I have a negative that is underexposed. On the light box, in transmission, the negative appears hopelessly thin. However when I hold it up to an oblique light source with a black background, I am able to see a positive image with a good amount of detail. I call this the dark field image. However when I try to print it, I am unable to dig out an image that comes close to the dark field image. This upsets me because the dark field image is quite serviceable. I possibly could scan the negative because I have heard that scanning can extract more detail from underexposed negatives than printing, but I don't see why that should be the case.
Is a diffusion enlarger better than condenser for digging detail out of thin negatives?
Could I copy this negative back to film a couple times? Is chemical intensification an option that will help?