Presently, paint sheen (how shiny a paint is) is integrated into paint at the time of manufacture, not added in.

When one selects amongst buying a particular color of paint paint that's flat, gloss, semigloss, satin, matte, etc., one is selecting amongst different cans (each of which dries to a particular sheen), to which pigments to produce your desired color are stirred in.

Why not devise sheen additives, which could be added to the paint base, to produce the desired sheen?

Besides offering users of paint vastly more variety to choose from (based on the resolution of the sheen additive dispenser), it also would allow paint retailers to keep *much* less paint in stock.... as much as an 80% reduction in varieties of paint bases, while still being able to make every color and sheen.

With this invention, a retailer wouldn't need to keep seperate inventories of gloss white, semigloss white, satin white, eggshell white, flat white. Instead, he would just have one type of white, which he could alter to any of those sheens.
-- goldbb, Oct 05 2009

What makes paint glossy? http://blog.raiderp...s-paint-glossy.html
[phoenix, Oct 05 2009]

Martin on the left... http://www.bergprop...-martin-sheen-b.jpg
...Charlie on the right [normzone, Oct 05 2009]

yes, that would be nice. any idea how it could be done? I'm sure that <DOW> and DuPont would be very interested.
-- WcW, Oct 05 2009


Not entirely sure, since I can't seem to find on the web enough info about the chemistry of how paints develop their sheens.

However, even without knowing the chemistry, I would suspect that if appropriate storage and mixing machines can be put into the retail store, we could reduce the number of paint bases to just pre-made "gloss" and "matte" and mix the two as needed to get in-between sheens.

That would require more storage, and measuring larger amounts of fluid, than using a mere additive, though.

It would be like making grey paint by mixing black paint and white paint, instead of adding black and white pigments to uncolored paint.
-- goldbb, Oct 05 2009


From my link:

"The surface luster or shine of dried paint is created by the ratio of pigment to binder. In the painting industry, this ratio is called the pigment volume concentration (PVC)..."
"A higher PVC results in flatter finishes, while lower PVC will give a finish a glossier appearance."
-- phoenix, Oct 05 2009


can we easily modify that at the point of sale? I know that many paint color formulations include matting agents but glossing must require a lot of additional mixing.
-- WcW, Oct 05 2009


// That would require more storage, and measuring larger amounts of fluid, than using a mere additive, though.//

Actually it would be less because you would keep the gloss/matte additives in a couple oil drums while stocking less paint variations on the shelves. Right now you have 3 to 4 base colors (ready for tinting) in 4 different types of finishes.
-- Jscotty, Oct 05 2009


One would think that if it were this simple, paint manufacturers would already be doing it. So it becomes a matter of figuring out why they are not. It can't be because they simply haven't thought of it.
-- tatterdemalion, Oct 05 2009


//if it were this simple, paint manufacturers would already be doing it//
right... and *why* would they do this ?

I imagine you can do this at a real paint store where they blend their own. There's one not too far off; I'll check if I think of it.
-- FlyingToaster, Oct 05 2009


// There should be a particular grade called "Martin". // That could be the brand name for this entire process.
-- tatterdemalion, Oct 05 2009


It took me a little while, but I got it. One of our "choises" (link)
-- normzone, Oct 05 2009


Whenever I watch one of those Discovery Channel shows where they rebuild an old car, near the end of the episode they always show a clip of the guy in the paint shop with the plastic cup who is making up his own formula for the color just before he sprays it. Could he be formulating the sheen level too?
-- Jscotty, Oct 05 2009


In the olden days, you would add varnish to oil based paint to make it more glossy. This was only done to the final coat. (Source - my old copy of "The Complete Handyman".)
-- spidermother, Oct 09 2009


I work in a hardware store, and we do mix paints.

The amount of pigment we add (in the store) to the paint is the same for flat and glossy paint. The only difference is the base to which the pigment is added.

So the ratio of pigment to binder can't be the sole determiner of sheen, since the amount of pigment added is constant (an ounce to a few ounces), and the amount of binder is constant (a quart or a gallon)... the "What Makes Paint Glossy?" page can't be entirely correct.

Now that I know to look for "pigment volume concentration," though I find this (slightly different) formula: (Total sum by volume of all pigments + extenders in paint) / (Total sum by volume of each solid ingredient in paint) x 100%

So, flat paints must have more extenders (fillers?), and glossy paints have fewer extenders.

Going back to the "What makes paint glossy?" page, and reading that flat paints have a PVC of 40% or higher, and glossy paints have a PVC of 15% or lower, it's clear that the amount of extenders in a gallon of flat paint must amount to at least 25% of the non-solvent ingredients in the paint.

I don't how much fluid this works out to, but it's clearly too much to accomplish by means of a couple ounces of additive per can of paint.

After all this I guess I can conclude, that the best way for a store that mixes their own paints to save floor space (and reduce how much inventory they need to keep track of) would be to keep one big drum of each of gloss base and flat base, and have a machine which dispenses the desired proportion of these bases into empty cans, to produce the intermediate eggshell/satin/semigloss bases.
-- goldbb, Oct 11 2009


[goldbb] Don't the bases already contain pigment? For instance, to make the paler yellows, you start with a light base (which is essentially white paint, and contains titanium dioxide or other white pigment) and add the correct amount of yellow pigment (sometimes called tint).

That does not change your conclusion; in fact, one local paint manufacturer recommends mixing the gloss and flat versions of one of its products to produce intermediate gloss levels. (It is a specialty paint, and I'm guessing they do this precisely so they don't need to stock a range of gloss levels.)

The "what makes paint glossy" article just uses sloppy language. "pigment volume concentration (PVC), which is the comparison of the volume of pigment to the volume of binder" should read "...(PVC), which is the ratio of the volume of pigment to the total volume of solids (pigment + binder)", with the understanding that extenders are included in "pigment" in this instance.
-- spidermother, Dec 10 2010



random, halfbakery