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Robin E. Snyder Senior Member Username: robin
Post Number: 356 Registered: 08-2004
| Posted on Thursday, April 07, 2011 - 04:38 pm: | |
I have a coping and an adjacent metal panel that appear to be different in color, although they are supposed to match. The color is a silver Mica/Metallic color. Manufacturer is referring to AAMA 2605 which allows 2 Delta Es from the approved standard. I have a few questions: 1. Can anyone explain what this means? 2. What language do you include to help address this type of situation in the specs? |
(Unregistered Guest) Unregistered guest
| Posted on Thursday, April 07, 2011 - 04:56 pm: | |
Could be a difference in coating methods. Coil based, or baked on? If you notice, Durnar and Valspar and similar coatings have two primary application methods, and they result in similar, but not the same, sheen/color/appearance. |
David Axt, AIA, CCS, CSI Senior Member Username: david_axt
Post Number: 1174 Registered: 03-2002
| Posted on Thursday, April 07, 2011 - 05:24 pm: | |
Mica and metallic paints are directional. That is to say that when the paint is sprayed the flakes lay down in a directional pattern. Therefore depending on the direction of the panel, you could get a different look. |
Steven Bruneel, AIA, CSI-CDT, LEED-AP Senior Member Username: redseca2
Post Number: 268 Registered: 12-2006
| Posted on Thursday, April 07, 2011 - 05:42 pm: | |
From AAMA 2605 - 7.1.2: "Pearlescent mica and metallic flakes reflect and scatter light in random patterns; therefore, exact color uniformity should not be expected. Slight color shifting should also be expected when viewing from varying angles and distances." When reviewing "metallic" like finishes we always look at them in natural sunlight, both direct sunlight and in the shade on an otherwise sunny day. Try putting a metallic finish sample on a turntable (or simply turn it around) and many will change dramatically, very similar to turning a polarizing filter on a single lens reflex camera. Your two samples might be identical in color chemistry but with different orientations of the mica chips when the two components are placed in their as-built relationships. In a personmal note - Years ago I had a Peugeot car from France. Nice car, but the metallic paint finish was applied in the factory with an electric charge applied to the body to control the metallic chip orientation. This could never be reproduced in you local body shop and a fender bender might result in a complete repainting of the car to assure a uniform appearance. |
John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick
Post Number: 1312 Registered: 03-2002
| Posted on Friday, April 08, 2011 - 12:52 pm: | |
I believe that true metallics are more subject to the orientation issue than micas are, so you may want to ask the product manufacturer about this. The "delta E" reference is for color change in South Florida sun - also called the "Hunter" test. It is not related directly to the presence of metallics. The AAMA finish standards include a requirement for color fading. As to control, I think you will be hard-pressed to truly match an existing metallic. Requiring custom-colors, with samples submitted, is the surest way, but more expensive (depending on the quantity of finished product) and much slower for delivery time due to the approval process. Alternatively, get lots of samples now, find an acceptable match, and make a proprietary specification. |
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