Dry mount pressed prints and wrinkles

[chris kleihege]

Hi gang,
Perhaps someone can solve one of those little mysteries I’ve never figured out myself. Why do I sometimes get wrinkles on the edges of my dry mount pressed prints, and why do I sometimes not? And for the first time it just popped in my head, if I have a print with wrinkles, can I re-wet the paper and press it again and eliminate the wrinkles?
Thanks,
Chris

[Bob Salomon]

Hi gang,
Perhaps someone can solve one of those little mysteries I’ve never figured out myself. Why do I sometimes get wrinkles on the edges of my dry mount pressed prints, and why do I sometimes not? And for the first time it just popped in my head, if I have a print with wrinkles, can I re-wet the paper and press it again and eliminate the wrinkles?
Thanks,
Chris

If you are using a Seal or similar dry mount press the proper procedure is to heat the board, tissue and print in the press, remove it and put a heavy weight on the sandwich till it cools.
If you are using a hardbed press like an Ademco then the sandwich is properly mounted when it comes out of the press.
If you are using a mounting tissue that allows you to reheat and remove the print, yes it can be easily removed. Otherwise it can’t be.

[Pieter]

I have had the same problem mostly when using the press to flatten prints. I have yet to see it on dry mounting. I did some experimenting and found the prints have less or no wrinkling of the edges when I put them in long side parallel to the handle, rather than perpendicular. My press has seen quite a bit of use before it came to me from a college photo darkroom, so it could be uneven heating or pressure that causes the problem.

[chris kleihege]

My mistake and to clarify, I am not dry mounting the prints. I simply put them in the Seal Dry Mount Press. Sorry, I will try to be more clear next time.

[Fred L]

When flattening prints in my Seal, I put the print between two sheets of acid free boards, then heat. Try to stick around 200°F for a minute or so. Haven't noticed any waviness along the edges.

[Richard Wasserman]

I had this problem and traced it to a lack of humidity when drying prints in the winter. Running a humidifier so the prints dried more slowly cured the wrinkled edges. About 1 minute at 200 Degrees in a press and then a few minutes to cool under a weight flattened them nicely.

[Ulophot]

My darkroom humidity lunges in the winter; in summer, I have to dehumidify. I get winter edge wrinkles, too, especially 8x10 and 11x14 (my largest), and yes, it is from their drying faster than the inner area or the print. I dampen a clean cloth with distilled water and use it to lightly dampen the back of the print's affected edge areas, often spreading inwards from the edge an inch or a bit more. Fifteen seconds or so in a warm press before flattening, or simply pressed under heavy flattener, does the trick.

[xkaes]

Chris,
You need to be specific about what you are using and what you are doing?
What exactly are you trying to attach to what with what?
At this point we are guessing -- and probably wrongly.

[Pieter]

Chris,
You need to be specific about what you are using and what you are doing?
What exactly are you trying to attach to what with what?
At this point we are guessing -- and probably wrongly.
I believe he is just flattening the prints, not attaching them to anything.

[chris kleihege]

Hi Xkaes and all,
I’m sorry as I didn’t add all info that may be relevant. I do not have a problem with 8x10 prints but with 16x20 and 20x24. I am using a Seal Dry Mount Press with 2 acid free boards, one on top of the print and the other on the bottom. The temperature on the press is set to 250 degrees because a teacher decades ago told me that was correct, no other reason. I am in Chicago and the relative humidity today is 40%, about normal for this time of year. I simply place the print in the press, wait a minute, and take it out. The problem is not with the edges being a bit wavy but with a few sharply defined wrinkles. And the wrinkles are not in each print, but are immediately apparent when removing “a problem print” from the press. That is all the info I can think of. And thank you to everyone weighing in. I greatly appreciate it.
Chris

[Duolab123]

It's as noted very dependent on humidity and how prints are dried. I have huge Seal steel weights that I use when mounted prints come out of the press.

I use a Pako drum dryer for drying FB prints, don't over dry, then put in a stack under a book etc.

