And what are you using for sealer?

For me,there are two sealers for masks,both of them containing xylene,a toxic element,but it gives a hell of a seal!I use glaze and clear,which gives a slight shine.We're real happy with the glaze,part.on terra cotta colouring.
I have a two part epoxy sealer that cleans up with water and is food safe,so I would use this on indoor fountains(the cats think fountains are cool drink dishes!)
Or,were you asking Tango...?

Been outta' town for a while, sorry I could not get back quicker. While sealers generally help colors appear brighter and do help a little to prevent fading, their main function is to limit water penetration. But unless they have an anti-UV ingredient , they really don't help all that much. The main determinent is the stability of the color product itself. Some are rated as totally stable while other fall into the "transient" category. Most oxide-based and acid etch colors will last just about indefinitely. Organic dyes and most synthetics are quite unstable and can go away very quickly. Another consideration is the density of the medium (concrete, cement, 'Tufa). The denser the material that the color is in, the longer it lasts.

Try searching this forum for something like "color charts"...it is a list of color mediums and their basic properties that I posted about a year ago and someone was kind enough to create a web page for. Hope it's still around.

Also, regarding sealers, the water bourne are more ecofriendly, but do not have anything near the staying power of the commercial solvent-based materials...many of which have a twenty-year rating, which, at this time, is considered pretty much the industry standard for longevity.

Best of luck

I'd like to add that all products marketed as concrete pigments are not created equal.
Be careful of synthetics, some fade badly.
And the quality difference can be huge.
There is a company called Butler in the US that claims to sell concrete pigments but they are mostly crap. But crafters who don't know any better buy the stuff and then wonder why the color fades out.

Even something as simple as black.
I have black from two different companies.
You add 10% of one of them you get coal black concrete. REAL black.
10% of the other brand gives dark gray. In fact I doubt it would ever give pure black.
Some pigments are no deal at all.
I got my list of the good stuff from a couple handons brick laying companies and the batch plant foreman.
The best way to buy pigments is read the spec sheet very closely or you could be very disapointed later on.

And forget about going by price, with the exception of Blue the really good pigments sell cheaper than the crap because they are sold in vast amounts to bulk plants and contractors.

When I use a xylene based sealer it 'sets' the color and the concrete.
So when you spray the pot with water or water the plants the colors do not change when wet.
Using the water base product you get spots that darken up when the pot gets wet.
I hate xylene and don't know how I'm going to use these products indoors during the winter.
I'm considering a littls paint booth with an exhaust fan in the wall to suck the fumes outside.
Water based sealers may be good for concrete floors but suck when the finish has to be really good kike in a nice colored pot or mask.
So I expect I'l be spending most of the winter in a xylene buzz.

Thanks,Tango for your elucidation.We put a notice to our buyers that the colours,like us,will get more faded with time in the sun and rain.Our intrinsics(base colours)as you say,won't fade,and it's an unknown but unlikely that the metal based paints (copper and iron so far,from Modern Masters)will do anything other than become more rusted or patinaed with exposure.Which in this case is a good thing!
Cheers from here

Tufaenough, I've sealed over 50,000m2 with Xylene based product, and I ALWAYS use a rubber mask, with two cartridges rated for solvent vapours. As you are probably already aware, Xylene is one of the nastiest chemicals around, and can damage almost every tissue in the body.
I still go outside and check myself every now and then while working. The thing is, you don't know Xylene has got you until it has well and truly got you.
For larger jobs, you should use a self-contained mask/breathing apparatus.
As has already been said,there are also available, penetrating sealers which do not alter the appearance of the concrete/stone, and are designed to stop water penetration, but allow vapour to escape from inside to outside. The ones I have used are usually also spirit based. The good ones are an excellent product.
When looking for a gas/vapour mask, buy a good one, not a cheapie, they're useless. Also, when you've finished your work, remove the cartridges from the mask and store them in a sealed plastic bag.
Hope you avoid the 'Xylene buzz,'
Slate

Roger the "Buzz" factor. It is caused by brain cells dying...that should give a clue as to how serious it is. By the way...they don't grow back, either so be careful. You might need then later. For the best info on any suspect product, look online at the manufacturers websites and read and heed the MSDS (Manufacturers Safety Data Sheets) info that they are required to post by law. Some of them make for a scarier read that anything Stephen King ever wrote.

Rick --- Found a link to the page that has the color charts. Click then scroll down to find it as a Word doc.

Hope it helps.

Here is a link that might be useful: Color Chart discussion page...