Saunders/LPL 4500 II - Troubleshooting Light Projection Issue

[xvelids]

Hi fellow LF Community!

I've been trying to troubleshoot my Saunders/LPL 4500-II set up - it may be a simple solution, but I've been unfortunately stumped for the last couple of days! Had no issue printing 35mm or 6x7 on my set-up, but once I decided to print my 4x5 negatives I ran into a problem on the enlarger where the light projection is uneven and smaller than the print size. I am unsure if this is a blockage issue related to the negative stage plate or something else. I've included some pictures and measurements below of my set up for context.

To further technically clarify my set-up - this is a Saunders LPL 4500-II. Lens = APO 150mm Rodagon N. I am using a LPL 4x5 anti-newton glass carrier, the negative stage plate is the masking attachment version (for reference - http://store.khbphotografix.com/Masking-Attachment-for-LPL-and-Saunders-LPL-4x5-Enlargers.html), not the standard negative stage plate (for reference - http://store.khbphotografix.com/Negative-Stage-Plate-for-LPL-and-Saunders-LPL-4x5-Enlargers.html).

The images I included show the negative, my enlarger set-up, the lens w/lens board, contact sheet/print, print with the light loss where the chin and the top of the head is obscured, the easel (set for a 8x10 print) and another easel shot, but with the negative carrier rotated on the negative stage plate. With the shape of the blockage, I think the problem is with the negative stage plate as you can see in the photograph. From the negative stage plate-to-the-lens board measures ~ 8 5/16 in; Lens Board-to-Lens measures ~ 1 7/8 in and the Lens-to-Paper measures ~20 inches.

This post has the first initial images and my subsequent one will have the rest! Thank you for reading and hope to hear from the community. I hope it's an easy fix and perhaps one that I simply overlooked! Let me know, thanks!

[xvelids]

The rest of the images illustrating the print and the easel. 218362218363218364

[Oren Grad]

I use a 4500II with masking stage and glass carrier and have no problem printing 4x5 negatives with a 135mm EL-Nikkor.

With apologies if these questions seem stupid or obvious:

* Are the blades in the masking stage all the way open?
* Does your head have the standard 4x5 diffusion box, or is there any chance that you have one of the smaller-format diffusion boxes installed?

[agregov]

Pop the top off and check your mixing chamber. They come in three different models: 4x5, medium format and 35mm. You might have the medium format mixing chamber. If so, you’ll need to purchase a 4x5 mixing chamber. You can buy them new or often used.

[Oren Grad]

To avoid any confusion for the OP: "diffusion box" = "mixing chamber". We're saying the same thing.

[xvelids]

Hi! Thanks for the replies. I really appreciate it.

1. I doubled checked the negative stage plate - the masking attachment is wide open.
2. I pulled out the diffusion box and it looks like to my eye that this may be the medium format diffusion box.

Attaching an image of my diffusion box/mixing chamber for your review. I also found a picture of the three diffusion boxes together for reference. Do you guys think this is the medium format diffusion box? Also, my diffusion box is quite yellow (I guess from age)...would that affect print quality in the foreseeable future?

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[Michael R]

The more yellow it is, the less contrast you will get on variable contrast papers.


Hi! Thanks for the replies. I really appreciate it.

1. I doubled checked the negative stage plate - the masking attachment is wide open.
2. I pulled out the diffusion box and it looks like to my eye that this may be the medium format diffusion box.

Attaching an image of my diffusion box/mixing chamber for your review. I also found a picture of the three diffusion boxes together for reference. Do you guys think this is the medium format diffusion box? Also, my diffusion box is quite yellow (I guess from age)...would that affect print quality in the foreseeable future?

218384 218385

[PRJ]

Looks like the medium format box to me. I'd take the diffusion plate off and see what is going on inside. That looks bad. You just need to remove the two screws on the side to take the plate off IIRC. You are going to need a 4x5 box though if you want to print 4x5. On the upside, once you buy the 4x5 box you can use it for medium format as well. Most people do that (I do) since it is hard to find the medium format box.