Print flattening solution was used for decades, fell by the wayside when RC came along, and all the hysteria of archival washers etc etc.

[xkaes]

Chris,
So you are trying to dry prints by using a dry mount press? I assumed you were trying to attach a print to a matboard using sealing paper. Did you think that the "DRY" in dry mount press mean it's for drying prints? It's not.
I have never heard of drying a wet print using a dry mount press.
On the surface, I would image problems.
I'm assuming you are using NON-resin-coated paper -- that would cause its own problems.
Drying wet paper in a dry mount press will create problems because there is no where for the water to go! The heat from the press will expand the paper and the moisture can't escape.
Who told you to try this?
Are you trying to dry prints, flatten them, or both.
The HEAT in a dry mount press is used to attach the print to a mountboard using a sheet of dry mount adhesive paper. The heat melts the adhesive and they stick together.

[chris kleihege]

Please do not tell anyone that I was once an English teacher. I obviously cannot communicate clearly. The Seal press says “Dry Mount Press” on it, which leads to confusion. I am placing 16x20 prints that have dried on screens for 3 days into the press. I am not mounting the prints to anything, merely flattening them. Periodically I get this wrinkles on the edges. The wrinkles extend perpendicular from the edge for about an inch.
Thanks for sticking with me while I ineptly describe my problem.
Chris

[chris kleihege]

…and a further detail, the wrinkles are always on the short side of the paper. Thanks

[Drew Wiley]

Let me spell out, like others, the fuller procedure than your really asked for, because the greater context might help explain your immediate issue :

It is important not only to flatten your prints under a weight first for a few days, but to consistently pre-dry all your components at the time of mounting, except the drymount tissue itself. Unless you live in a dry climate where everything has been stored there long enough to acclimate to that, then, 1) pre-dry your two sheets of pressing board before each session; 2) BRIEFLY pre-dry your print between those boards maybe 20 sec; pre-dry your final mounting board between them, about 20 sec per side, all so far with the press merely closed, but not firmly clamped yet. Then firmly clamp it for the final mounting involving the tissue itself, which I will not outline here, except that with most tissues you do not want to actual press temperature to be above 210F !

Your described problem could well be because of the bad advice your teacher gave you. It might have been correct back when MT5 was the predominant mounting tissue, but current favorites like Seal Colormount or TriMount Drytac are engineering for lower temps. If temps consistently above 180F don't work, you need longer "dwell" time - that is, in the press. Substituting higher temps for longer time is a recipe for trouble. Since opening and closing the press repeatedly tends to lose some temp, I aim for slightly above 200 F on the dial itself. Of course, thermostats have to be checked if they are old; and Seal made a special kind of melting tape to test this. This pertains to drymount tissues per se. But too hot a temp might also over-dry the gelatin top layer and embrittle it, or most certainly, cause it to differentially curl in opposition to the paper layer behind, especially if you do have, as you suspect, some temp unevenness to your press platen.

So if you did go to full drymounting, you would still have a problem, yet one really quite easy to diagnose : 1) you are failing to pre-dry your components; 2) you are using too high a temperature, shocking that relatively humid material into differential modes of shrinkage, hence wrinkling.
But I should also mention a third variable : modern tissues fully bond under cooling; so after pressing, you IMMEDIATELY need to put the mounted print under a large flat weight for a reasonable period of cooling, maybe five minutes.

So no, I did not fail to read your original question, and how you are just trying to flatten prints in the press, and not necessarily fully drymount them. But full mounting is only way you're going to keep individual fiber-based prints flat for display purposes. Once they start re-absorbing humidity, there going to begin to wrinkle somewhat, regardless, unless they're left within a heavy stack inside a print box or cabinet drawer.

