hairline cracks in fiber-based prints dried on a drum dryer

[kwmullet]

Just got my "new" Prinz Jet drum dryer from eBay today. First run of prints looked pretty dismal -- very pitted. After a couple of hours of polishing the drum with Brasso, I ran another print through. it's much less pitted, but there's still some pitting. I think I'll have to figure out how to pull the apron so I can bleach and wash it to get the crud off.

There's a more disturbing issue, though. In at least two or three small areas of each print, I see what look like the lines around a mountain on a topological map. These are hairline cracks in the emulsion that I only see when looking at the surface of the print in glare. Instinctually, I'm thinking it might be because the dryer is either too slow or the heat is too high, neither of which have any more than a toggle switch control. No budget left to get a different print dryer. I've gotta make this one work.

The prints are on Ilford Multigrade fiber paper, but I've also seen it on one Azo print I ran through.

Anyone know if too-high heat or too-long on the drum is the culprit? Anyone ever crack one of these things open and know how to (a) pull and replace the apron, (b) adjust the speed of the dryer or (c) adjust the heat of the drum?

Thanks in advance,

-KwM-

 

[Aggie]

I had use of one a few years back. Are you place tihe print image side towards the drum? If so that is your problem. It goes face down on the canvas so the print will not be facing the metal drum. See if you can get a replacement canvas made. Even if you have to buy the canvas yourself and have someone make it. After you wash it, it may shrink. Then you are out the canvas and won't know the true size to have one made. This is FWIW

 

[kwmullet]

I had use of one a few years back. Are you place tihe print image side towards the drum? If so that is your problem. It goes face down on the canvas so the print will not be facing the metal drum. [...]

Hey... thanks for the speedy reply.

I am drying the prints with the emulsion toward the drum, intentionally. I want a high glossy finish. That's why I got the dryer.

Anyone out there got the the docs for this dryer? I know I can buy them online, but I'm both impatient and cheap. Does Prinz recommend against drying prints with emulsion against the drum? My dim recollection is that calling glossy paper "F" surface originates with the fact that the high gloss came from drying the prints with the emulsion against a "Ferrite" surface. Now, I don't know if the chrome drum of the Prinz Jet Dryer qualifies as a Ferrite surfice, but the high gloss from a fiber print dryer is what I'm after.

-KwM-

 

[Aggie]

problem with the emulsion side towards the drum is it melts. You are lucky it hasn't stuck to the drum yet. I've seen that happen. Then you get to take a razor blade and scrap your print off the drum. that is the source of your cracks and pitting. You just don't have it high enough to melt it further and have it stick. The machine was intended for the emulsion to be away from the drum just for this reason. You can't get a really high gloss shine by melting it, it just messes up the emulsion.

 

[glbeas]

One thing I used to do when I was ferrotyping prints was to wax the tin before I used it. A really good car wax worked for me but I wasn't worried about longevity of the prints. They came out with a really high gloss.
The pitting is usually from bits of trash between the print and the drum. Have you looked to see that the print has no particulates floating around with it in the wash?
Another thing is to be sure you have a solid bead of water between the print and drum as you load it. That will help make the gloss more even and also slow the drying a bit.
I've also seen print flattener solution that will help with the cracking. I think it was mainly glycerin and water.

 

[John_Brewer]

http://www.novadarkroom.com/mjb_pop/inst_fbdryer.htm may help.

J.

 

[kwmullet]

Well, from the research I've done so far, it appears that this new
dryer of mine is a gateway to the whole multilayered subject of
ferrotyping and glazing.

I'll sum up what I've found, mostly on the net, and boil down my
questions afterward. Corrections and illuminations will be greatly
appreciated.

I started out believing that when you had a fiber print dryer with a
heated chrome drum like this Prinz Jet I have, that the process of
drying the print with the emulsion against the drum was called
ferrotyping. It appears that's not quite the case.

[please insert "it appears to me that..." before all apparent statements
of perceived fact. I'm just omitting them to get on with it.]

