I don't own a 23CII, but a 45MXT. Is there w away to raise and lower the head between the negative stage? Your head might be too close to your negative. If you can raise the head away from the negative stage, you might get even coverage on your negative. Prof Pix may be right also about cosine fourth law of illumination falloff. Try tilting your meter towards the lens and you might get a brighter reading. To me, it's not a big deal since I burn in light areas of prints anyway.