[Tin Can]

I store my Seal slightly open

I also use release paper and change it often

Since mine was almost new, used slightly by a woman, it is perfect

I keep it that way

no hammers needed

[xkaes]

Chris,
Thanks for the extra info.
Since your goal is simply to flatten the prints, you don't need heat. That might be causing the wrinkles.
Just leaving dried prints under a weight -- I use 1/4 glass -- will do the job. Some people use print flattening solutions.
But once it's flat, you need to do something to keep it flat.
You can simply put it in a frame under glass -- with or without a front mat -- but it's best to use dry or wet mounting on a flat "board".
That's where a dry mount press comes in. Other methods are basically glues that stick the print to a flat board.
So there are two steps. #1 -- process & dry your print and get it flat. #2 -- put it on/in something to keep it flat for display.

[Chauncey Walden]

Chris, when you dry your wet prints on a screen do you dry them face down or up?

[chris kleihege]

Hi Chauncey, I put them face up.

[Drew Wiley]

Face up, face down, makes little difference. Ya still gotta weight them down under heavy glass for awhile once dry. I always put em face up on fiberglass screens while drying, to prevent any hypothetical contamination of the emulsion surface, or any screen marks on true high gloss rather than fiber-based media. Some curling is inevitable until they are pressed under a weight.

[MartyNL]

I've experienced this problem. In my case, I believe it had to do with overly long washing of my 16x20" fb prints in a vertical washer.

[Drew Wiley]

Different kinds of FB paper can differ in their curl potential, even from the same manufacturer. Length of washing has little to do with it, unless its extreme. I wash all FB prints for an hour. Level of humidity during drying itself is a factor.

[Steve Goldstein]

Living here in the northeast, the indoor humidity can be really low in winter. As others have mentioned, lower humidity when drying leads to curlier edges that occasionally wrinkle when I flatten the dried print in my dry-mount press. Some papers are worse than others - Ilford MGWT seems to curl more than MG Classic, for example, but I haven't done exhaustive testing to demonstrate this.

The rate of drying also seems to have an effect - the faster the prints dry, the more curly the edges. And of course prints do dry faster in the low-humidity indoor heating season. I dry them face-down on Kostiner screens, which stack fairly closely. In winter I'll set the bottom screen on the floor (in our guest room, so there's no foot-traffic to stir up dust) and I always put an empty screen on top. Both measures slightly reduce the air circulation around the prints and hence the drying rate, and seem to give just a bit less edge curl. I'm not as particular in summer and the prints always dry with less curl then.

I trim the off the edges when I mount the prints so nobody besides me sees the occasional unsightly wrinkles.

[Tin Can]

I cut the tissue to exactly fit the print and tack it with iron onto much larger matt boards

Always amazed I get it it right so many times...

but not always

[Drew Wiley]

Well, I won't go into detail here on the specifics of my own tissue method, which is more precise and efficient than the traditional way, since actual drymounting was not the original question.

Steve - Indeed, MGWT curls a LOT more than either Classic or Cooltone. It has a heavier coating it seems, so more differential between emulsion and paper backing.

[bob carnie]

The cause of wrinkles IMO is the humidity is two low in the paper and it cringes as you put it into the press... think reticulation.

I keep my mounting room and prints to be mounted in a humidity controlled room and I use 4ply bottom rag and 2 ply rag top for the prints in our vacuuming press. Before the day starts we do one pressing of the boards before putting prints into the press.
It took me a few hundred spoiled prints to figure this out, this problem was mainly in the winter where in Canada the humidity is very low, now we humidify the room and paper before pressing.

[Duolab123]

The cause of wrinkles IMO is the humidity is two low in the paper and it cringes as you put it into the press... think reticulation.

I keep my mounting room and prints to be mounted in a humidity controlled room and I use 4ply bottom rag and 2 ply rag top for the prints in our vacuuming press. Before the day starts we do one pressing of the boards before putting prints into the press.
It took me a few hundred spoiled prints to figure this out, this problem was mainly in the winter where in Canada the humidity is very low, now we humidify the room and paper before pressing.

This was always EKCo's position on curling. I've had paper that sat too long in a papersafe curl up on me, dry, dry Iowa winter.

Kodak made a reverse bendy steamer to straighten prints. I've actually seen one, not in use.

Same theory behind print flattening solution, put a hygroscopic compound in the paper base to balance the moisture level.

