Never Ending Enlarger Re-Alignment

Most articles that talk about enlarger alignment tell you how to do it, but don’t explain how it can be a never ending battle.  For me and my two Omega D5s, the mechanisms that throw my enlarger out of alignment are drop-away baseboard tabletops and different negative carriers.

Baseboard Alignment Error

My enlarger is bolted to the wall and the table is mounted below it.  To make larger prints or for more extreme cropping, I can remove the upper tabletop and project down to a lower table top.  I can also remove the lower tabletop and project all the way to the floor.

Removable Tabletops (projection surfaces)

Both of my enlargers are configured similarly.  The tabletops are 3/4″ plywood supported on three or four sides and they are not perfectly parallel, although they are close.  For most routine printing, they don’t introduce enough error to worry about, but when I am being very critical and exposing at wide apertures to avoid diffraction issues, I will align the enlarger for the specific configuration in use.

Negative Carrier Alignment Error

Omega has two main types of negative carrier.  First is the two-piece sandwich and second is the spring loaded Raid Shift carrier.

Rapid Shift (top row) and sandwich style (bottom row)

Each of these carriers can be further divided into glass and glassless.  I use glass carriers exclusively.  In theory, when the Omega lamp house is lowered onto these carriers, they are compressed perfectly flat eliminating any chance of injecting alignment error.  The reality is different. I align my enlargers using a laser alignment tool.  Once I have the enlarger aligned for one carrier, I would expect all my other carriers to behave the same.  They do not.  The rivets in these carriers warp the metal slightly.  The spring tabs at the rear of the Rapid Shift carriers are also cable of preventing the two haves from lying perfectly flat.

Finally, the glass thickness may not be precisely correct for the film thickness, causing a slight bowing of the carrier when the lamphouse is lowered onto it.  My carriers have a mix of original equipment clear and anti-Newton glass from Omega, Focal Point, and some that came installed in carriers purchased from ebay.

What I have found is that my laser alignment tool shows that aligning with one carrier, does not always mean all carriers will be in alignment.  Furthermore, lowering the lamphouse onto the carrier may also also alter the alignment.  Granted, the shift is not great, but it is enough to shake my confidence that I will get corner-to-corner sharpness in a large print at wide apertures.  Large, for me, is 16″ x 20″ or 20″ x 24″.

While there is no easy fix to this dilemma, anyone who uses a view camera knows that lens adjustments (swings and tilts) can be used to match a plane of focus to a non-parallel film plane using the Scheimpflug Principle.  Stated another way, the lens plane can be adjusted to accommodate any errors in alignment between the enlarger film plane and the easel.  Besseler did exactly that when they offered a lens board called a Bes-Align.  It has three adjustment screws to allow an enlarger lens position to be adjusted in a way that can be used to accommodate a misalignment between film and easel.

Bes-Align

The adjustable lens board can be used in conjunction with a Micromega or Peak grain focuser to tweak the lens plane as required to ensure the corners the image projected onto the easel are in focus.  It provides a quick way to fine tune enlarger alignment to compensate for errors introduced by different negative holders or baseboard (table top) configurations.

I made a version of the Bes-Align to fit an Omega D5 years ago.  I simply attached a lens mounting plate to an Omega lens board using three machine screws with an 3/16 inch layer of black foam between the plate and the lens board.  The foam serves as a light seal and as a spring to act against the three adjustment screws.

My copy of the Besseler Bes-Align adjustable lens board to fit an Omega D5 enlarger.

My copy of the Be-Align was functional, but I wanted something deeper that would accommodate the rear extension of my El-Nikkor lenses, so I decided to add a spacer and make it more rigid with actual springs rather than relying on the resilience of the foam rubber spacer.

Improvements included springs and a 1/4″ spacer.

I drilled out the threaded holes in the original design lens board in favor of threading new holes in the much thicker spacer.

The adjustment range of the new design will permit perspective control on architectural pictures.

I found cheap springs at the local home improvement store and cut them to length with a Dremel tool.

The springs are fairly stiff and the adjustment screws go most of the way through the 1/4″ space making the assembly quite rigid.

 

The hole in the stock Omega lens board is considerably larger than the lens mounting hole.

The rear of the lens extends up into the gap between the lens mounting plate and the Omega lens board.

I used soft black foam shelf liner material to seal against leaks. I cut the strips, roughed up the glue surfaces with sand paper, and then epoxied them to the edges of the 1/4″ spacer.

Fitting the light seal strips before actually gluing them.

I sanded, primed, and painted the pieces to further reduce light leakage and reflections. I did not paint the surfaces that were to be glued.

Spring placement and final assembly of the pieces.

As you can see, I ultimately settled on using Phillips head adjustment screws. I tested the 40 mm lens first to make sure the lens wasn’t too far away from the film plane to focus.

