Response to Uneven processing?

The light fall off you describe can be caused by a number of different things. The suggestions above are good and should be checked. Here are a couple of other things for you to consider as well: If you are shooting with a wide-angle lens on camera and the camera is relatively close to the copy work, there will be light fall off due to the relatively large distance difference from the lens to the center and edges of the film, respectively. This problem can be solved by using a longer focal length lens and moving the camera back. If this is not possible, a center filter would be necessary to compensate for this effect. The same problem applies to the enlarger/lens set up. Make sure your lens not only has enough coverage for the neg, but that the enlarger head is not too close to the baseboard causing the distance from lens to edge to be significatly greater than the lens to center distance. The same applies for the lens to negative distances. In general, use the longest focal length lens possible to minimize the fall off at the edges on both camera and enlarger. Also, be sure to check your enlarger light source to make sure you have even illumination of the negative. Condenser heads are notorious for having hot spots in the center if adjusted improperly, and even the best cold-light heads can be uneven, especially if the diffuser is close to the same size as the negative. Processing is also a consideration, especially if you tray process by hand. If you do, make sure that when you push a sheet down into the developer solution, you are giving the center of the sheet adequate agitation. Fingers can block the flow of developer across the center thus giving the edges of the film more agitation. Also, pushing down too fast or too slowly can change the amount of relative agitation at the edges of the film due to swirling of the solution at the edges which doesn't affect the center of the film. Hope this helps, ;^D)

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