I use a well maintained Pako dryer, as long as I don't cook the prints I get reasonably flat prints. Store in a flat file.

[MartyNL]

I've experienced curl. I've experienced waves. However, the very fine creases, wrinkles, only evidenced after hot or cold pressing, I have an Ademco 20x24", appears more like paper that has been stretched.
This has only happened to me with 16x20" fb paper when processed and more importantly washed in Nova vertical processors, using the official Nova clips.
Before the vertical washer, I'd never experienced this problem and I now make an effort not to leave the paper hanging and washing for no more than 40mins.

So I'm curious how the OP processes and especially washes his prints, whether it's done vertically or not and for what length of time?

[neil poulsen]

One caution about drying prints in a dry mount press; should one of the prints not be washed properly, the thick pad or other rag boards used as part of the dry mounting process can become contaminated by fixer or other chemicals. That can result in other prints becoming contaminated as well.

I have my own recollections from a teacher I had decades ago. At the beginning of the course, this particular teacher made it very clear, anyone caught drying prints in the dry mount press would receive an immediate "F" in the class. :)

[Tin Can]

Agree and my College Instructor, warned, nobody use the Hot Press without release paper or release boards

Which will protect the felt pads

I also worry about the silicone transfer, so I use fresh final paper to add another layer of safety

A big problem was shared drying screens, I would wash those and only use the top screens so Drips' would not contaminate my prints

We also had the steel cool down plate, I always used

I was friends with that great instructor for 22 years, but now he rages about MY beliefs

We no longer email

I gave him 4 OMEGA enlargers long ago as I prefer Beseler

[xkaes]

I can see how a neophyte might think a "dry mount press" is for "drying prints", and I also suppose that a lot of dry mount presses have been ruined in the process.

[Tin Can]

Parts are available

[xkaes]

A better approach would be to put the neophyte's head in the press!

[Tin Can]

Is that humour or tumor


A bette r approach would be to put the neophyte's head in the press!

[xkaes]

That's not the first thing I thought of putting in the press!

[Pieter]

I can see how a neophyte might think a "dry mount press" is for "drying prints", and I also suppose that a lot of dry mount presses have been ruined in the process.

First, I am not sure what could get ruined on a dry mount press by trying to dry a print in it. They are extremely simple, robust machines. Second, I would assume anyone with the knowledge to process fiber prints and access to a dry mount press would know better.

[xkaes]

I would assume anyone with the knowledge to process fiber prints and access to a dry mount press would know better.

That is exactly what I'm talking about.

Now imagine an idiot with his finger on the nuclear button.

Can't happen?????????????

[Pieter]

That is exactly what I'm talking about.

Now imagine an idiot with his finger on the nuclear button.

Can't happen?????????????
Quite a reach from a nuclear button to a dry mount press. Still. I don't think you can do any serious harm to a dry mount press trying to dry fiber prints.

[Tin Can]

I have seen more than a few with ripped thin cloth over pitted dry rubber

Perhaps someone forgot to it turn it off

I alway unplug mine after usage

[Pieter]

I have seen more than a few with ripped thin cloth over pitted dry rubber

Perhaps someone forgot to it turn it off

I alway unplug mine after usage
The rubber mat is replaceable. Not high tech.

[Drew Wiley]

Well, I don't ever trust silicone sheet or silicone release board DIRECTLY on the emulsion face - a bit of silicone can sometimes transfer over and leave a shiny spot, especially at excessive heat. Seen it. I always use a ragboard slip sheet in between. That fact creates a conflict with recommended manner for drymounting RC paper - another reason I never drymount RC, only FB papers. Glad I don't have to share my darkroom with anyone else. Too many things can go wrong.

[Tin Can]

Everytime I shared my last DR, the 'expert' needed a lot of help

I had to do everything, not because I am fussy, but the friend really knew nothing

When I first moved to my secure location, I tried real hard to donate time and gear to my Alma Mater

The reigning expert would not even meet me

I went to his swan song exhibit at the biggest local museum

His fawning acolytes blocked all

His work not novel, or interesting

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