Aligning an Enlarger

[fotch]

........
The problem is that in order to use this wonderful device, one has to be able to look trough the hole, so the enlarger-head must be removed. This causes a change in the top weight of the whole construction. Doing this, I have seen an important change in the inclination angle of my Omega D3. So, I guessed that the alignment whit-out the head will not be the seam as with the head.....

Why not just raise the head like when inserting a negative holder and use a small dental mirror to reflect back at a 90 degree angle to the viewer?

 

[TimVermont]

If you've got multipe enlargers to align

I have to admit the Versalab is expensive, but I have to align 18 enlargers at two different schools, so I love how easy and quick it is to use.

Amen. And I'll add to it that the process is such that the enlarger is in the same state that it will be used in, i.e. negative gate closed, lamp head in place, etc. This may not be the case with other methods, and the weight of lamp heads, etc. in the wrong place can have considerable effect and frustrate the user.

 

[clayne]

I use a Versalab. Works fast and quick - although the rubberband method for the glass reflector annoys me and is too fiddly. Aside from that issue it's great.

 

[dancqu]

Now I'm Repeating Myself

I align the enlarger with the Versalab but double check
(paranoid?) with a Focus Finder. That way I know it is
both correctly aligned and sharp corner to corner.
The Versalab is one (very accurate) way of
doing it – but not the only one Martin

OK, so trusting to the Versalab's indication of a correct
alignment you are satisfied that the planes of the easel
and negative and the plane perpendicular to the optical
axis are all parallel. You are not wholly trusting though
so check with a focus finder.

Now I repeat; a projected image may be sharp, corners
and center, even if the enlarger is not aligned. A check
for focus is not assurance of correct alignment.

Checking with a square will provides greater assurance.
My previous post describes the procedure. The method
does assume the source of the projected image to
have all corners be of 90 degrees.

Either way, we must be trusting. A square or any
right angled item may be used. When ready to
print I've made checks in no time using a
single size easel. Dan

 

[clayne]

Now I repeat; a projected image may be sharp, corners
and center, even if the enlarger is not aligned. A check
for focus is not assurance of correct alignment.

Dan, what enlarger situation is even going to cause this anomaly? If the baseboard surface is flat and the lens is of sane design (and negative carrier accurately aligned), how will the Versalab not catch all issues? One can even use the laser to check the carrier directly.

 

[Jim Jones]

An image may be sharp four corners and center with
the enlarger quite out of alignment. You've heard of
Scheimpflug.

The method I've described assures correct alignment.
The method assumes the projected image to be
composed of four 90 degree angles.

With the image focused as well as it might be, test
three of the four corners with a square for a true 90
degrees. If the three measure true then the enlarger
is aligned; the image will be sharp corners and center.

No alignment tool other than a square is needed. Dan

Lack of sharpness is more critical than perspective errors caused by misapplication of the Scheimpflug principle. Using a square is a good second check, though. Not all of my negative carriers have perfectly square apertures.

 

[Philippe-Georges]

Why not just raise the head like when inserting a negative holder and use a small dental mirror to reflect back at a 90 degree angle to the viewer?

Dear Fotch,

Yes, this is a possibility, but the Hasselblad mirror, even the small one, is still to thick (about 2 cm) to insert an extra small mirror between the bellows frame and the lowest condenser.
But, I have to admit that I never tried your suggestion.

Philippe

 

[dancqu]

The Cause of the Anomaly?

Dan, what enlarger situation is even going to cause this anomaly?
If the baseboard surface is flat and the lens is of sane design
(and negative carrier accurately aligned), how will the
Versalab not catch all issues? One can even use
the laser to check the carrier directly.

The anomaly; sharp all over but not aligned. One cause might
be correcting, without an alignment, for an all corner and center
sharp image. A second cause might be an alignment followed
by a four corner and center focus correction.

The Versalab is a tool designed to facilitate alignments.
It is of sound design. It projects a beam of light upwards
at 90 degree. That beam strikes one then later another
mirror. If the mirrors are perpendicular to the optical
axis the beam is reflected back upon itself. Three
entirely parallel planes are the result; the easel,
the plane perpendicular to the optical axis at
the lens, and the negative carrier.

Certain mechanical matters concerning an enlarger's
construction allow me some reservations. I've training
as a machinist and am likely more aware than most of
tolerances and fit. Some enlargers must be more
amenable to exact alignments than others. Dan

 

[BetterSense]

How important is this anyway? I never align the front and back standards on my view camera with a laser; why should it matter as long as the image on the baseboard looks square and sharp? I don't see why I should even measure it; human eyes can tell with remarkable accuracy if it doesn't look square. If it looks square, it's square enough. Must the final print only be viewed perfectly on axis? If not, it won't be appear perfectly square.....

 

[Philippe-Georges]

How important is this anyway? I never align the front and back standards on my view camera with a laser; why should it matter as long as the image on the baseboard looks square and sharp? I don't see why I should even measure it; human eyes can tell with remarkable accuracy if it doesn't look square. If it looks square, it's square enough. Must the final print only be viewed perfectly on axis? If not, it won't be appear perfectly square.....

Yes, BetterSens, as long as it looks good in might be good.

But, there are different situations with different needs and conditions. This is why, when a camera or an enlarger is made, the manufacturer is always fine tuning and adjusting in order to deliver a perfect apparatus.
If, afterwards, their is an certain 'evolution', then it is up to the user to decide what happens. If you are happy with you gear, then please do stay happy. Others want their stuff to be aligned or fixed or modified, what ever it might be.
There is nothing wrong with either of these.