THE ORIGIN AND VALUE OF GLOSS

Glossy paper prints were first desired by photojournalists because
press reproduction of the time demanded as smooth a surface as
possible in photographs. These days, those who desire high gloss
on their prints usually do so because it reduces the diffusion on
the surface of the print, giving more extreme dMax and dMin and
increasing the apparent dynamic range of the print. It also lends
a deep three-dimensional look to the print that might not be there
with the same image on a matte surface. The latter characteristics
are what I'm after.

FERROTYPING AND GLAZING

Two terms, ferrotyping and glazing, appear to be at the center of
the craft of producing a high gloss on silver gelatin prints. As a
side note, there appears to be a cultural English/American
distinction between the terms wherein glazing is used in England to
refer to both ferrotyping and glazing, but whereas the two
procedures are named separately in the US.

Ferrotypes are also a synonym for tintypes, the earliest
US-originated photographic process whereby a sensitized metal plate
was exposed, processed, and polished to a high sheen. It's this
polishing of a plate that, I supposed, has migrated the term
ferrotype to this process of adding gloss to paper silver gelatin
prints. In ferrotyping, an enamel or metal plate is polished with
a wax-based polished to a high sheen. Prints are squeegeed on to
the plate. Gradually, the prints dry from the edges in to the
center, and once they finally dry, they pop off the plate. I get
the impression that ferrotyping is usually done at room
temperature.

To avoid having to wax a plate, the successor to ferrotyping was
Glazing. In glazing, the polished wax is replaced by a hard-polished
chrome or similar surface and heat. To keep the emulsion from
cracking from uneven drying, prints are soaked in a solution of
gelatin and water to deter the speed with which water evaporates from
the emulsion as it acquires the gloss from the chrome plate or drum.
Extraordinary attention to detail is called for in keeping the chrome
clean and polished, a shortcoming of glazing being that you can't
just wax and polish your surface smooth. Another thing to watch
out for is that the cloth apron wicks up any impurity of
non-archivaly processed prints and could potentially contaminate
all prints done thereafter until you re-clean your apron.

As an aside, I've got a copy of The Photographer's Handbook, 3rd ed.,
by John Hedgecoe, and on page 60 it shows a nearly exact duplicate
of my dryer and calls it a rotary glazer, specifying that prints be
dried on it face up, against the heated drum.

Thanks to the reference from John Brewer, I've learned there's such
a thing as a glazing sheet, which could go between the print
emulsion and the drum. This might be a good alternative to forever
brasso-ing the chrome drum of my dryer.

That's what I've found out so far.


QUESTIONS

- I've read that heated drying (which I would presume includes
glazing) is contraindicated for toned prints, since it could have
unpredictable effects on the toner. Eventually, I'd like my
workflow to include solenenium toning followed by hot glazing.
Anyone have any comments on heated drying and/or glazing and
solenium-toned prints?

- Anyone using glazing sheets? What are they? Is there a cheap
alternative I can use that would be just as good, such as thick-ish
foil from a craft shop?

- I've heard that the gelatin and water solution is not archival and
promotes mold development in the dried print. Does this mean that
hot glazing is not suitable for archival intentions?

The adventure continues.

-KwM-

 

[John_Brewer]

My glazer/dryer whatever you want to call it has an optional sheet of chromium plated steel. Mine is very old! When I just want to dry FB prints put them face down and use a low heat. I did use the glazing sheet for some small prints, (some of the glazing sheet was rusty), but I didn't like the mirror like finish, it was too glossy.

J.

 

[happysnapper]

That surface of the dryer needs to be glass smooth if you don't want to have any pitting. I would not use Brasso on chrome, nor on anything that is going to have heat involved as it does contain some petroleum distillates that are not good to have around your photograph. There is a product used for cleaning metal surfaces that dates back a few years called Bon Ami. It comes in a bar form and is used with terry cloth and water. It requires some healthy elbow grease but is really remarkable in its ability to clean metal surfaces. It is slightly abrasive, so you need to clean things when you are done, don't leave residue. As for changing your dryer belt, forget about washing the old one, it needs to be replaced. take the old one with you to a fabric store, or a marine sales store that sells canvas, and by what you need and make your own, be advised the seam needs to be at an angle, or it will not pass through the rollers of your dryer...
You can also find ferrotyping plates at some garage sales here and there, made by Kodak too! I may have some floating around, I'll take a look. I always wondered what I would do with those once I started using RC for high gloss prints...

