I've been doing some printing tests , I take the same picture at iso 200 , 400, 800 and 1600 and print them all out [ at a lab ] 8X12 to see what the difference is in real prints . I did it again with my D70S at high iso and also compared a photoshop " jpeg max quality " [ 3400kb]to a " jpeg high quality " [ 790kb] printout . Now I want to do a comparison of the cameras jpeg fine vs normal vs basic but was wondering what type of subject would best bring out the 'worst' possible scenario ? [ as with the iso tests I took a picture out the lounge window with the inside of the room also showing underexposed areas to emphasize the noise ] . Since the jpeg compression applies to areas of colour would the best test be with a multi-coloured picture with large and small patches of colour ?