Tri-X 400: How to flatten?

[Ronald M]

Put it a 36 exp sleave, roll emulsion out, place in glass 24/48 hours.

Or weight down with books.

 

[Ranchu]

edit: oh you said no books, that's what I use. Nevermind.

 

[Photo_Smith]

The refractive index of glass and film is not that close,

Close enough, Photographic gelatin is 1.44 film can be as high as 1.56 both are as close (crown glass is 1.52) as need to be for it to work.

The Newtons ring effect being most noticeable when a flat and convex surface need to be in contact as noted by Robert Hooke and then confirmed by Newton.

 

[2WK]

Yea Tri-x is a tough one. I shoot a ton of the Arista Premium or whatever the Freestyle rebranded Tri-x..

Maybe the Arista stuff is more prone to bowing. I dry in a humid bathroom and it stil comes out curly. I always reverse roll it, but that doesn't usually take care of all the curl for me. I have put books on it, with little effect...maybe I'm not keeping them on long enough.

I wish I only used Illford.....it dries so nice and flat. But Delta isn't $2.89 a roll!

 

[Muggins]

At risk of seeming querulous, I didn't say no books (did I? I didn't mean to!) - it's just that they don 't work for me, despite having some very weighty reading matter to hand.

I'd love to be able to adjust my drying heat, but all I have is a hot water pipe just below the darkroom ceiling, which keeps the place a constant not quite chilly but not quite warm either. I guess I could ask for the temperature to be altered, but I can't imagine the college it is in would bother!

I'm off to roll the next six negs into a film canister, and will be back to savour the tangents😀

Adrian

 

[blue4130]

How long are you leaving them under the books? I was having a curling problem, but a week under 50 lbs of books does the trick.

 

[Moto-Uno]

So is it a case of B.S. luck that I've not experienced any Newtonian rings on my scanner
when I lie a piece of thin glass over the film ? Or is there something else going on here that's letting me get good scans ( no post processing at all )? Peter

 

[Muggins]

50 lbs of books

Good grief - I've been using about 5lbs. That's some stack of books! Maybe 5lbs for ten weeks has the same effect as 50lbs for 1 week?😱

Adrian

 

[sevo]

Close enough, Photographic gelatin is 1.44 film can be as high as 1.56 both are as close as need to be for it to work.

AN glass generally is on the top side. You'll rarely encounter Newtons rings on the downward (gelatin-to-glass) side of a negative carrier - even less so with black and white film as the silver will always roughen the gelatin to a degree sufficient to prevent Newtons rings. Usually it is on the acetate/glass boundary as the acetate has a perfectly even finish while the gelatin even of colour film will be microscopically rough (from the "holes" left by the fixed silver crystals and from processing in general) - but at around 1.5, acetate is even closer to crown glass in RI. Still, what really matters is that the separating medium has a RI sufficiently different from each wall of the gap - hence liquid mounting does prevent Newtons rings, while a plate made out of Lanthanum glass or acrylic (or any other unusually high or low RI glass) will not help, there being no solid with a RI anywhere near that of air.

The Newtons ring effect being noticeable when a flat and convex srface need to be in contact as noted by Robert Hooke and then confirmed by Newton.

The surfaces need not be flat and convex if only the distance criteria are met, but that is the one combination where there must be a area where the requirements will always be met, and where the result will be rings rather than banding.

 

[DNG]

I have used Tri-X, HP-5, with no problems..
I think it is the workflow, not the film..

after my final wash, I use 4-5 drops of Photo Flo in 10oz of filtered water for 1.5m...

Hang dry in bathroom I ran a HOT shower for 10m in earlier,
I take the roll off the real, clip top and WEIGHTED bottom,
NO Running fingers or squeegee on the film !!!
2 hours later, I can scan them in strips of 6 with my V700 standard holder
Never a problem with OOF scans.. Center>Corner.

In a hurry, after 20m of hanging, I use a Hair Dryer on high, about a 1.5 feet away in a back and forth motion, from top to bottom.
As I keep the film stretched tight with one hand
Switching sides every 15-20s or so until it's dry.

 

[Erik van Straten]

I use a V600 Epson scanner. You can get from "Better Scanning" pieces of of anti-Newton glass that you can lay on a film strip of 6 frames length. Just lay the emulsion side of the film on the glass of the scanner and lay the anti Newton glass on it. It is heavy enough to push the film flat. I get wonderful scans from it. I use the "zoom" option and scan each time only one frame.
Use the "professional" option and adapt the histogram.