 

[gma]

In the previous millenium when I was an avid photo hobbyist there was a product for coating ferrotype plates. It was a liquid and I think it was referred to as a wax, but it was unlike any auto wax. A very thin coating was rubbed on the plate with a soft cloth then buffed when dry. I remember that it resulted in vastly improved glossy prints compared to a plate without the treatment. Keep in mind that any irregularities on the plate surface are transferred to the shiny print surface. A scratch on the plate will look like a crack on the print.

 

[Thilo Schmid]

I don't know the Prinz Jet Drum, but I use a Meteor Standard E, which should be the same in principle.
As was already said, you may place the paper face up or face down on the canvas. However, some drum dryers have an additional tension lever for high gloss (face to the drum). This adds tension to the rollers that press the canvas to the drum. The more gloss is desired, the more pressure is needed.
There are two principal parameters you must find out: temperature and speed. Optimal settings may vary with the paper you use. The optimum temperature is usually around 65°C (150°F). The speed is ok, if the paper peels off itself after one ¾ turn of the drum, usually with loud creaking. The louder it creaks the better, because louder creaks mean that large areas are coming loose at once.

If the emulsion cracks, your temperature might be too high (at least for the kind of paper you use) or you are using some force to peel the paper from the drum. I repeat: the paper must loosen itself. Some paper might need hardener and/or additional aids like Glanzol.

Replacing the canvas yourself is usually not easy but should not be impossible. Anyhow, you'll need some tools for doing that. Don't care too much for the condition of the canvas. Even if it does not look very appetizing, it takes a lot until it actually needs to be replaced. It is usually made of linen an can be washed in a usual washing machine.

Good luck

 

[kwmullet]

happysnapper:

Thanks for mentioning the Bon Ami. Being an ex-Navy photographer,
I just tend to throw Brasso at any shiny surface, but we do use Bon
Ami around the house. The form we use is from a powdered
dispenser, like Ajax or Comet. I haven't seen the cake variety.
I'm guessing the powdered form would work just as well.

That makes sense about there being petroleum distillates in brasso.
It took a lot of polishing to get most/all of the oil off the
surface of the drum, and maybe all of it didn't get off and some of
the pitting I have left might actually be from oil on the drum
pulling lint off the apron and pressing it into the emulsion.

gma:

Do you recollect if that ferrotyping polish was used in a heated
process or for room temperature ferrotyping? I'm thinking that
probably wouldn't be the ticket on the kind of hot drum + linen
apron glazer I've got.

Thilo:

Very helpful post. One more independant variable to add to the
mix -- roller tension. The other night, I got decided to pull the
apron off the dryer. It took the better part of an hour, but I got
it off, washed it once with soap and bleach, once with soap only,
then dried it on low for a long time, so now it should be
relatively cleaner and have less lint. I'll Bon Ami the drum
before I put the apron back on, to make sure I've got it as
polished as I can and have gotten the oils off from the Brasso.

Up until today, my darkroom has been out of commission and full of
saw- and sheetrock-dust since I've been adding electrical outlets to
the wall, ceiling and a small dry counter. To test the dryer, I've
taken previously printed prints of mine, soaked them in water for
fifteen minutes to an hour, then run them through. I haven't even
added photo-flo to the water, and I haven't run a test yet with the
gelatin mixture, so I'll do that with both of those once I get some
fresh prints, hopefully today.

Also -- as I was disassembling my dryer to get the apron off, I notice
that the wing nut on either side of the unit controlled tension on a
spring attached to what I'll call the primary squeegee roller. This
is the roller that, through the apron, first presses the print against
the drum. There's a corresponding roller (both rubber) on the
opposite side of the drum immediately before the print comes out from
under the apron, but it's fixed and not adjustable.

Sincee my dryer doesn't have adjustable heat or speed (I didn't see
any rheostats when I had it torn apart), perhaps this tension
adjustment might be the next best thing. If I reduce the tension on
the roller at the entrance to the drying path, it might press out less
water and let the print take a little longer to dry.

This is actually quite fun. I had no idea there was so many things to
consider when I dug into this issue. Hopefully, I'll have some
production quality prints to show for the effort.

