**Miss Nancy**: It's diffucult to relate to times when using Maxwell because it is so hardware dependant for reasonable render times. I use it on my aging Pentium 4 machine and generally for a modest sized image (800/1000) I would expect the render to take some time to get to sample level 16 (16 I feel is when image noise is, or should be, to the point it is not very noticable). If by then the noise hasn't really gone then it's time to call it a day and find out what's causing the noise problem!

You also need to consider the environment being rendered. Closed interiors always take far longer to become noise free than outdoor ones using sunlight. Try to avoid using too many light emitters and white (rgb: 255/255/255) materials. The best defined caustics come from using small, high powered light emitter/s. Maxwell is based on physical 'real world' properties and a good photography book comes in very useful with Maxwell!

For some dielectric materials a coating layer controlled with a gradeated texture can give some nice surface colour variations withou the decrease in render times that happens when dispersion is activated. The preview image I done earlier shows a glass material with a coating.