Enlarger alignment quick test

[jstewart]

Every method I've read for checking alignment on the enlarger requires special tools or measuring distances from several points.

Somebody please tell me why this method doesn't work:

Using a grain magnifier, focus an image at its center for a relatively high magnification (i.e., the head near the top of the column.) with the lens opened wide open (e.g. f 5.6). Then move the grain magnifier toward one corner while looking into it. As you get farther away from the center, you will need to tilt the magnifier so the mirror stays somewhat perpendicular to the light path. When tilted just right, the image will fill the field of view of the magnifier. Do all four corners this way and see if any are out of focus. You need to keep the front of the magnifier base in contact with the easel surface so the eye-to-easel distance stays proportional to the length of the light path throughout the test.

Logically, seeing the grain in focus at each corner seems to suggest that the negative carrier, lens, and easel are in alignment. This is too simple not to have read about it before... what am I missing? Can the corners be in focus using this approach even tho the enlarger is misaligned such that the print will suffer?

Jim

 

[wfwhitaker]

Logically it does make sense. But where are you going to find an enlarging lens which can project an image in focus at the center and corners, especially wide open?

 

[JohnArs]

Hi

There is a much easier cheaper way put a neg in the enlarger and mesure booth long sides they sould be exactly similar in lenghs and the same to the booth short ones if this is fine all will be fine.

 

[Loose Gravel]

Some folks level everything out. With a good level, this works.

The grain focusser works fine. I've done this as a check for a long time, ever since I had a grain focusser that would work at the edges. I use a piece of unprocessed film with knife scratches in the emulsion. It makes for a very sharp, contrasty, easy to focus target. Quality enlarging lenses have fields that are flat enough to do this. I would recommend that you not run your enlarger all the way up unless this is where you use it to print. Put the enlarger in the range where you print. Columns and such are not always straight.

The other thing that works in your favor is depth-of-field. If you stop down a couple of stops, then the depth of field will help. At near 1:1 ratios, you don't have much depth, however.

 

[Phillip P. Dimor]

I take a piece of window screen, the plastic type. You know, the plastic mesh that goes in a screen door? I cut it out to size and sandwich it with two sheets of scrap glass and insert the whole thing into my enlarger. This gives me a good idea if any of the corners or sides are out of wack.

As for aligning, I've used a bubble level. I hate it. I'm amazed that any of my photographs are sharp at all.

I keep telling myself that the Versalab aligner tool is what I need but I can't spring for that much...

 

[dancqu]

A ruler and square plus pliers, screwdriver, etc, are all
that you need. Be sure a projected image is square and
sharp all corners. Dan