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John Layton
14-Dec-2017, 14:55
Having just completed construction of a horizontal enlarger - one of my remaining issues for "going large" (42X60) is that of reversing the curl of sheets cut from a 42" wide x 98' long roll of Ilford MG Classic paper...so that it will remain reasonably flat for upcoming printing/processing steps.

I know that others have had success in utilizing an existing curl to advantage for processing...but the system I'm designing needs to have the paper reasonably flat.

I've been using a home made jig to cut paper for 20X30's (from a 42"X98'roll) - which can easily be used to go larger. My question is: if I cut a 42X60 sheet, then "reverse roll" this onto a roughly 3" diameter tube - how long should I leave this sheet in this (reverse rolled) configuration to produce a sheet which will remain reasonably flat for the printing/processing duration?

xkaes
15-Dec-2017, 06:36
Congrats on your new enlarger.

This topic was recently discussed -- undoubtedly to death -- so if you do a search, it is likely to show up. I use rolls up to 54" in a horizontal easel. I have a home-made 8x5 foot easel hanging from hooks on the ceiling. The edges of the easel hold the paper in place, but only for very large pieces. But for ALL pieces, I tack it to the easel with lots of masking tape -- starting on the top edge. This is, of course, easier with B&W since I can use a safelight. With time, you can get it done with color, as well. Having an assistant is not a bad idea either.

I have never reverse rolled any paper before exposing it. The heavy weight of the paper, gravity, and masking tape do a good job of keeping the paper flat. PLUS, due to the distance between the negative and the paper (ex. 15 feet), depth of field is much greater, compared to small prints. Whether or not you decide to "reverse roll" etc., I'd start by using a "small" sheet and then start working up to larger pieces. You may discover that there is no problem that needs resolving.

John Layton
15-Dec-2017, 12:31
Thanks! While I'll probably be OK not reverse-rolling prior to printing....my concern relates to the fact that for processing I'll be building and using a single large tray - on a "tilt-able" base - with a tapered end with an attached (closeable) drain. I'll pour chemistry over the print and either rock it or simply leave it tilted with the drain open to pour into one of two open containers - the other being used to re-distribute solutions over the print. If the print is not reasonably flat going in (dry) - then I may have some difficulty getting solutions to sides/edges of print in a timely manner.

But I suppose I could mitigate these concerns by giving the print a good pre-soak to help ensure flatness for the remaining steps. I'll just have to set up and give it a try!

xkaes
15-Dec-2017, 13:51
You can go down the tray route, but you will be sorry. You could possibly find six foot trays at a hefty price -- or make them yourself -- but they are basically impossible to use. Unless you work in an auditorium, it's impossible. And getting the chemicals in and out is also a waste of time. And how do you regulate temperature?

The way to go is with troughs. Think of the snowboarders half-pipe -- with each end closed of. I use 12" diameter PVC pipe -- cut lengthwise and glued shut on each end. FOUR five foot troughs takes up less space than ONE 5x8 foot tray. PLUS troughs use a gallon or less of chemicals -- that's 1/10th what a tray would use!

With troughs, the curl of the paper is a plus. It makes them easy to slip in and slip out. Think of the snowboarders again -- they fall back INTO the pipe. With trays you will produce nothing but GIANT creases. If you think mural paper is heavy dry, try to handle it when it is soaked!!! THAT's when you want it rolled up, and that's what a trough does.

A company called MAXELL made some mural tube processors years ago, but you will never find them. The troughs are better anyway, because you can see how processing is progressing -- at least in B&W. Still, it's best to run a small sample through before you waste a BIG sheet of paper.

bob carnie
15-Dec-2017, 14:11
John

use a metal sheet for your easel paint it black, and find long magnete strips .. no need to reverse curl..

Also when doing large murals I would use under the bed plastic troughs, and scroll the paper as per above. three large units... and one big tray for washing.. You will use a lot of chem doing murals any way you go.

one single tray would be horrific unless you have a really well thought out system for putting chem in and getting out fast.. the flow marks would be impossible .

I have heard of people using tilted trays and spraying on the chems with a continuous reclamation ability but once again need to really work this system out.

