When photoshop cs won't allow the artistic filters to apply - what do i need to enable them?

i want to use colored pencil filter to create artistic photography, but the artistic and other filters don't light up for use, at times. i can't figure out why.When photoshop cs won't allow the artistic filters to apply - what do i need to enable them?
When you work in Photoshop it works in layers of each thing you change. To apply things like filters to the whole image, not just a layer of it, you need to 'Flatten' the image first. In the 'layer' area. Try that!When photoshop cs won't allow the artistic filters to apply - what do i need to enable them?
Also, do check the mode you are working in.. Some filters don't work in the CMYK mode... they become active only when the image you are working on is in the RGB mode..





Hope this helps :)