Quality of Light

[jp]

I think that enlarger head has two lamps in it. The lamps get dim over time. The dicro mirrors get dirty. That affects quantity of light, but little else. You should keep a spare lamp; that'll tell you what you need to re-order.

You may need to clean the lens to increase contrast; make sure it's not hazy. You may need some extra contrast. Maybe the film carrier slot is leaking light into the darkroom and fogging paper during exposure? Lotsa possibilities. Maybe your developer went weak over the few weeks since you did the contact prints?

[Paul Hoyt]

I would be willing to bet your enlargement has more contrast than your contact print. In a contact print, all the light that passes through the negative strikes the print; none is lost. When you enlarge, some of the light exiting the negative is bent by silver grains and fails to strike the print. This happens at the higher densities of the negative and with less light exposing the enlargement at the higher densities, the contrast is increased. If you match the clouds in the enlargement to the clouds in the contact print, the lower densities will have received more exposure than the contact print and are much lower in tone. You will need to decrease the contrast of your enlargement to get closer to the contract print. Different light sources (condenser, diffusion, point source) are not equal and will require different changes in contrast for enlargements. I have needed to make changes in contrast when making enlargements from an 8X10 enlargement to a 16X20 enlargement.