Erik.

 

[rolfe]

I live in the northeast (western Massachusetts) and I use a Jobo Mistral 2 dryer. I just turn on the blower (no heat) and the negatives dry perfectly flat. I think it has more to do with ambient humidity than anything else. Here we generally have mid-level humidity -- won't ever be confused with the southwest US.

 

[Photo_Smith]

AN glass generally is on the top side. You'll rarely encounter Newtons rings on the downward (gelatin-to-glass) side of a negative carrier - even less so with black and white film as the silver will always roughen the gelatin to a degree sufficient to prevent Newtons rings.

That's wrong; film has a coating on the gelatin side called the 'subbing' the silver roughens nothing it is contained in the record layers. The reason it occurs on the base/glass interface is film curves that way.

Usually it is on the acetate/glass boundary as the acetate has a perfectly even finish while the gelatin even of colour film will be microscopically rough (from the "holes" left by the fixed silver crystals and from processing in general)

As stated it normally happens on the base side because that's the way film curves and that's why the base is the contact point.
The statement that the emulsion side is full of 'holes' created by fixer is a new one on me, it may be rougher than the base (it is before processing) and it is wholly incorrect to say this is due to silver 'roughening' the gelatin–whatever that means

- but at around 1.5, acetate is even closer to crown glass in RI. Still, what really matters is that the separating medium has a RI sufficiently different from each wall of the gap - hence liquid mounting does prevent Newtons rings, while a plate made out of Lanthanum glass or acrylic (or any other unusually high or low RI glass) will not help, there being no solid with a RI anywhere near that of air.

Like Newton stated in his address on Robert Hookes earlier work the effect is notices when light moves from a material of a higher RI to a lower one normally through an air gap as long as the two glasses don't have the same RI the effect is easily noticed.
When you wet mount you essentially replace the air gap and reduce interference due to refraction.
As I also stated he (Newton) demonstrated the effect with a convex lens placed on glass (with air gap).

The surfaces need not be flat and convex if only the distance criteria are met, but that is the one combination where there must be a area where the requirements will always be met, and where the result will be rings rather than banding.

They need not be flat and convex, but as I stated this is how Newton demonstrated the effect to the Royal Society as long as there is a contact point...

 

[sevo]

That's wrong; film has a coating on the gelatin side called the 'subbing' the silver roughens nothing it is contained in the record layers.

Believe me, film has a surface texture, partially determined by the silver content. Gelatin as used on film is solid and will not move about laterally, so the removal of the silver salts (and most of the silver) in fixing does have a effect on the local strength of the gelatin. The subbing is there so that there are no bare silver salt crystals on the surface, as these would be subject to mechanical exposure - it is thinner than the emulsion layer, much too thin to cover the effect of fixing on the emulsion.

Get a surface microscope and light at an oblique angle, and look at the emulsion side of developed film! For faster film (or silver rich process film), it is even visible with the bare eye. There used to be a trick to determine the emulsion side on unmarked sheet film by shining light on it against a dark background - as you alter the angle of the light on the emulsion side you'll see a negative reflection from the bare areas changing to a positive scattered from the rough silver-rich areas. From the rear, the reflection phenomenon does not happen at all (the reflection is uniform and not dependent on the image), and the scattered positive is much less obvious. Kodachrome had a bare eye visible relief pattern as well due to depositing dye proportional to exposure. With other colour film it is much more subtle and (if any) only microscopically visible.

As stated it normally happens on the base side because that's the way film curves and that's why the base is the contact point.

No, the AN glass on top arrangement is also used (and needed) for medium and large format film which is gelatin coated both sides and does not consistently curve into one particular direction.

 

[Photo_Smith]

Believe me, film has a surface texture, partially determined by the silver content.

I don't need to believe you! Years of study and research have taught me otherwise. Silver content has no effect on the surface of film. The silver is in the record layers and under that is the subbing and anti static overcoat. Film obviously has a surface texture but it has no bearing on Newtons rings and doesn't change during processing and the silver has zero bearing on that texture.

Gelatin as used on film is solid and will not move about laterally, so the removal of the silver salts (and most of the silver) in fixing does have a effect on the local strength of the gelatin.

