What is excessive when using an image map shader?

[Largent]

I'm trying to crank out my first hurricane and from what I've gathered on the forums I need a high res image of a hurricane to use as an image map shader. I have three questions:

Is one image enough or should I have multiple images for multiple layers of clouds?
Do I want the image, once its photoshopped, to be black and white or have shades of gray?
How big is too big? Currently I'm working with an image 5600X7200.

[freelancah]

You need something similiar like this. f.e. 6000x6000. You can use the color adjust shader to change the levels to the desired direction..

[cyphyr]

Its all going to depend on your point of view. Obviously if your looking at the hurricane from far away you'll need less detail. If you use greyscale images you can feed them through a colour adjust shader before the blend shader input, thus one image can be adjusted to several layers of cloud. Bigger is better but it is the mask so as long as its within your memory limitations that should not be a problem. nvseal is the planetary cloud master (that's his image on the TG loader), maybe he will chime in.
Hope this helps
Richard

[Largent]

From what I gather its sounds like the image will be fine as long as I upload it into PS, grayscale it and up the contrast a bit. The image is over water so I can achieve an image like the example posted. It also sounds like its not too big. This is all great.

Any general advice or tips while were on the subject?