[ic-racer]

If you need to make a new diffusion plate, a PhotoTrio member is experimenting with diffusion material for a project right now. Maybe some useful information there about available diffusion material.

https://www.photrio.com/forum/threads/printalyzer-densitometer-a-compact-budget-friendly-densitometer-project.185429/#post-2449581

[Sal Santamaura]

If you need to make a new diffusion plate, a PhotoTrio member is experimenting with diffusion material for a project right now. Maybe some useful information there about available diffusion material.

https://www.photrio.com/forum/threads/printalyzer-densitometer-a-compact-budget-friendly-densitometer-project.185429/#post-2449581Note that the plastic plate on a 4500 II 4x5 diffusion box is denser in its center than at its edges. In other words, it's a "center filter" designed to even illumination on the negative. Using a uniform material to replace it will result in a center "hot spot."

[Drew Wiley]

My favorite diffusion material is 1/16 inch "Sign White" Acrylite (similar to Plexiglas). This transmits more light than standard translucent white acrylic of the same thickness. If falloff correction is needed, this material can be ground thinner towards the corners, but that's a tricky acquired skill. So just burn in the corners and edges when using a 150, or use a longer enlarging lens like a 180 if you don't want to burn-in. No big deal.

[Sal Santamaura]

My favorite diffusion material is 1/16 inch "Sign White" Acrylite (similar to Plexiglas). This transmits more light than standard translucent white acrylic of the same thickness. If falloff correction is needed, this material can be ground thinner towards the corners, but that's a tricky acquired skill. So just burn in the corners and edges when using a 150, or use a longer enlarging lens like a 180 if you don't want to burn-in. No big deal.A 180mm enlarging lens will not eliminate the edge falloff resulting from a uniform diffusion plate on that mixing box. The falloff would result from the enlarger's design, not cosine fourth loss of a 150mm lens.

[Michael R]

Yes very good point.

Better to just buy a new 4x5 box I think.


Note that the plastic plate on a 4500 II 4x5 diffusion box is denser in its center than at its edges. In other words, it's a "center filter" designed to even illumination on the negative. Using a uniform material to replace it will result in a center "hot spot."

[Oren Grad]

I've only ever had the 4x5 diffusion box. At least for my printing habits - I've never enlarged a full- or half-frame 35mm negative beyond what will fit on an 8x10 sheet - even the 4x5 box provides ample illumination and short printing times even for the smallest formats. So standardizing on the 4x5 box has been effective and convenient for me.

[ic-racer]

Note that the plastic plate on a 4500 II 4x5 diffusion box is denser in its center than at its edges. In other words, it's a "center filter" designed to even illumination on the negative. Using a uniform material to replace it will result in a center "hot spot."

Good point.

[Drew Wiley]

Lens falloff and uncorrected diffusion chamber falloff are additive. Technically, a different diffuser would have to be ground for each significantly different lens. Longer lenses are in fact a partial solution. So is having a well designed oversized diffusion chamber or mirror box, at the expense of more concentrated light of course. I've also used carefully crafted stainless mesh scrims inside of mirror boxes in lieu of ground diffusers. Industrial sieve mesh comes in quite a variety of very fine wire sizes. Another trick is lenticular linear arrays, a very special kind of fresnel lens. Of course, all these options can hypothetically be combined. Relatively few enlarger heads are ideal in this respect right out of the box.

[Sal Santamaura]

Lens falloff and uncorrected diffusion chamber falloff are additive...So? The LPL 4x5 mixing box variable-density diffuser is designed to present negatives with even light. It's got nothing to do with lens falloff.


...Technically, a different diffuser would have to be ground for each significantly different lens...Technically, given that the LPL 4x5 diffuser is a molded part that fits over / wraps around and is screwed to the metal mixing box (as seen in the second image of post #6 above), it's far fetched to think that anyone would be "grinding" any kind of replacement.


...Longer lenses are in fact a partial solution...An enlarging lens 30mm longer than 150mm would in fact be absolutely valueless in solving the OP's problem.


...So is having a well designed oversized diffusion chamber or mirror box...This thread is in the Darkroom Equipment category, not LF DIY. The OP's not building an enlarger. No oversized mixing box will fit inside an LPL 4500 II housing. Real world constraints must be dealt with.