I have been making murals for many years and the troughs are really good for Lamda rolls , I do 30 inch x 10 ft at a time with no issue.

also I do have enough room for trays so I can do it the easiest way which is tray to tray.. making some 20 inch x 48 ortho film today and did 6 units in a few years without a sweat.

bob carnie
15-Dec-2017, 14:20
172868

John this is a 48 inch sheet of film I am holding up.. my trays are exactly that. as you can see a simple set up , hard plastic trays with a large wash tray to my left...this image was taken 5 min ago.

xkaes
15-Dec-2017, 14:24
You will use a lot of chem doing murals any way you go.

With my 12"x5' troughs, I use one gallon of each chemical -- B&W or color. That's not that much more than a 20x24" tray. And with smaller troughs, say 8"x3', you could use a lot less.

I use a scooper to get the used chemicals out -- no big deal with only one gallon.

bob carnie
15-Dec-2017, 14:25
Thanks! While I'll probably be OK not reverse-rolling prior to printing....my concern relates to the fact that for processing I'll be building and using a single large tray - on a "tilt-able" base - with a tapered end with an attached (closeable) drain. I'll pour chemistry over the print and either rock it or simply leave it tilted with the drain open to pour into one of two open containers - the other being used to re-distribute solutions over the print. If the print is not reasonably flat going in (dry) - then I may have some difficulty getting solutions to sides/edges of print in a timely manner.

But I suppose I could mitigate these concerns by giving the print a good pre-soak to help ensure flatness for the remaining steps. I'll just have to set up and give it a try!

Pre soak would do the trick as the paper then would be flat and you could lay in place.. presoak in Safelight dude.

xkaes
15-Dec-2017, 14:27
172868

John this is a 48 inch sheet of film I am holding up..

Just curious, are you really nine feet tall?

You can save a lot of space, chemicals, etc. with troughs, but to each his own.

bob carnie
15-Dec-2017, 14:28
With my 12"x5' troughs, I use one gallon of each chemical -- B&W or color. That's not that much more than a 20x24" tray. And with smaller troughs, say 8"x3', you could use a lot less.

I use a scooper to get the used chemicals out -- no big deal with only one gallon.

How big are your prints.. I had a friend who used a jobo system for ciba prints with absolutely no issues... Many ways to skin the cat, I have settled on large troughs and large trays for my work.

bob carnie
15-Dec-2017, 14:30
Just curious, are you really nine feet tall?

You can save a lot of space, chemicals, etc. with troughs, but to each his own.

You may not notice but there is two images on that roll one High Key so dark and easily seen and a low key which is harder to see. I wish I was 9 feet for at least one day of my life.

xkaes
15-Dec-2017, 14:51
How big are your prints.. I had a friend who used a jobo system for ciba prints with absolutely no issues... Many ways to skin the cat, I have settled on large troughs and large trays for my work.

My Colourtronic tubes only go up to 3x4 feet. Above that, I switch to troughs. My biggest prints have been 5x8 feet (B&W) and my troughs are five feet long. My color paper is not five feet wide, but I can do eight foot color murals. After processing, I hang the prints on a clothes line with laundry pins and give both sides a good hosing down.

bob carnie
16-Dec-2017, 05:21
My Colourtronic tubes only go up to 3x4 feet. Above that, I switch to troughs. My biggest prints have been 5x8 feet (B&W) and my troughs are five feet long. My color paper is not five feet wide, but I can do eight foot color murals. After processing, I hang the prints on a clothes line with laundry pins and give both sides a good hosing down.

When you put in a large sheet of paper in the tubes, does not the paper roll up which then makes it difficult to get chemistry on all areas of the print equally..

When I scroll large murals I extend my development time and basically try to get each area exposed to the chemicals equally, bit of a balancing act but it works, I am trying to understand how this would work in a tube as the larger paper sizes would have to fold in to fit into the tube.

If I was to ever try to do a mural setup again I would take the Kodak K16 design with netting and biggie size it to handle large sheets of paper, I used this system in 1974 my first exposure to paper development and we made colour prints on Agfa paper using this machine.

Tin Can
16-Dec-2017, 06:14
Watch this. Seems to use tray and scroll. Bad music.

Shows easel usage also

https://m.youtube.com/watch?v=d-3IBi5tC08

John Layton
16-Dec-2017, 06:25
Way back when I was conducting photo workshops at Dartmouth...my students used large troughs laid out on the darkroom floor - and worked in pairs, one on each side of a given trough. Worked with long rolls of RC paper and this worked great. But very messy also!