Anyone have any ideas on the archival impact of the gelatin mixture?

-KwM-

 

[happysnapper]

I might be a little leery about using photo-flo on prints. There used to be a product made by Kodak called Ferrotyping Solution. I am not sure it is still around, but no doubt you can get the formulary from any of the multiple choices for such things.
As mentioned by others, heat control and speed will be the key to your success with this dryer. One of the screws you are looking at probably is the adjustment to keep the belt moving straight onto the drum. It would be the one that attaches to the roller closest to the front of the dryer, either directly or by another adjusting pin. How old is this dryer anyhow?
Good luck... looking forward to ongoing reports!

 

[kwmullet]

The front-most roller, which I haven't mentioned yet, is mounted on two sliding mechanisms whcih are mounted, in turn, on two screws that I can turn with black knobs on the front of the machine. That's my belt adjustment.

The wing nuts are on bolts that hold one side of tension spring on each side of a large black roller which is the roller which initially presses the apron against the drum as the prints travel into the dryer. The springs only control the amount of pressure exerted by the roller onto the drum itself. There's no space between the roller, apron or drum at this point, so it's not an apron tension adjustment.

Age? I really wish I knew. If the date is encoded in the serial number in some obvious fashion, maybe it's from 1962 or 1972 (more believeable).

Since details about the dryer are cropping up in this discussion, I grabbed some snapshots of it and put them at Dead Link Removed.

There's an overall shot, a shot of the nameplate (it's a Printz Automatic Print Dryer, model Jet, no. 2271.), a shot of the aforementioned knob/screw/roller for apron adjustment, and an attempt at a shot with the side plate removed to show the wing nut/screw assembly that controls the tension on the entry squeege roller assembly (*shrug*) or whatever it's called.

Bear in mind I've still got the apron removed. I've still got to go over the drum with bonami before I replace the apron.

-KwM-

 

[kwmullet]

Progress report.

I got Bon Ami powder, applied a small amount to a terry cloth lab towel and cleaned, rinsed with a wet towel, and polished with a dry towel the drum. With lots of cursing (no socket set handy) and exasperation, I managed to pull the apron back on, but it had shrunk in washing/drying, so one side if the top roller was pulled off track a little. At some point, I'll need to fabricate a new apron.

I lowered the tension on the bottom roller bar via the wing nuts as far as it would go.

For a flattening solution, I found a recipe at http://www.binbooks.com/books/photo/i/l/5DC46AF422&orig=1 , but it called for 2oz of gelatin and water to make one quart. The gelatin I had was powdered, so I didn't know how best to to translate that, so I used two of the four packets.

When my test print was done washing, I soaked it in the flattening solution for ten minutes, then ran it though the dryer/glazer.

The result was that the surface texture spotting was greatly reduced, as was the "topological cracking", but the print was still not good enough for customers.

For my next test run, I doubled the amount of gelatin in the water and cranked the tension on the bottom/entry roller way up. My thinking was that the cracking/rings was probably caused by uneven drying, so more gelatin would probably keep the water in the emulsion a bit longer. I thought perhaps spotty surface texture might have been due to bubbles trapped between the emulsion and the drum, so I increased the tension on the entry roller, and I also placed the next test prints on the apron at an angle, thinking that bubbles might be pressed out more easily by the roller that way.

Also, I hung the second test run prints by a corner until dry, then soaked in the flattening solution for 30 minutes before running through the dryer.

The result was prints almost (but not quite) free of "topological cracks" and texture spotting. I'll bet that if I stick to the same procedure, but double the amount of gelatin again, I might be good to go.

I read on photo.net that one person had a good results with Kroger gelatin (what I'm using) in sufficient quantities that he could see it floating in solution.

I've still got to research the impact of glazing on solenium toning. I've heard glazing is bad for toning, but haven't read yet WHICH kind of toning -- all? some?

cheers,

-KwM-

 

[kwmullet]

Just ran some more prints through the dryer but with two boxes (ea. box has four 1/4 oz packets) of gelatin dissolved in one quart of water for a flattening solution. The mottled surface effect is still there. About the only thing I can think of left to try is to add some photo-flo to the solution.

