There are quite a variety of ways to achieve colour effects on your casts. First and possibly the easiest ways are to use pigments. The pictures above show a variety of colours that can be achieved using either dry or wet pigments. They come in a variety of colours and if instructions are followed, are very easy to use. Dry pigments have the advantage of not retarding the drying time, so you can use more product and get a deeper colour. Wet pigments on the other hand are cheaper to use as they go much further, but care must be taken as to the amount added to the mixture. Too much product will result in a very slow drying cast and in some cases it just won’t go off at all, leaving you with a sloppy mess that has to be binned. I found that following the instruction and a bit of trial and error on small amounts worked wonders.
Another good way to achieve colour is to use paint on products. These has the advantage of been able to cast as many different pieces/sets as you like at the same time, then apply the specific colour of choice to each piece. The pigments as mentioned above can be diluted with a little warm water and used as a paint product. You can also use other products to colour your cast... I found tea to be a really good way of getting a nice ivory finish, though it does take some skill and timing to get a good outcome every time. Also useful is wood stain. This comes in a good variety of colours and also gives a nice spread of colour over the whole cast, resulting in varied shading to the piece.
Colour washes are also a good way of achieving a variety of colours. This can be done using either water colours or diluted acrylics. Using this method you have the opportunity to produce a large range of colour options to offer to your customers.
Sealing Your Cast
Unless you are using acrylics to paint your cast, you will need to seal it with a product of some kind. Lacquers/varnish and glazes are available from most good craft shops. I myself use an acrylic glaze as this dries into the cast forming a tough outer coating that will not peel. It makes the cast more durable and waterproof and also helps to protect from dirt that might be acuminated when handing or being displayed. It is best to be applied in a few thin layers rather than one thick coat, as this seems to improve the setting and durability of the product.
The pictures below show what can be achieved when you use both pigments and detail painting on a cast.
Take for example pic 1 (the Birds). The original casts where colored using a light terra cotta mix to the stone powder. This gives the base coat of colour. Always allow the cast to thoroughly dry before applying any paint, otherwise it will peel off and wont adhere to the cast surface due to moisture. The bases where then painted with the red acrylic paint and allowed to dry overnight. More detail was then picked out with gold and silver metallic acrylics, this again was left for a few days to dry thoroughly. Then finally the whole piece was colour washed over with a black acrylic coat then the excess removed quickly. This leaves a small amount in all the detail of the cast giving an aged effect. I then sealed the piece with a quick thin coat of glaze to protect the cast. Finally the felt is added to the bottom using good quality craft glue.
When working on a very detailed piece and you would like to paint the whole piece in a variety of colours, I suggest using either water colours or dilute acrylic paint. This gives the piece a more translucent look and is more forgiving with edges and the overall appearance. Again you will need to seal the cast with some type of product to protect your work.