Corner to corner focus issue

[logan2z]

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I recently made a print using my Beseler 23C II XL enlarger and observed that the bottom left corner was out of focus.  I thought that perhaps the enlarger was misaligned, but I carefully checked it's alignment and it's spot on.  After looking carefully at the negative, I believe it's not sitting flat in the carrier but is bowed slightly (I'm using the Beseler glassless carrier).  This issue may be exacerbated by the fact that the frame is the first one on the roll - the second frame does not have any focus issues across the image, nor have I observed this on any other roll of film I've made prints from. 

Although this hasn't really happened to me with any other images (at least nothing gross enough for me to notice), I'm wondering if it's worth buying the anti-newton glass carrier for the enlarger.  I realize that this means more surfaces to attract dust/fingerprints/etc. but I don't know of another way to keep a negative like this flat enough to print with good corner-to-corner sharpness.  It seems these carriers are still available from Beseler (BH Photo and Adorama sell them) but they are pretty expensive at $286.  Are they worth the investment?  

[M.Hilo]

Finding a AN glass carrier is always a good idea. True that you have more dust to deal with, but it also gives you more possibilities. Like printing smaller negatives, or more than one . . .

Try find one on the second hand market . . .

I don't know well the Beseler negative holder. Perhaps you can cut a mask from thin black pvc sheet, or from thin black carton, that you can place on top of this negative. So you help the neg holder to press flat better than it does. You just cut a bit wider than the negative's image . . . At least you have a chance to understand what is the cause of the problem.

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[Richardgb]

Before buying anti-newton glass etc., and if you don't have a general problem with unsharpness, you might try re-soaking and drying the problem neg.

However, film will rarely lie completely flat without glass; stopping-down the enlarger lens (Rodenstock recommended f/11 for the Rodagon as optimal, or f/8 for the Apo-Rodagons) works around the problem.

It was usually 120 film which had most problems with flatness, owing to the relatively thin base compared to the large unsupported area; 35mm and 4x5in generally suffered less as their bases were relatively thick. Storage at correct temperature and humidity, with no sudden changes, also helps.

[logan2z]

1 hour ago, Richardgb said:

However, film will rarely lie completely flat without glass; stopping-down the enlarger lens (Rodenstock recommended f/11 for the Rodagon as optimal, or f/8 for the Apo-Rodagons) works around the problem

Thanks for the reply.  I did have the lens (a Nikon Nikkor 50mm/2.8) stopped down to f8 when making the print.  

[adan]

When focusing enlargers, I always picked a point ~halfway between the center of the frame and the corner(s) as the aim-point for my focus-magnifier.

Just as with shooting "zone-focus" on the street - focus for a distance in between the two distances you want to keep sharp with DoF, since DoF works in both directions <----focus point---->.

Used the same technique when scanning film - set the 5000ED's AF point to be about halfway between the center of the image and the most-troublesome corner (if any).

[semi-ambivalent]

On 12/24/2018 at 8:56 PM, logan2z said:

I recently made a print using my Beseler 23C II XL enlarger and observed that the bottom left corner was out of focus.  I thought that perhaps the enlarger was misaligned, but I carefully checked it's alignment and it's spot on.  After looking carefully at the negative, I believe it's not sitting flat in the carrier but is bowed slightly (I'm using the Beseler glassless carrier).  This issue may be exacerbated by the fact that the frame is the first one on the roll - the second frame does not have any focus issues across the image, nor have I observed this on any other roll of film I've made prints from. 

Although this hasn't really happened to me with any other images (at least nothing gross enough for me to notice), I'm wondering if it's worth buying the anti-newton glass carrier for the enlarger.  I realize that this means more surfaces to attract dust/fingerprints/etc. but I don't know of another way to keep a negative like this flat enough to print with good corner-to-corner sharpness.  It seems these carriers are still available from Beseler (BH Photo and Adorama sell them) but they are pretty expensive at $286.  Are they worth the investment?  

http://fpointinc.com/glass.htm

http://www.conradhoffman.com/beseler01.htm

I can also vouch for the laser alignment tool by Versalab but don't know if they're still in business. Get an ANR negative holder; you won't regret it.

I made a lens holder by taking a piece of aluminum the same size as my 23CII-XL takes, had a large hole drilled in its center and then drilled three holes in both in a tripod arrangement for three small bolts to adjust the two plates against each other. spacing was maintained with a ring of black foam. A 30 second gimp rendered cross section is attached herewith. lower plate can be smaller. I missed my calling.

hth

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[logan2z]

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1 hour ago, semi-ambivalent said:

http://fpointinc.com/glass.htm

http://www.conradhoffman.com/beseler01.htm

I can also vouch for the laser alignment tool by Versalab but don't know if they're still in business. Get an ANR negative holder; you won't regret it.

I made a lens holder by taking a piece of aluminum the same size as my 23CII-XL takes, had a large hole drilled in its center and then drilled three holes in both in a tripod arrangement for three small bolts to adjust the two plates against each other. spacing was maintained with a ring of black foam. A 30 second gimp rendered cross section is attached herewith. lower plate can be smaller. I missed my calling.

hth

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Simply register for free here – We are always happy to welcome new members!

Thanks so much for the links.  I believe I've got the enlarger aligned pretty well but I'll use the info you provided to verify it.  

