Lars Holtgrewe , Oct 18, 2010; 09:08 p.m.
A few pointers to help you on your way:
The aperture of the enlarging lens is largely used tocontrol the printing time. It works the same as your aperture in your camera; a larger aperture (smaller f-stop), the more light, a smaller aperture (larger f-stop), the less light. Generally most lenses will start to perform best stopped down 2 stops from wide open.
A good procedure to follow for making a starting test strip is this:
1. Set or insert a #2 filter and stop the lens down 2 stops from wide open, insert the negative and adjust the enlarger head height to project the approximate desired paper size
2. Place the test strip (I usually use ~1"x8" strips cut from an 8"x10" sheet) in an area that will allow you to see variations in time (light and dark values vary as little as possible). In a landscape, the horizon line is often a good place to put the test strip.
3. Expose the strip in intervals. Start with 5,10,15, etc. seconds.
4. Develop and stop for normal times, fix for 1 minute (30 seconds if RC paper).
If the entire strip is too light increase exposure time (10,20,30,...). If the entire strip is too dark decrease exposure time (1,2,3,...)
This is where the aperture of the lens can come into play. Often you will want to stop the lens down further to extend the printing time. Each full stop smaller is 2x the printing time. This would turn your (1,2,3,...) time into (2,4,6,...) and allow easier burning/dodging in the future.
5. Once you have a test strip that goes from too light to too dark, you have a test strip you can evaluate.
6. Find the time in which the highlights have just barely discernible details; this is your starting printing time.
7. Place a full sheet under the enlarger and expose at the time found from the test strip and evaluate. Ensure the highlights are correct and judge contrast.
8. Now you may adjust the contrast by changing the filter. If large changes in contrast are required you may need to change the exposure time. Do another test strip to find your highlights.
9. Only at this point may you consider dodging/burning. I will leave that topic for future discussion.
That will get you started, and to answer a few other questions as briefly as possible:
Exposure time determines overall how light/dark the image is. Contrast/filters determine the range of values from white to black (number of gray shades).
Check the negative to ensure there is anything to print in the mirrors before attempting to burn in. It is very possible those highlights were "blown out" and there will be nothing there to print. If it is an otherwise good negative, this could be hidden with minor amounts of spotting if the area is small. If it is a large area, and there is nothing there to print, abandon the negative.