Now...my darkroom sink measures 3 X 16 feet - and I currently use 2 x 3 foot trays (homemade) to do 20x30's. Works fine, and I know I can build 34 X 44 inch (appx.) trays to do 30x40's - can butt them together like Clyde Butcher does and gently draw prints from tray to tray. Then again, this would mean four trays total so only one fix (likely TF-4 with vent set on max) so I can fit a water bath - and likely set up a pumping system to handle liquids. Seem like a big pain to me, and potentially a big mess also.

So...thinking about troughs - I do not want them on the floor. In the sink - there is just one of me and a pair of hands alone would invite disaster (I think) so my thought here is to come up with pairs of long "clips" with handles - to hold paper evenly on edges as I dip through solutions. So...four troughs laid out as two pairs, then a single large holding/wash tray. Should work. I could then use the aforementioned clips to hang prints - with bottom clip acting as weight to help print dry flat.

My original idea consisted of a single large sheet of plexi...resting slightly off vertical with its bottom edge supported in a slightly canted trough - and I'd tape the print to this and use a pump with hose to douse prints with solutions. Would not need to move print at all...just change out solutions. Minimal print handling combined with space savings would be compelling. Plus...thinking about eventual 40x60's - logistics of this would be a plus I think. But then there is the aspect of streaking. Thoughts here is to combine a good amount of pre-soak with a more highly diluted developer. Other possible negative thought - hosing down prints would exacerbate oxidation? Want to think this through a bit more...comments?

So...(pardon my rambling - thinking out loud process) - seems like troughs might be the way to go - just hoping that when (and if) I get to 40X60's that my arms are long enough! Thinking I'll build troughs with plywood/epoxy - but maybe can find a source of reasonably cheap pre-made troughs...drywallers troughs too small but maybe something like long window boxes or something else from H.D. or Lowes?

Gotta make a choice soon...my first negative is loaded up and I'm ready to test - will do this by taping smaller paper sheets and batch processing in my regular trays - but will want full sheets soon after. At any rate...thanks folks!

bob carnie
16-Dec-2017, 06:35
John Posted

So...thinking about troughs - I do not want them on the floor. In the sink - there is just one of me and a pair of hands alone would invite disaster (I think) so my thought here is to come up with pairs of long "clips" with handles - to hold paper evenly on edges as I dip through solutions. So...four troughs laid out as two pairs, then a single large holding/wash tray. Should work. I could then use the aforementioned clips to hang prints - with bottom clip acting as weight to help print dry flat.


Bob reply-- this method is easy to scroll the paper , if you go to my youtube channel there is a video on scrolling large rolls through troughs.

forget the clips will only be an hassel

Tin Can
16-Dec-2017, 06:59
Bob, your domain is for sale. http://www.patersoncarnie.com/



John Posted

So...thinking about troughs - I do not want them on the floor. In the sink - there is just one of me and a pair of hands alone would invite disaster (I think) so my thought here is to come up with pairs of long "clips" with handles - to hold paper evenly on edges as I dip through solutions. So...four troughs laid out as two pairs, then a single large holding/wash tray. Should work. I could then use the aforementioned clips to hang prints - with bottom clip acting as weight to help print dry flat.


Bob reply-- this method is easy to scroll the paper , if you go to my youtube channel there is a video on scrolling large rolls through troughs.

forget the clips will only be an hassel

xkaes
16-Dec-2017, 07:00
When you put in a large sheet of paper in the tubes, does not the paper roll up which then makes it difficult to get chemistry on all areas of the print equally

Whenever I use tubes, the inside is always wet, and that always keeps the paper stuck to the tube. Even for the first use, I rinse it out, but I always rinse out after processing a sheet. The tubes don't use must chemical, but that and wet walls keep it stuck on the wall (I forget the term for that). That stickiness can sometimes make it difficult to get the paper into the tube, especially with large sheets.