...I've also used carefully crafted stainless mesh scrims inside of mirror boxes in lieu of ground diffusers. Industrial sieve mesh comes in quite a variety of very fine wire sizes. Another trick is lenticular linear arrays, a very special kind of fresnel lens. Of course, all these options can hypothetically be combined...None of those "tricks," singly or in combination, would be of any use. The OP's mixing box is one designed for medium format negatives. There's no way to make it cover 4x5. Period.


...Relatively few enlarger heads are ideal in this respect right out of the box.The LPL 4500 II's only "shortcomings" are that it illuminates just enough area for 4x5 negatives, frustrating those who embrace the affectation of printing rebate areas, and its 4x5 negative carriers slightly further restrict things by having a openings of only 93.5mm glass / 93.7mm glassless in their short dimension. When equipped with the correct factory mixing box, this enlarger's damn near ideal in terms of 4x5 illumination evenness.

The OP would be well advised to obtain a correct mixing box. While currently out of stock, here's one good source that should be able to provide more information on when it might once again become available:


http://store.khbphotografix.com/4x5-Mixing-Box-for-LPL-and-Saunders-LPL-4x5-Enlargers-LPL55545.html

[PRJ]

I've only ever had the 4x5 diffusion box. At least for my printing habits - I've never enlarged a full- or half-frame 35mm negative beyond what will fit on an 8x10 sheet - even the 4x5 box provides ample illumination and short printing times even for the smallest formats. So standardizing on the 4x5 box has been effective and convenient for me.

Oren if you ever get a chance to buy the 35mm mixing box I'd recommend it. The print quality with the combined diffusion/condenser is great. Probably the best 35mm enlarger I've ever used. Better than my Focomat 1c even.

[Drew Wiley]

I have no intention of responding in detail to any chronic gadfly whose only purpose in commenting seems to be an attempt to maliciously discredit me and undermine anything I post, regardless of what it is. I've actually built high-performance custom colorheads, precision mirror boxes, everything I mentioned. I know what works, and am not guessing about any of this. But for most people, a bit of simple corner and edge burning-in to even out print densities is going to be an acceptable solution. Of course, all this is predicated by a properly sized mixing box to begin with.

[Sal Santamaura]

I have no intention of responding in detail...Of course not. What can you post other than further arm-waving irrelevancies?


...chronic gadfly whose only purpose in commenting seems to be an attempt to maliciously discredit me and undermine anything I post, regardless of what it is...I scan and pass by most of the things you post, Drew. My responses to a select few of them are submitted for the sole purpose of correcting erroneous information that new readers might be mislead into believing as a result of your know-everything-about-everything attitude and 15,000+ loquaciousness.


...I've actually built high-performance custom colorheads, precision mirror boxes, everything I mentioned. I know what works, and am not guessing about any of this...A perfect example of irrelevant arm-waving.


...But for most people, a bit of simple corner and edge burning-in to even out print densities is going to be an acceptable solution...The OP has a medium format mixing box. No amount of corner and edge burning-in will accomplish anything with a 4x5 negative.


...Of course, all this is predicated by a properly sized mixing box to begin with.Of course, that's the whole point. Why do you persist waving your arms about building things, longer lenses and edge burning when the OP has a commercially produced enlarger with one incorrect part that simply needs replacing with the correct one?

Gadfly? Pot, meet kettle.

[Drew Wiley]

Someone is on permanent Ignore. Wish the name didn't even appear.

[Sal Santamaura]

Someone is on permanent Ignore. Wish the name didn't even appear.Excellent. Makes refutation much easier when multiple posts aren't necessary to convincingly achieve it. :D

[ic-racer]

Any luck in finding a 4x5 mixing chamber?

[Jay Wolfe]

Of course not. What can you post other than further arm-waving irrelevancies?

I scan and pass by most of the things you post, Drew. My responses to a select few of them are submitted for the sole purpose of correcting erroneous information that new readers might be mislead into believing as a result of your know-everything-about-everything attitude and 15,000+ loquaciousness.

A perfect example of irrelevant arm-waving.

The OP has a medium format mixing box. No amount of corner and edge burning-in will accomplish anything with a 4x5 negative.