The gelatin swells and allows diffusion; actually it does move laterally and gets quite soft, the removal of the silver doesn't effect the local strength of the galatin or cause the surface to change properties.

*The swelling of gelatin is uniform in all directions, and is restrained by the support causing the gel to 'fan' presenting the largest area for the solution to diffuse through the emulsion

The subbing is there so that there are no bare silver salt crystals on the surface, as these would be subject to mechanical exposure - it is thinner than the emulsion layer, much too thin to cover the effect of fixing on the emulsion.

Do you make this stuff up?
The subbing is there to adhere the emulsion to the base, the overcoat is there to protect the gelatin from scratching, most also have antistatic properties and a lubricant (microscopic beads on some films).
It is an water absorbing polymer mixed with a hardened galatin (these are chlorotriazine group and polysaccarides)


Seriously Sevo Newtons rings are viewed in the context of the OP with curved film against a flatter surface-you are free to disagree, but this is the classic way Newton (and Hooke before him) observed the phenomenon.
The brighter rings are caused by the curvature of the film the light passes through, the dark rings being an interference pattern.

It has nothing to do with the silver, and in fact you can easily observe it with plain acetate and glass–no silver needed!!

I think this should be the last post on this diversionary subject people reading will have to make up their own minds.

Perhaps they can remember their teenage physics lesson or can Google™ no further information is needed.
Pax


* G Ender and H Zorn, Photographic Gelatin, Academic Press London, 1972

 

[philipus]

Hi Adrian

I'm definitely no expert, and I'm not a professional photographer either, and to top it all off I only began developing BW during the summer, but fwiw here's what I do and I always get flat Tri-X negs (which, incidentally, is the only BW I use these days).

Once I've washed the film, I remove it from the spiral (I have a 5-spiral tank). Then I immerse the film, which has a slight curl from the spiral, into the tank. Basically I just place one roll at the time like this into the tank and then pull it gently out by one end. I know one shouldn't touch the wet film for risk of, inter alia, scratches but I've actually run the film -- very very gently -- between my index and middle fingers to ensure there's no foam from the Ilfotol and I have yet to see any impact on the films from doing this.

A note: Ilfotol foams a lot if one premixes it and pours it in -- this is likely basic knowledge to all but me -- so one should add it to the water in the tank; still there's a slight risk that the mix foams a little when one runs a film through it like I've described above.

I have a clothes hanger the bottom bar of which I've filled with medium-sized clips like these. I've filled the bar because I want to prevent the films from sliding back and forth and getting tangled when I hang new rolls. On my hanger five films fit with one such clip in between the "active" clips:

At the bottom of each film I add a big clip. This is heavy enough it seems. Then I place the hanger in the shower overnight and the next morning it's all perfect.

Hope it helps
Cheers
Philip

 

[Tijmendal]

Thanks a lot Philip. That sounds helpful. I just bought 80 rolls of Tri-X (Arista Premium that is - just a couple days before they ran out!) and it's what I'll be shooting the next couple months.

 

[philipus]

Glad to help Tijmendal. I hope it works as well for you as it does for me.

cheers
philip

 

[brbo]

I have to use ANR glass on both surfaces of the film. I guess my film arches both ways. At the same time.

Also, I noticed that my home developed film was more prone to NR than that from minilab. But it's been a while since I last used minilab for film developing so I could be imagining this.

Anyway, since this thread is about getting a film to dry flat... Most of my films dry with a heavy arch (Ilford Deltas (do all Ilford films dry flat?) and Rollei Digibase films are exceptions). I can flatten them under books, rolling them with emulsion side out etc. It will be perfectly flat when I put it into the scanner only to arch during scanning.

I tried virtually anything (that was possible in my climate and my equipment). Only thing that seemed to work for me was putting film on the reel with emulsion side out and then developing film like that. The problem is that most of the time I found it almost impossible to put 35mm film on plastic Jobo reels with emulsion side out (heavy abrasion of emulsion on the edges of the film and consequently harder loading) and with 120 film the outer thread would touch the inner leaving ruined film after developing. It does dry much much flatter though.

 

[Kingsfan]

How long are you leaving them under the books? I was having a curling problem, but a week under 50 lbs of books does the trick.

a week? and i thought keeping them under books for like 3 days was overkill! (and i still get curl).

gonna try the reverse roll into empty canister tip next time