Should I be squeegeeing my prints before I put them on the dryer? I'm putting them on sopping wet. Maybe steam from all the moisture is causing this effect?

-KwM-

 

[Flotsam]

I've never had any luck in trying to ferrotype prints. Close, but one or two defects totaly ruin the print. Very frustrating.

Polishing the plate and then squeegeeing the wet print surface directly onto it is what I have heard but my solution was to decide that I really like a plain F surface. Works every time.

 

[kwmullet]

well... I'd all but given up trying to get glazing to work with this combination of paper (Ilford MG fiber-based) and dryer. I'd settled on just air-drying and cold-pressing my prints to get something remotely acceptable. I hate to settle.

in the course of a print job, I ran some contact sheets, which I do on single-weight Azo. Just to try something different, I mixed up a bucket of photo flo and dropped the prints in to use it as sort of a wet holding bin as I ran the prints through. The single-weight Azo prints came out nearly perfect. I'd say they would probably have been acceptable for customers, maybe not for exibition, though.

I tried the same thing with my next run of double-weight Ilford MG, and got the same problems again. I like the Ilford paper, I'd rather not switch papers, but there doesn't seem to be a combination of wetting/flattening agent and roller tension that will work suitably with this dryer and this paper. Within the next few weeks, hopefully, I'll find one of those double-sided glazing dryers with adjustable heat and the first thing I'll do is try a combination of lower heat and longer dry time to see if that works.

With the dryer I've got now, the prints nearly always pop off of their own accord within seconds of when they clear the last roller, so I think maybe the drying time is appropriate for this temperature, but I think the entire process is maybe a little to fast for this paper.

I ran across a post from someone, I think on photo.net, that intimated that contemporary papers are probably more challenging to glaze because the emulsions are thinner. I'll bet Azo has undergone comparitively fewer changes in the hundred-odd years it's been in production, and that might be a key to why it works so well.

I'm determined to eventually be able to get a high glaze with all my prints -- at least all the ones small enough to fit on a dyer. Maybe I'll eventually check out waxing.

if someone's got a recommendation for a VC paper with a thicker emulsion, wide tonal range and something that would still work with the Ilford MG filters, I'd be game to try it when my current box runs out.

-KwM-

 

[happysnapper]

Just a secondary or third thought...

Are you using hardener in your fix?

 

[kwmullet]

Nope. No hardener.

For me, that extra bottle in the rapid-fix kit is just packing. I don't use it with film or paper.

 

[Thilo Schmid]

I wonder how this machine could ever have worked. Each sort of paper needs a different speed on my drum dryer, depending on weight and other material properties of the paper base. I don't think that the emulsion is that critical and I got good results with MG FB as well. But I have to admit that the older ORWO and Brovira, which I still have, are more trouble-free in this regard.

When I saw the picture of your machine, my first thought was: what a tiny little thing! My drum dryer weights more than 100kg (>220 lbs) and has a huge oil-filled drum that is back-heated (i.e. the paper gets heat from both sides). A small drum has necessarily more surface curvature which causes more tension to the emulsion. I've never used such a tiny drum dryer, but it seems logical to me that the more the paper is bent, the more likely the emulsion will crack.

 

[kwmullet]

Hey... that's another good point!

I've about resigned myself not to sweat trying to get this to work. The current customer(s) will have to just get semi-gloss (which I really don't like). When the availability of funds and one of those temp-controllable double-sided dryers intersect, I'll resume my efforts with one of those.

That increased curvature thing might have more to do with it than anything else.

I worked one or two places that had the huge chrome-drum dryers, and someday, when I build my dream darkroom I'll try and find one, but I've never really used one. Alas, when they were available to me, I was too young, in too much of a hurry, and saw no reason to anything other than RC and usually machine-processed RC as well. Ick.

Oh -- and on a minor sub-thread, I've checked around and although other forms of toning are reported to react adversely to heated drying/glazing, selenium appears to weather it with no ill effects (according to various discussion group reports).

Thanks Thilo. I think that curvature idea may be the missing piece of the puzzle. I think that my dryer might have worked just fine with most of the contemporary papers back when it was made, but I've heard that most papers now have way thinner emulsions than those of 20 or more years ago.

-KwM-