If you create a large painting and save it as an ArtRage painting file (*.ptg) when you re-open it we 'zoom' the painting so all of it is visible on your screen. If you are opening your 4000 x 3000 painting in a 1024 x 768 window, it will be zoomed out to around 23% to fit all of the painting inside that window.
The only Export format that correctly supports your DPI setting is Photoshop PSD. All other export formats (jpg, png, bmp etc) discard the paintings DPI setting and default to your computers screen DPI (depending on what viewing application you're using)
Note that the DPI settings are only important when it comes to printing the painting. DPI makes no difference on your screen. A 4000 x 3000 pixel image at 300 DPI gives exactly the same amount of detail on your screen as a 4000 x 3000 image at 72DPI.
When you're doing your painting, are you painting over the entire canvas? If you have a 4000 x 3000 painting, zoomed to 100% on a 1024 x 768 display, you're only able to see a small portion of your canvas. If you only paint in the area you can see, and dont move the canvas around inside ArtRage to access other areas of your painting (or zoom out to see the whole canvas) you will only be painting on a small area of the canvas.
If you only want to paint at 100% in the visible area of your window, choose a smaller canvas size. There is a button in the New File panel to set your canvas size to the size of your window.
AndyRage's mantra for graphics engine code:
"Sure - how hard can it be?"