Good pictures can be made with a desalignend camera, and printed with an even more desalignend enlarger and look splendid!

There are different reasons why aligning might be important.

This thread is about aligning, an other one might be about 'unaligning', why not?

Philippe

 

[ic-racer]

Quote:
Originally Posted by dancqu
Now I repeat; a projected image may be sharp, corners
and center, even if the enlarger is not aligned. A check
for focus is not assurance of correct alignment.

Dan, what enlarger situation is even going to cause this anomaly? If the baseboard surface is flat and the lens is of sane design (and negative carrier accurately aligned), how will the Versalab not catch all issues? One can even use the laser to check the carrier directly.

Edge-to-edge and corner-to-corner sharpness is possible with the enlarger aligned as shown.

 

[Martin Aislabie]

Edge-to-edge and corner-to-corner sharpness is possible with the enlarger aligned as shown.

But the Versalab will pick up both the mis-aligned lens board and negative carrier.

Obviously, as with any moving parts there are tolerances, so precisely aligning the Carrier and the Lens then moving them means you can virtually guarantee that they are no longer perfectly aligned - but I checked both my Head and Lens Stage up and down the column and there was very little variation.

The variations I saw meant the stages were within 0.05deg of parallel - which is close enough for me

Martin

 

[ic-racer]

At least for me it comes down to owning both the expensive grain focuser that can visualize the edges and a method of establishing parallel planes.

OT: I was just shooting a bridge in 8x10 the other day and I did not have enough coverage for front rise. So, I just pointed the camera up. I'm going to setup my enlarger like those pictures and see how easy/hard it is to correct the converging lines that way. I suspect it might be harder than it looks. I suspect harder than the two seconds it take to raise the front standard on the camera when taking the picture.

 

[dancqu]

A VERY Graphic Demonstration

Edge-to-edge and corner-to-corner sharpness
is possible with the enlarger aligned as shown.

Converging parallels are brought parallel with such
an arrangement. The negative is actually more greatly
enlarged as it approaches nearer the lens. To maintain
focus the easel is tilted. Your rectangular negative will
project as a trapezoid. Some cropping will be needed.

I've a negative now in the enlarger which needs
every bit printed. So, no distortion of it's
projection is permissible.

I check with a square the projected image of the
carrier and/or negative. If the image tests square
then the enlarger is aligned and I know all points
within the image plane are sharp. To mess with
the focus after the image's testing for square
would only introduce distortion. Dan

 

[clayne]

Versalab or not, how would just looking at the situations above one not notice that it's obviously misaligned for a standard enlargement? These are pathological examples, guys. The VLab and other similar laser alignment tools work fast and quite well for what 99.99999% printers will need them for.

 

[R W Penn]

tAKE BLACK NEGATIVE USE SAND PAPER PROJECT ON BASEBOARD AT WIDE OPEN LENS ADJ FOR SHARP IMAGE AS NEEDED.

 

[hoojammyflip]

Which planes matter

I am pretty certain that there are a couple of ideas which help here. I am concerning myself with this as I have just picked up a Philips PCS 2000 (LPL) which has no alignment options. The lens carrier is a plastic mount supported at the rear which looks flimsy. Philips are no slackers when it comes to technicalities, so I am thinking there must be rationale behind this decision to cut corners on the lens mount but not on the very rigid base plate, vertical arm and head connection.

Obviously, it helps if the planes of image, object and lens are identical. However, due to Snells law regarding refraction of light rays being related to Sin(x) and Sin(x) being nearly equal to x for small x, I think I am right in saying that if the lens is slightly out it won't matter as much as if the object and image planes are out of kilter. [I say this because the increase of angle of incidence on one side of the lens will be equalled and opposed on the other side of the lens on a ray leaving the lens, as long as the angles involved are small, with this being particularly effective at the middle of the lens, thus cancelling out any deviation away from the correct plane]

Regarding the negative and base plate (object and image planes), the effect of not having them parallel would be that the distance varies from the object to the image. Therefore, only one region on the base plate will be focussed perfectly. However, by stopping down the enlarger lens, the depth of field is increased, in the same way it is increased when taking photos in the first place. This should allow for some lee way in alignment. It also suggests that longer focal length enlarger lenses, with shallower depth of field, require better alignment, and would be a reason for going with shorter lenses.

Just some ideas.

 

[clayne]

jammy: Definitely some good ideas and observations thrown out there.

I can tell you that having a lens mounted even slightly out of whack with everything else parallel seems to cause much frustration with sharpness and image quality. I once mounted my APO-N 50mm on my Kaiser using the lens mount adapter upside-down (one side is beveled, the other is flat). The adapter is pushed upwards by a spring pin system (which is also the lockout for lens removal/insertion from the enlarger). With the plate flipped it allowed the beveled portion to meet the top mounting plate rather than the normal flat portion. Obviously the lens was crooked at micro level - and as a result I could only achieve field sharpness at the grain level by stopping down to f/11 or more. Versalab also checked out fine with the enlarger itself being suitably aligned to the easel.

Eventually I figured out what the issue was, but it was very annoying to track down and the difference was quite apparent once I rectified the situation.

 

[Ronald Moravec]

a SQUARE PROJECTION IS ONLY FOR NEG/BASE ALLIGNMENT. The lens needs to be aligned also. They vary all over the map except for Leica ones.

I just put my long mirror Peak in the far edges and align with the lens full open. If you have sharp grain in all four corners and center, that is a good as it gets.

The short mirror will not get into the corners.