I don't extend processing time -- in tubes or troughs -- but I always run a small test piece of the paper through to check.

bob carnie
16-Dec-2017, 07:04
Bob, your domain is for sale. http://www.patersoncarnie.com/

Not using it any more... Moderators here made me take down my labs address , as it was perceived as advertising.

xkaes
16-Dec-2017, 07:07
So...thinking about troughs - I do not want them on the floor. In the sink - there is just one of me and a pair of hands alone would invite disaster (I think) so my thought here is to come up with pairs of long "clips" with handles - to hold paper evenly on edges as I dip through solutions. So...four troughs laid out as two pairs, then a single large holding/wash tray. Should work. I could then use the aforementioned clips to hang prints - with bottom clip acting as weight to help print dry flat.

Perhaps because my troughs are so large and heavy, I have not found them to be messy at all. I can bump into them with my foot (and are WAY too large to fit in my 3x8'sink) and they don't move an inch. The liquid is only on the very bottom so there is no splashing.

A long time ago I thought about designing a "clip system" for each end of the paper, but discovered that simply rolling the paper from one end to the other in the trough works great and there is no spilling of liquid. Basically, the paper is always rolled up inside the through.

To empty, I simply use a scoop and a pail. Easy, simple, and clean.

bob carnie
16-Dec-2017, 07:10
Whenever I use tubes, the inside is always wet, and that always keeps the paper stuck to the tube. Even for the first use, I rinse it out, but I always rinse out after processing a sheet. The tubes don't use must chemical, but that and wet walls keep it stuck on the wall (I forget the term for that). That stickiness can sometimes make it difficult to get the paper into the tube, especially with large sheets.

I don't extend processing time -- in tubes or troughs -- but I always run a small test piece of the paper through to check.

Ok thanks.. so the large paper is rolled on itself then put in the tube for processing, I would think the inside of the paper would not get equal dispersion of chemicals.. I use a 16 x20 tube for large film on my jobo and at that size to have the film encircle the interior of the tube with out overlapping its a pretty big circumference. I would think the tube would have to be super size to do a 40 x60 inch print.

When I scroll I have the paper completely immersed in chemicals.. the trough itself holds about 40 liters to make this possible. I scroll towards myself, then rotate the roll and keep scrolling through the 4 min development. 90% of the time the paper is completely immersed in the chemicals.. After a day of this my wife can tell I am coming home a block away.

To the OP - if there is time I really would think the K16 design would fit your needs ..

xkaes
16-Dec-2017, 07:31
I only use 4 liters of chemical in each 12"x5' trough -- not very much really. The paper sinks to the bottom -- but does not stick very much -- and as I roll it from one end to the other, the chemicals are in the middle of the roll (the emulsion side). That keeps the paper down and through each roll, the paper gets covered by it. The same spot on the roll gets a new "splash" of chemical as it is rolled in reverse. I tend to use long development times anyway -- through dilution -- and have never had a problem with uneven development. I suppose with very short development times, ex. two minutes, that might be an issue. Just dilute and lengthen the development, etc. time. The paper does not need to be immersed in chemicals 100% of the time, it just needs to be "exposed" to it repeatedly -- which rolling (in a trough or a tube) -- accomplishes.

Tin Can
16-Dec-2017, 07:49
Not using it any more... Moderators here made me take down my labs address , as it was perceived as advertising.

Now I remember!

CRS

Pere Casals
16-Dec-2017, 08:29
Having just completed construction of a horizontal enlarger...

I've been testing a Hor. enlarger "prototype", solution I found to keep paper flat and in place is the adhesive way.

So my suggestion is place a flat surface on the wall (Thick Glass or Melamine White Panel, checking it is flat enough) and then spray on it 3M ReMount spray, paper will remain perpectly flat as if it was a vacuum powered easel, but more convenient !

Single problem is that you will need to spray some more ReMount glue after several days, after some weeks you may want to clean out all glue with "3M™ Adhesive Remover" for example and to spay new 3M ReMount.

If you use this way, remember protecting the sprayed glue by plastic sheet adhered on it when not using it (a RC paper used and discarted is perfect), in this way the glue will last more and no dust will adhere on it.

This glue looks like that in PostIt notes, it does not leave residues in the other object, so your photo paper won't take any glue. I feel like a 3M seller :) but you can use any other brand, of course.

Don't spray too much glue, just the amount that it keeps your paper flat and in place, this is much less than it looks.

I've played with that while trying to use a CAMBO 810 as an Hor. enlarger, placing in the back a Graflarger like DIY gadget. Also I use it to get paper flat under a MF enlarger. I'm happy with that way.

