman** · **10-07-07, 08:13 AM**

Quote:

benven wrote:

Sounds good mech. Do you need a larger area of coated paper? Or are my 1" circles large enough?

1" circles will be just fine! I'm gonna pm you my address now.

Thanks!

mech

**mechman** · **10-07-07, 08:20 AM**

Quote:

wbassett wrote:

Has anyone else noticed this?

My screen is a bit higher than most peoples because I have to shoot over a 55" Sony SXRD HDTV. I built a custom stand to lower the set some so the bottom edge of my screen is right around 48" off the floor. I have a few test panels up right now, one with poly, and I noticed from a seated position the poly coated panel is lighter, but when I stand up it looks darker. It's definitely happening and I will try to capture it on camera tomorrow. I was doing screenies tonight and it would have been too much work tonight to keep adjusting the tripod. As is I started around 10:30 and just finished a few minutes ago. (Screen shots take longer than people think)

Anyway, I was wondering if anyone else saw this. For most who's screen is lower than mine it probably won't matter, but it is definitely happening.

My ceilings aren't tall enough for me to try this. But as things are, I've never noticed anything like it.

mech

**cynical2** · **10-07-07, 08:35 AM**

Ben, this is great stuff! Such a simple idea, in hindsight (wish I'd thought of it).

A simple test like this (reinforced by mech's measurements) can go a long way with recommendations for the best topcoat to use without introducing a color shift.

So, thanks for doing this guys! I'll be watching for the outcome.

**wbassett** · **10-07-07, 04:53 PM**

Quote:

mechman wrote:

My ceilings aren't tall enough for me to try this. But as things are, I've never noticed anything like it.

mech

Yeah my screen is up higher than most people would have their screen. I'm sure it's not a problem under normal setups, but it is definitely there. Interesting though.

**GbrNole** · **10-07-07, 09:42 PM**

bottom of my screen is at 45" so i'm another one with an elevated panel.

**mechman** · **10-25-07, 03:01 PM**

Took a while but I've got the readings for all of the clears. I've attached the excel spread sheet file. I've also forwarded them on to Bill and Jim so that they can plot them on a CIE chart. I'm also going to work on putting them into a post for those that are excel deficient.

mech

**mechman** · **10-25-07, 03:18 PM**

Before I start I think it should be mentioned that these readings were done using colored construction paper. It would probably be interesting to see these readings taken again using something less permeable, such as a laminate I guess.

There are 11 readings per sheet and three measurements per reading. The 11th reading is of the paper itself. Here's where they were basically taken on each sheet:

The first numbers are for the whitish sheet, the second is for the red sheet, third is for the green sheet and the last is for the blue sheet.