This shows how far back the lens extends toward the rear, but I will easily be able to slide the lens board out of the enlarger without having to unscrew the lens.

The 150 mm lens is the heaviest of my lenses, but will be held securely enough to keep it from moving when I change aperture settings.

The final product installed on the enlarger with my under-lens filter holder positioned under it.

Laser Enlarger Alignment

If you’ve been involved in darkroom photography very long, you already know that corner-to-corner sharpness of a print made using an enlarger requires a properly aligned enlarger.  That simply means that the negative, lens board, and baseboard are all parallel to each other.  Tools are available to help verify and adjust the alignment of your enlarger.

I’ve tried enlarger alignment using bubble levels and a clumsy, although workable, DIY version of the ZIg-Align.

DIY mirror alignment system based on Zig-Align (although not as good).

In my opinion, laser alignment tools are the easiest to use, easiest to see, and provide ample precision.  “Easy” is important if you intend to make alignment verification part of your routine.  The Versalab Parallel tool looks like a great solution, but it costs $200+.

The laser tool I finally settled on consists of a 3D printed platform to hold a low cost laser sight.  If you have access to a 3D printer, the design created by Larry Gebhardt at Tripping Through the Dark is the best low cost solution for quick and easy enlarger alignment.  Below are pictures of the one I printed from the file supplied at Thingiverse.  I got the laser sight on Amazon for $10.99, but Amazon no longer lists it.  They are, however sold new on ebay for under $10.

CAUTION!  BE CAREFUL NOT TO SHINE THE BEAM IN ANYONE’S EYES!

I added the little square piece of post-it note to the top to make it easier to read when the beam is reflected almost directly back into itself.

Laser Tool Calibration

The laser alignment tool must be calibrated to be sure he beam is perfectly perpendicular to the base.  To do this, you simply set the tool on a horizontal flat surface pointing up at the ceiling, turn on the bean, and adjust the two set screws until the point of light on the ceiling remains stationary when you rotate the tool in place.  I use the center head from a combination square to keep the tool in place as I rotate it, but anything with a L-shape can be used. If the tool is not calibrated when you rotate it, it will trace a circle on the ceiling which means the beam is not perfectly perpendicular to the table.

Calibration of the tool requires you to be able to rotate it on a flat horizontal surface without it moving.

I tacked a 1″ paper target to the ceiling above my darkroom counter top as a reference point.  Once you have it adjusted, it stays put almost forever.

I tacked a paper target 1″ in diameter to the ceiling as a reference point.

Using the Laser Alignment Tool

To use the alignment tool, you simply place it on the baseboard or easel below your enlarger so the beam shines directly up through the lens mounting hole.  You align the negative stage by placing a piece of glass where the negative carrier normally goes and adjust it until the beam reflects off the glass directly hack down into the center of the laser.  A glass type negative carrier can, of course, be used instead of a separate piece of glass.  I put a piece of black paper on top of the glass to prevent any spurious reflections (e.g. from a condenser lens or mixing chamber above the glass).

The lens stage is aligned in a similar manner.  Instead of attaching the glass, you can simply screw a flat filter onto the front of the lens.  I once tried using a 49mm filter with a cheap ebay adapter to fit the 40.5 mm threads on the lens, but the adapter thread was apparently a different pitch because it didn’t screw all the way in and when I rotated the lens (as you can do with El-Nikkors), the reflected beam moved in a circle indicating that the filter was not perpendicular to the lens axis.  When I tried a 52mm filter with a cheap 52 to 40.5 mm ebay adapter, it worked fine.

If you don’t have a filter, you have to find a way to attach the glass to the lens stage or the front of the lens.  I’ve done this using a rubber band to attach a piece of 4″ x 5″ picture frame glass to a lens board with a few lens spacers installed.

To align the lens stage, I attach a 4″ x 5″ piece of glass to a lens board with a rubber band.

Note the lens spacers above the glass to make sure the glass is registered to the same plane as the lens. The tape protects the rubber band from the sharp edges of the glass, but must not come between the glass and the lens board.

Alignment Sequence

Since adjustment of the forward and backwards tilt of the lens stage on the Omaga D5 seems to require adjusting the tilt of the entire carriage, it is best to align the lens stage before the negative stage.   In other words, adjusting the eccentric rods to affect the forwards/backwards tilt of the lens stage will also affect the tilt of the negative carrier.

Rechecking Alignment

Once you have the enlarger aligned, it is a fairly simple matter to check the alignment before a printing session.  It is also easy to verify alignment after setting up the enlarger for an important print that you want to be perfect.  You can very easily experiment to see what factors may affect the alignment.  For example, does the alignment change when you raise or lower the head?  If you use glass carriers, see if different carriers affect the alignment.  Same is true of different easels or if you have an adjustable table.