Regards.

bob carnie
16-Dec-2017, 09:07
I've been testing a Hor. enlarger "prototype", solution I found to keep paper flat and in place is the adhesive way.

So my suggestion is place a flat surface on the wall (Thick Glass or Melamine White Panel, checking it is flat enough) and then spray on it 3M ReMount spray, paper will remain perpectly flat as if it was a vacuum powered easel, but more convenient !

Single problem is that you will need to spray some more ReMount glue after several days, after some weeks you may want to clean out all glue with "3M™ Adhesive Remover" for example and to spay new 3M ReMount.

If you use this way, remember protecting the sprayed glue by plastic sheet adhered on it when not using it (a RC paper used and discarted is perfect), in this way the glue will last more and no dust will adhere on it.

This glue looks like that in PostIt notes, it does not leave residues in the other object, so your photo paper won't take any glue. I feel like a 3M seller :) but you can use any other brand, of course.

Don't spray too much glue, just the amount that it keeps your paper flat and in place, this is much less than it looks.

I've played with that while trying to use a CAMBO 810 as an Hor. enlarger, placing in the back a Graflarger like DIY gadget. Also I use it to get paper flat under a MF enlarger. I'm happy with that way.

Regards.

Sorry but this is probably the worst suggestion I have ever heard Pere .. Tried and true methods are metal walls magnets, hundreds of thousands of prints worldwide done this way if not millions when you consider Colour Mural Houses.

Pere Casals
16-Dec-2017, 10:12
Sorry but this is probably the worst suggestion I have ever heard Pere .. Tried and true methods are metal walls magnets, hundreds of thousands of prints worldwide done this way if not millions when you consider Colour Mural Houses.

Adhesive solution is also used for high performance film holders, I took the idea from that, sure a pro printer like you sure has better pro solutions, but I can ensure the ReMount solution works also perfecly, and it is a good solution for an amateur like me, as magnets do not ensure perfect flatness an provocates a paper waste.

bob carnie
16-Dec-2017, 11:57
Adhesive solution is also used for high performance film holders, I took the idea from that, sure a pro printer like you sure has better pro solutions, but I can ensure the ReMount solution works also perfecly, and it is a good solution for an amateur like me, as magnets do not ensure perfect flatness an provocates a paper waste.

Dude... fill your boots.. worst idea ever IMO... Have you ever made a mural Print??

John Layton
16-Dec-2017, 14:46
"Fill your boots." Ha! Never heard this one. Something from north of the border? About those magnets...do these work along a strongly curled paper edge? If so I think this sounds like a great solution. What worries me about using tape along such a strongly curled edge is the possibility that it may pull back a bit during exposure - which would be a veritable bummer...but then again I've never done either (tape or magnets) so I should just try one of these and see.

And xkaes...sounds like you simply place the rolled up paper into a trough...and start rolling this in a manner which will send solutions between layers. Is this correct? With the emulsion side inwards I see no problems with scratching...and because you are going with the paper's curl I could see that there would be only minimal danger of creasing (boy...do I ever hate it when I've not noticed a crease until a print is under glass!). I think I might worry about evenness though - but it sounds like you've gotten good results so its likely just a matter of practice. Still think I might start with the long clips...but maybe do a presoak first?

xkaes
16-Dec-2017, 15:06
All I've ever used is masking tape. It stays in place fine, but you need to use a lot and takes time -- magnets might be faster, but my easel is foamcore and wood. You can feel the edges of the paper and only cover a little with the tape. Once the top is in place, it's easy to get the other sides to line up.

The only problems with creases I've had is getting the paper into the easel -- that would be with same with masking tape or magnets -- and getting it out of the last trough and onto a clothes line.

Evenness of developing has never been a problem. Just keep your processing time as long as possible

Pere Casals
16-Dec-2017, 15:32
Dude... fill your boots.. worst idea ever IMO... Have you ever made a mural Print??

Bob, no, I've never made a mural print, but a mural print has lower flatness requirements than an smaller print, as paper to lens distance is greater then way wider "on paper DOF" can be guessed in the mural print case. If I enlarge a 8x10 to 16x20" and want perfect sharpness then paper good flatness is good, specially if paper comes from a roll, as I absolutely lack Pro gear the ReMount glue ensures same flatness than a vacuum table, just tell me a single reason why it is not going to work perfect. I repeat, sure a pro lab (like yours) has better solutions...