Of course, that's the whole point. Why do you persist waving your arms about building things, longer lenses and edge burning when the OP has a commercially produced enlarger with one incorrect part that simply needs replacing with the correct one?

Gadfly? Pot, meet kettle.


Usually Drew is waving something else which is equally unimpressive!

Maybe someday he will post some his impressive images and pix of his impressive physique. Until then it’s just long winded hot air.

[xvelids]

Unfortunately not so far...been looking on Craigslist, LF Forum, Phototrio, Ebay and KHB. I contacted KHB, but unfortunately they are out of stock. In terms of ebay, they're selling the entire unit as opposed to the mixing box and neither sellers who I contacted have mentioned the condition of the mixing box. I did however inquire about it today. Hopefully, something will turn up!

[Drew Wiley]

One more to Ignore. Thanks for making it easy.

[agregov]

Unfortunately not so far...been looking on Craigslist, LF Forum, Phototrio, Ebay and KHB. I contacted KHB, but unfortunately they are out of stock.

Looks like you can special order one on B&H new. But I'm sure a 45 box will show up for auction. They're pretty common. Hang in there!

[xvelids]

Thanks! I actually visited B&H on Tuesday and unfortunately, it's on back order. I hope to see one soon!

[PRJ]

It looks like KHB has both the internal styrofoam mixing box and a replacement 4x5 diffuser in stock. You might be able to strip your medium format box and install those. Might be worth asking them if it is possible solution for you.

Hope that helps.

[ic-racer]

Yes if you can get or make the 4x5 version you can use that for everything smaller too.

[xvelids]

Before I consider stripping my medium format box...what do you guys think of the condition of the box? I'm attaching an image of the inside. It seems that the yellow-ing is actually just the masking tape inside and the Styrofoam seems in ok condition actually!

218589

[PRJ]

Looking at that I am wondering if someone didn't take a 4x5 box and just add more styrofoam inside it. That looks like a bodge job. You might have been sitting on a 4x5 box all along. I'd take out that styrofoam. You'll probably be in business. Looks like you might be lucky.

[Sal Santamaura]

Before I consider stripping my medium format box...what do you guys think of the condition of the box? I'm attaching an image of the inside. It seems that the yellow-ing is actually just the masking tape inside and the Styrofoam seems in ok condition actually!

218589

As long as the box is structurally OK, everything should be fine if you buy the 4x5 EPS foam liner and diffuser. Mine's not accessible right now to open and examine, but I suspect there wouldn't be any masking tape involved with the 4x5 box. If memory serves, its foam fits snugly inside the metal and is held by the diffuser. Even if there is a need to secure the foam in place, a well-placed drop of super glue ought do the trick.

[xvelids]

Looking at that I am wondering if someone didn't take a 4x5 box and just add more styrofoam inside it. That looks like a bodge job. You might have been sitting on a 4x5 box all along. I'd take out that styrofoam. You'll probably be in business. Looks like you might be lucky.

- That's really disconcerting! I'm curious to know how to differentiate the 4x5 mixing box from the 6x7 mixing box then? When I was looking at the box, it did strike me as unprofessional because the masking tape was really poorly applied.

If I take out the Styrofoam...all I have to do is insert this liner? I'm attaching the link - http://store.khbphotografix.com/Liner-for-LPL-and-Saunders-LPL-4x5-Mixing-Chambers.html And yes, the mixing box is structural sound, but the styrofoam is quite flimsy.

I wouldn't need the diffusion panel...would I? I might just purchase extra to have because sourcing these parts is proving to me fairly stressful!

Also, now that it's come to my attention that enlarger mixing box had issues...how should I check in on the condition of the dichroic module? My understanding was that the contrast filters were fade free, but should I have a look at that too?

[Sal Santamaura]

...If I take out the Styrofoam...all I have to do is insert this liner?...Yes.


...I wouldn't need the diffusion panel...would I?...Scroll up and look at the image of all three mixing boxes. The medium format box's panel exhibits a circular pattern around its area of coverage. The 4x5 panel doesn't. I'd say the answer to your question is "yes."


...how should I check in on the condition of the dichroic module? My understanding was that the contrast filters were fade free, but should I have a look at that too?Not really necessary unless you detect mechanical problems operating their controls or their effect on printing changes.