FYI, Versalab is alive and well - I recently purchased their print washer.  They still manufacturer their laser alignment tool as well.  It's a bit pricey but may be worth the investment.  

[Richardgb]

On 12/30/2018 at 3:57 AM, semi-ambivalent said:

http://fpointinc.com/glass.htm

http://www.conradhoffman.com/beseler01.htm

I can also vouch for the laser alignment tool by Versalab but don't know if they're still in business. Get an ANR negative holder; you won't regret it.

I made a lens holder by taking a piece of aluminum the same size as my 23CII-XL takes, had a large hole drilled in its center and then drilled three holes in both in a tripod arrangement for three small bolts to adjust the two plates against each other. spacing was maintained with a ring of black foam. A 30 second gimp rendered cross section is attached herewith. lower plate can be smaller. I missed my calling.

hth

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Sorry if this sounds obvious, but a laser alignment tool will ensure the film, lens-board, and paper planes are parallel - but it won't help film flatness (for which glass is needed).

The name for such devices, by the way, is a collimator, and they don't need to be laser-powered. Many years ago I used such an instrument manufactured by Rodenstock to critically align a customer's enlarger - he was using a point source in his condenser head to illuminate the film, a system which shows up the slightest discrepancy. Fortunately, the enlarger (a De Vere) was constructed to allow adjustment, not relying on manufacturing precision for alignment. (In the factory, final alignment was done using a jig, which was good enough for more usual semi- or fully-diffuse light sources.)

If things are way out, then a high-quality spirit level could be used as 'first aid' - mine (a normal DIY brand) claims to be accurate to 1mm over 1 metre - provided the bubble was viewed consistently.

[semi-ambivalent]

3 hours ago, Richardgb said:

Sorry if this sounds obvious, but a laser alignment tool will ensure the film, lens-board, and paper planes are parallel - but it won't help film flatness (for which glass is needed).

I use a negative holder with ANR glass on top for just that reason. In the old glassless days I'd listen for the negative to pop before making the exposure. That's why I included a link to a provider of ANR glass who will cut to order. OP can craft a solution without giving Beseler a couple hundred dollars. The Beseler 23C series is like a checker cab; tough as ever but it's not a watch and so it wasn't built like one.

thx

[logan2z]

On 12/29/2018 at 7:57 PM, semi-ambivalent said:

http://fpointinc.com/glass.htm

FWIW, I've tried to contact the company a couple of times but have yet to receive a reply.  Do you know of any other good sources of AN glass?  Still can't get my head around paying Beseler nearly $300 for a simple 35mm negative holder.

Edited January 24, 2019 by logan2z

[semi-ambivalent]

17 hours ago, logan2z said:

FWIW, I've tried to contact the company a couple of times but have yet to receive a reply.  Do you know of any other good sources of AN glass?  Still can't get my head around paying Beseler nearly $300 for a simple 35mm negative holder.

Twenty seconds on Google gave me www.betterscanning.com

[logan2z]

8 minutes ago, semi-ambivalent said:

Twenty seconds on Google gave me www.betterscanning.com

Funny enough I do actually know how to use Google  But what I was really wondering was if you had any personal experience with a company that sells AN glass.  Like someone who might actually respond to a customer inquiry.

[semi-ambivalent]

2 hours ago, logan2z said:

Funny enough I do actually know how to use Google  But what I was really wondering was if you had any personal experience with a company that sells AN glass.  Like someone who might actually respond to a customer inquiry.

I used Focal Point and bought doubles in case I broke a pair. I can only suggest you keep trying to contact them, at least to get a definitive answer. A lot of companies are on the internet but don't do internet business in a manner that customers have come to expect from internet business. At least give FP a chance to reply. (I also bought a Beseler glass neg carrier. Sometimes you just have to spend the money, or make something yourself, like McGuyver. Think of it as 2 Italian leather camera straps; it goes down a bit easier then.)

[logan2z]

2 minutes ago, semi-ambivalent said:

I used Focal Point and bought doubles in case I broke a pair. I can only suggest you keep trying to contact them, at least to get a definitive answer. A lot of companies are on the internet but don't do internet business in a manner that customers have come to expect from internet business. At least give FP a chance to reply. (I also bought a Beseler glass neg carrier. Sometimes you just have to spend the money, or make something yourself, like McGuyver. Think of it as 2 Italian leather camera straps; it goes down a bit easier then.)

Unfortunately you're right about a lot of small companies - they put up a little web site with an email address and a contact form but never bother to look at any of the electronic correspondence.  Surprising that this still happens in 2019 but it does.

I'm usually not such a cheapskate when it comes to photo gear.  I guess the reason I'm hesitant to buy the Beseler AN glass carrier is that it's not clear that the glassless carrier is the source of my focus issues.  Besides the curved negative that I mentioned in my original post, I've also been getting 'focus drift' with the enlarger where the image is in focus initially but slowly (or sometimes not so slowly) drifts out of focus.  I've tried snugging up the screws behind both the condenser and negative stages but that doesn't seem to have cured it.  I spoke to someone at Beseler technical support and they figured it was the upper section containing the condenser that was slipping but, as I mentioned, tightening the screws doesn't seem to have resolved the issue.  I mentioned buying an AN carrier and they said not to bother(!).  Maybe I'll just suck it up and buy the carrier and see what happens.  I guess it can't hurt to have it regardless..