Bob, amateurs like me have to find the easy way, we lack pro gear and the expertise you have, so achieving a sound result normally it is a challenge, at least for me.

xkaes
16-Dec-2017, 16:13
I agree. At mural distances, film flatness get pretty irrelevant -- especially stopped down.

bob carnie
17-Dec-2017, 09:07
Bob, no, I've never made a mural print, but a mural print has lower flatness requirements than an smaller print, as paper to lens distance is greater then way wider "on paper DOF" can be guessed in the mural print case. If I enlarge a 8x10 to 16x20" and want perfect sharpness then paper good flatness is good, specially if paper comes from a roll, as I absolutely lack Pro gear the ReMount glue ensures same flatness than a vacuum table, just tell me a single reason why it is not going to work perfect. I repeat, sure a pro lab (like yours) has better solutions...

Bob, amateurs like me have to find the easy way, we lack pro gear and the expertise you have, so achieving a sound result normally it is a challenge, at least for me.

Pere- I am trying to save you a whole can of whoopass by trying crazy glue on a wall... sometimes its best to think about what someone who has done a career in printing murals... a metal wall or easel with Magnets is how all professional labs do it... buy them once and you are set for life.. These are long magnet bars .. I will post a picture later today when someone visits me with a Iphone...
Amateurs can purchase simple metal and magnets like the pro's.. After five cans of spray glue you would be ahead of the game $$$ by using metal.. The metal serves as a fantastic easel board and
any size configuration beyond 20 x24 easels can be set up in seconds.

John the magnets will definitely hold the paper, and you use the natural curl to your advantage ..once again I will post the setup I have later today...

Where to get metal... simple
Where to get long magnets??? not sure I have had mine for 30 years.

bob carnie
17-Dec-2017, 09:09
I agree. At mural distances, film flatness get pretty irrelevant -- especially stopped down.

You still need to focus on grain as with smaller prints, and stopping down has little or no effect . Sharp grain pattern is what on is looking for across the easel surface.

Pere Casals
17-Dec-2017, 09:35
you use the natural curl to your advantage ..once again I will post the setup I have later today...


You are right, I understand that the emulsion side is wound in towards the core, then natural curl is a help to mantain paper completely flat, just like 120 film in the holder, I guess.

I used the Re glue for paper sheets that I could not mantain flat because curved in the other sense, I used an auxiliary board for it.

bob carnie
17-Dec-2017, 09:41
The advantage of magnets and metal is that once done correctly one never has to touch the emulsion surface of the print and if using strong enough magnets at the corner set point you can move the paper across using the paper curl to your advantage and set top magnets as you go along ... once across all you do is set the bottom and side magnets..

There were days where I would process through 5 rolls of paper 50 inch Cprint... A econoroll for cutting the paper to exact size really helped , but I also am very comfortable cutting from the box , as I do these days. I would love to find the same econoroll I used where two rolls of paper can be put in the top and it feeds down to a cutter and a paper safe drawer below...

Tin Can
17-Dec-2017, 10:13
Try these magnetic thumbtacks. Listen to the larger one attach the paper.

https://youtu.be/qYbANzufnLM

xkaes
17-Dec-2017, 11:18
You still need to focus on grain as with smaller prints, and stopping down has little or no effect . Sharp grain pattern is what on is looking for across the easel surface.

These are two different point. First, focusing for a mural is not as easy as for a typical print for two reasons. Most importantly, you are far away from the focusing mechanism on the enlarger/lens. That means a lot of back and forth. In addition, with a typical focuser, you will be in the way of the image on the "easel". I use a tall Paterson type, so I can get out of the way.

Next, while stopping down, hopefully, will not change the grain, it will make a dramatic impact on the DOF at 10-15 feet, as opposed to 10-15 inches. With murals, typically, short exposures are preferred, but even opened wide, the DOF is much wider/deeper than any minor bulge/bubble in the paper.

bob carnie
17-Dec-2017, 11:58
I have always used a Peak focus device with a motorized focusing adaptor in my hand so seeing grain is dead nuts easy.. Also with a good method of aligning the negative base to the wall.
I have used wide open with grain sharp edge to edge, and closing down really does not improve anything .

