Enlarging - Depth of field? Slightly crooked baseboard

larfe said:

Well of course, this is however a rather clunky hit and miss manner of aligning a "precision" machine... same goes for lens stage etc

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No, lens stage to film is vital. Baseboard is less critical.

Jim Jones said:

Vaughn said: ↑
Align the enlarger optical system with the baseboard?
Larfe said:
How? The column is directly bolted to the board

Every enlarger I ever used would let me loosen the bolts, slide shims between the column and baseboard, tighten the bolts, and check for alignment. Repeat until the alignment is good.

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Yes. There are some enlarger benches when the enlarger baseboard is removed, allow enlargement below the enlarger if extra distance is needed between the lens and easel.

zischga said:

Hi all,

Today I built myself a baseboard for my Durst M605 enlarger, because the seller of the enlarger did not have the original baseboard anymore.
I used 2 3/4'' plywood screwed together, unfortunately it is not perfectly flat.
It is not warped a lot, maybe 3mm over the whole length of the baseboard.

Does anyone know, if these will have an effect on the sharpness of my prints?
I will probably print 8x10'' with f8 mostly and do not plan to use the open aperture.

Now I'm wondering, if this will still be within the Depth of field, using aperture f8.

Advice would be greatly appreciated.

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Nothing to worry about but if you feel the need go ahead and improve what you've got.

You can experiment and prove it to yourself by intentionally tipping the easel. Shim the easel (say with a quarter or nickel) to make it intentionally out of level and then use your grain focuser to check for problems. You'll probably find little to worry you. I've shimmed my easel quite a bit to correct perspective and unless I'm quite aggressive with it there is no impact on the sharpness of the print.

I'm baffled at the responses so far. Really, anyone with a smidgen of woodworking experience knows how to make a piece of wood flat... plane and sand and check with a straight edge. 3mm shouldn't be too hard to sand/plane down. Then add a nice coat of finish (yellow paint is nice for baseboards; it is "safe") and you've got it.

Although 3mm isn't much, keep in mind that moving the baseboard away from parallel to the negative will affect the image. I shim my baseboard and tilt the lens to make small corrections for parallel lines in the image that weren't rendered exactly right in the negative due to imprecise camera adjustments, etc. The image depth-of-focus at the baseboard is surprisingly large, so focus itself isn't really a big issue; still I'd plane the thing flat.

Best,

Doremus

Doremus Scudder said:

I'm baffled at the responses so far. Really, anyone with a smidgen of woodworking experience knows how to make a piece of wood flat... plane and sand and check with a straight edge.

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Running a planer over plywood can be very challenging. Plus, OP would likely have to buy the tools. Much easier solution is to find a kitchen supplier and see if they have any laminate countertop cutoffs he could have.

Tony-S said:

Running a planer over plywood can be very challenging. Plus, OP would likely have to buy the tools. Much easier solution is to find a kitchen supplier and see if they have any laminate countertop cutoffs he could have.

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That would be an elegant solution; probably better than my suggestion. Still, finding high spots with a straight edge and hitting them with the bench plane or sanding block shouldn't be all that difficult, assuming one has the tools already.

Thanks for all the replies! I didn't get to print with this setup yet, but I mounted a negative in the carrier and set the head to the highest position.
After that I checked as much of the 43cmx43cm projection with my grain focuser as I could.
The roughly 30x30cm that I could inspect are perfectly in focus, meaning I can see the grain at open aperture (f4,7).

I will make a practical test as soon as I make my next darkroom session, with a 40x40cm landscape print, which should be sharp from edge to edge.
But as of yet I am happy with the setup, everything seems to be ok.

Perfect focus accross the image does not always mean perfect alignment...

Bikerider said:

If you can get hold of a piece of kitchen worktop board, the central core is made up from wood chippings bonded together with resin with heat under pressure and is finished perfectly flat. It is also heavy! This will assist with the stability of the enlarger, because compare to the material I suggest, plywood is quite lightweight. I don't know where you live, if you have small stores that sell 'off cuts' that is where I got mine. A full sheet is very expensive but I only paid £3 (4$) for a piece 600mm x 600mm. It is easy to drill and fit fixing screws or bolts

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I agree!

I have a kitchen worktop fitted as a workbench in my hobby room.

I got my Kodak Precision enlarger without baseboard. I mounted it directly to the worktop with a mild steel backing plate underneath.