1. Behr Clear Matte Poly

219 206 184
82.6 0.65 12.7
0.339 0.355 62.7

215 95 115
56.0 49.0 12.7
0.452 0.306 23.9

87 160 106
60.0 -34.9 20.9
0.292 0.430 28.1

100 121 175
51.2 7.04 -31.4
0.240 0.235 19.4

2. Varathane Satin

214 201 179
81.5 1.10 12.6
0.340 0.355 59.4

204 71 95
49.8 54.3 15.4
0.486 0.302 18.3

61 145 94
54.0 -37.3 19.3
0.280 0.438 22.0

84 107 165
45.7 8.30 -34.3
0.229 0.219 15.0

3. Behr Faux Glaze

219 209 186
84.0 -0.06 12.6
0.337 0.355 64.1

198 84 112
51.8 48.0 7.07
0.442 0.294 19.5

81 158 107
59.3 -35.7 19.5
0.287 0.428 27.4

103 126 176
52.9 4.91 -29.0
0.244 0.244 21.0

4. Liquitex Matte Varnish

217 204 183
82.6 0.81 12.3
0.338 0.354 61.4

208 82 103
52.3 51.8 14.0
0.470 0.304 20.4

60 145 98
54.1 -36.9 17.5
0.277 0.430 22.1

86 110 165
46.7 7.19 -32.7
0.232 0.226 15.8

5. Liquitex Matte Medium

214 202 174
81.6 -0.16 15.6
0.334 0.362 59.6

202 79 101
50.8 50.6 13.3
0.468 0.303 19.1

71 150 95
56.0 -37.0 21.6
0.287 0.442 23.9

89 113 162
47.8 4.65 -29.1
0.238 0.238 16.6

6. Tri-Art Matte Polymer Medium

218 206 178
83.1 -0.68 15.7
0.343 0.362 62.4

210 86 105
53.4 50.6 14.4
0.466 0.307 21.4

78 156 104
58.5 -36.2 20.2
0.287 0.432 26.5

92 119 168
49.8 3.69 -29.1
0.238 0.241 18.3

7. Deep Base

217 207 186
83.4 0.05 11.5
0.335 0.353 62.9

202 84 111
51.9 49.5 8.90
0.450 0.296 20.1

90 163 110
61.1 -34.6 20.3
0.291 0.426 29.4

101 126 176
52.9 4.14 -29.1
0.242 0.244 21.0

8. 1:1:1 DB/Satin/Matte

218 206 184
83.2 0.54 12.3
0.338 0.354 62.5

204 80 105
51.4 51.2 11.4
0.462 0.299 19.6

79 157 104
58.6 -36.2 20.5
0.287 0.433 26.6

96 119 172
50.2 6.16 -31.0
0.238 0.235 18.6

9. 1:1:1 Deep/Satin/Matte

218 206 182
83.2 -0.05 13.4
0.339 0.357 62.5

203 80 105
51.1 51.0 11.5
0.463 0.299 19.4

70 154 101
57.4 -37.7 20.1
0.283 0.435 25.3

92 118 170
49.6 4.77 -30.6
0.236 0.236 18.1

10. 1:1:1 Satin/Matte/Polymer

217 205 181
82.8 0.16 13.4
0.339 0.357 61.8

210 84 106
53.0 51.5 13.3
0.465 0.303 21.0

96 161 119
60.9 -30.3 15.3
0.289 0.405 29.1

93 116 169
49.2 5.84 -30.9
0.237 0.234 17.8

11. Paper only

219 208 189
83.9 0.68 10.7
0.335 0.350 63.9

207 93 119
54.5 47.6 7.75
0.437 0.297 22.4

87 161 110
60.5 -34.7 19.6
0.289 0.425 28.6

105 130 179
54.3 3.87 -28.7
0.244 0.247 22.2

I'll have more as the day wears on as well as the CIE charts if either Jim or Bill get to them. I'll re-verify these numbers when I actually get my spectrophotometer back. I don't anticipate any changes though.

mech

**mechman** · **10-25-07, 03:22 PM**

Here are shots of the sheets themselves. You've seen the whitish one above.

I'll be adding stuff as the day wears on...

mech

**GbrNole** · **10-25-07, 03:31 PM**

almost seems like a 50/50 mix of behr matte poly and behr faux glaze might be the best compromise of that bunch?

edit: check that, 50/50 of deep base and faux glaze is what i meant to say.

**benven** · **10-25-07, 04:43 PM**

You the man, mech! Need to digest the data.

I didn't do a 50:50 Deep Base to Faux Glaze, but the Faux Glaze kills red on it's own.

**cynical2** · **10-25-07, 10:48 PM**

I've done a bit of data reduction. I'm a believer that the deviation of x and y in the CIE space is probably the simplest set of numbers to look at if we want to get an idea of the effect of the clearcoats on color.

That being said, plotting the deviation (as a scalar) doesn't tell us which direction the color is moved from it's original. But, it's enough to get a quick look at how much the clearcoats effect the color. So, here we go:

Thanks to benven for starting this effort and mech for the measurement data.

**mechman** · **10-25-07, 10:55 PM**

I'd like to redo it with something other than construction paper sometime too. And I mean no offense to Ben but some of this may be from the coatings soaking in. I may have to start looking for some of these and do them on a laminate sample sometime in the future.

mech

**mechman** · **10-25-07, 11:05 PM**

I've also changed the title as I think we've moved beyond 'empirical'. It does appear that the glaze and the base have the least effect upon the color so far.

mech

**benven** · **10-26-07, 07:21 AM**

Good one GbrNole. I didn't look at the data, but rather what my eye saw. And it looked, by eye, that the Faux Glaze did horrible things to red. Boy, just goes to show you how deceiving these things can be. And that without measurements, you are simply guessing, like I was.

Nice graph Jim. That tells us the story. Fauz Glaze and Deep Base, like GbrNole and mech stated, have the least effect on the base colour.

mech, no offense taken. I just had some paper around and wanted to see the effect. Just having some fun with this. I believe the art store where I purchased the white foam board has red, blue and green foamboard. If I have some time this weekend, I'll go see what they have and repeat. And yes, we have now moved away from empirical.

It's ironic, my very first screen, which is still on the basement wall but now full of dings from hockey sticks and balls and pucks, had a topcoating of 1:1 Fauz Glaze and Deep Base. That was not easy to roll!

**wbassett** · **10-26-07, 09:39 AM**

Quote:

mechman wrote:

I'd like to redo it with something other than construction paper sometime too. And I mean no offense to Ben but some of this may be from the coatings soaking in. I may have to start looking for some of these and do them on a laminate sample sometime in the future.

mech

I agree the construction paper was a great start but it also drinks in a lot of the material being tested. Now we should move on to a couple of things like testing against something close to what a DIY screen would be comprised of, or for a second round something less porous. Also, I may have missed this, but did you take readings of just the paper with no clears applied so we can get a baseline. From there we can start to identify and color shifting and in which direction.

I don't have all the clears that are being tested here, and am trying some tests of my own that are also looking interesting. When I get everything sorted I'll post those results. What I am doing is applying the Behr poly to a piece of glass in different amounts of thickness. You really can see if it's clear or not that way. As we would conclude, thin coats are the best, thicker coats or poor application techniques can go cloudy quick. Ideally I'd like to see a clear coating that remains clear but still adds that diffusive layer to the screen. These are the types of tests that will shake out something. Great job so far guys!

**cynical2** · **10-26-07, 09:46 AM**

Quote:

wbassett wrote:

I agree the construction paper was a great start but it also drinks in a lot of the material being tested. Now we should move on to a couple of things like testing against something close to what a DIY screen would be comprised of, or for a second round something less porous. Also, I may have missed this, but did you take readings of just the paper with no clears applied so we can get a baseline. From there we can start to identify and color shifting and in which direction.

I don't have all the clears that are being tested here, and am trying some tests of my own that are also looking interesting. When I get everything sorted I'll post those results. What I am doing is applying the Behr poly to a piece of glass in different amounts of thickness. You really can see if it's clear or not that way. As we would conclude, thin coats are the best, thicker coats or poor application techniques can go cloudy quick. Ideally I'd like to see a clear coating that remains clear but still adds that diffusive layer to the screen. These are the types of tests that will shake out something. Great job so far guys!

Bill, yes baseline readings on just the paper were taken. The plot above is how much the x- and y-values changed vs just the paper for each of the clears, on each of the four colors. I just plotted the magnitude of the change (square root of the sum of the squares of the difference between the paper baseline values and the "with clearcoat" values). As I said, I didn't get into which direction the color was pushed, as that's a much more extensive exercise. But, I could relatively quickly luck at the magnitude of the push in CIE space.

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