There are several gadgets from lasers to mirrors, for setting alignment. My method isn't as exact, but it's cheap. I spent quite a bit of time on the phone with a Beseler technician, and I do now have grain sharp across the print. (I switched to a glass carrier after reading Ctien's book, post exposure.) I have a 23C XL.(posted 9243 days ago)Take a negative with obvious grain structure (TMZ) and make an 11X14. Use a loupe to check the sharpness of the grain structure at each corner. If all the same, you are lucky, don't worry about alignment. On the other hand, if one side or one corner shades to fuzzy, it's probably an alignment problem. If center sharp, and corners fuzzy, that's negative flatness. (There's another issue of negative flatness. The glassless carriers most people use allow the center of the negative to be a little higher than the edges. Generally, stopping down two or three stops gives the best resolution, and the added depth of field helps with keeping the whole negative sharp. But ultimately, for optimum results, you need a glass carrier. They are a pain, because of all the surfaces to get dusty.) Alignment is a three step process, and you need a small level. I like the ones they call "torpedo" levels. The first step is a level baseboard. The enlarger should be on a firm, workbench type of support. I would work on getting that level, possibly with shim shingles that you glue in place. Once the baseboard is level, find something a little larger than the negative carrier which will fit into the negative carrier and give you a place to set the level. An 8X10 piece of glass, or even a similar piece of 1/4 inch plywood (not warped). The thumbscrew that torques down the whole assembly to the support beams should be tightened. Put the oversize "negative carrier" into the carrier and clamp it in place by putting the lever in its rear position. Place the level on the wood or glass that projects out side the negative carrier. It should be level both side to side and front to back. Note that the whole assembly can be tilted back to project on the wall if you release a catch. When the assembly swings back to verticle, it rests on a little bolt at the base of the assembly. That is the adjustment for vertical. Screw it in or out until the negative stage is level, front to back. If you have a side to side level problem, that's a little deeper. The old Beseler require that you find the two screws that hold the assembly to the piece that rides between the frames. Those holes get filed out (oval) so you can shift the assembly and retighten. The easy adjustment is the screw that the whole assembly rests on when returning from horizontal. Once the negative carrier is level to the baseboard, move on the the lens board. I put the level right against the lens, again checking front to back and side to side. Directly below the lens board, toward the rear, is a little knurled screw, typically with two white lines that line up. When you loosen that screw, you can twist the lens board from side to side. Set to level and tighten. Finally, check the front to back level of the lens. Here its a little tricky. This angle is adjusted by shims under the same gnarly screw that set the side to side. You will probably find a washer under that screw. You need a thinner or thicker washer to vary the tilt of the assembly. Any shim stock works, even layers of cardboard. As you can see, its not as easy as turning a few screws. The new Beselers have been designed for easier alignment. Once set, it should stay in place for a while, but especially with a new setup of an old model, I would check it out. Light source is a whole other issue. I have replaced the condensers with the ARisto cold light head.