I think the most important aspect of mural enlarging for focus is a properly aligned system , and for a horizontal enlarger system to magnet wall is not easy and cheap to do, I am not even sure
if there is many able to do this any more for people.

Best system I every heard of was a Vertical Unit where the Enlarger negative stage was on ground floor, and the lens stage and bellows were shooting through the floor to project on a horizontal metal easel. The photographer used a motorized focusing device and the easel was vacuum controlled using magnets as set points for the paper.

I am thinking my next darkroom will have tall ceilings and I will see if I can mimic this design.

xkaes
17-Dec-2017, 13:12
Best system I every heard of was a Vertical Unit where the Enlarger negative stage was on ground floor, and the lens stage and bellows were shooting through the floor to project on a horizontal metal easel. The photographer used a motorized focusing device and the easel was vacuum controlled using magnets as set points for the paper.

We all have our limitations in gear, wallet size, darkroom space, etc. I am not one of the "fortunate sons" to have access to motorized focusing, but somehow I manage. Magnets are not in my future, even though I could afford them. One of my Beseler flips horizontally, the other does not, but I use an inexpensive 90 degree front surface mirror (Squintar, Mirro-Tach,etc.) designed for on-camera use that accomplishes the same thing.

Murals are a challenge, for sure, but no matter what size a shutterbug can accomplish, they are fun and worthwhile.

I don't quite get how "closing down really does not improve anything". It always has and does for me -- in the field and in the darkroom. I suppose if you have all the best of the best gear for murals, DOF in the darkroom is not an issue, but it is for me, and others have brought up this point before.

bob carnie
17-Dec-2017, 14:02
I am not one of the fortunate sons either, I have accumulated my gear over a 40 year career printing for others, and with that experience worked with very good equipment and when I could purchase that said equipment for my personal lab.

Depth of field and Depth of Focus are two different animals.. and it can be argued ( to death ) both sides... I have always worked on having alignment issues covered and as well using the right lens for the negative size printing, as being the most important feature of darkroom work.

In my practical experience I have seen prints made wide open that exhibit sharp grain edge to edge, and I have seen the same for stopped down. I have never seen improvement in grain sharpness stopping down and I am aware that many say that it does... An Apo process lens for enlarging is a much different animal than an Apo capture lens for ones camera... I am very much aware of Depth of Field and how it works.. I am just not sure how much one gains stopping down at the paper surface... I guess if I made the grain unsharp then closed down and it got sharper , you would be absolutely correct... but I just have never seen that phenomenon.

Here is a test.. focus wide open and then put grain slightly out of focus.....minimal for example the width of the paper bubble you were describing.. then close down the lens.. does the grain become sharp.. I have done this test and it just dosen't snap into focus for me.

xkaes
17-Dec-2017, 14:24
My point was not about grain improving by stopping down the enlarging lens -- even though with MOST of the enlarging lenses I've used the grain is more clear when stopped down about two stops -- and then it gradually gets worse -- when viewed through a Micro-Omega grain analyzer.

My point was about DOF. If you focus an 5x7 INCH print and then raise the easel one inch -- it will be way out of focus. If you focus an 5x7 FOOT print and then raise the easel one inch -- it will still be in focus. And you can assure that by simply stopping down two stops.

Pere Casals
17-Dec-2017, 16:19
I have never seen improvement in grain sharpness stopping down and I am aware that many say that it does...


This is an interesting discussion.

Correct me if I'm wrong: If alignment is bad enough we are not to get a sharper grain by stopping the lens because as we stop enough to get the necessary DOF we also add diffraction enough to not see an improvement.

Sure you are able to get a perfect alignment, because premium gear and practice, perhaps others may get a good alignment but not a perfect one, having a miss that is not bad enough to no improve by stoping the lens a bit.

Anyway most enlarging lenses have to be stopped around two stops to be in the sweet spot...

Here shows that Componons are clearly better at f/11 than at f/5.6, specially off center. https://www.schneideroptics.com/pdfs/photo/datasheets/apo-componon/apo-componon_56_120_2.pdf (This is the 120 but LF intended glass works usually the same...).

But (with my limited experience) I agree that being accurate with alignment and using the good focal for the job it's what it makes the difference...