The eye is most sensitive to yellow light. Yellow filters blue. Photo papers are most sensitive to blue. So, a negative can have a lot of yellow dye (stain), we look through it and it looks like the density is low. The photo paper looks through it and it looks dense.(posted 8793 days ago)This is the "murky, low contrast, unprintiable" appearance of pyro developed negatives. I suspect if you looked at the negative through a blue filter, it would look more to they eye as the paper sees it. But they eye is not very sensitive to blue light.