How To Ensure Flatness of Negative in Carrier

DF · Mar 18, 2013

Is there a recomended way to ensure flatness of a negative in the carrier? I focus according to the grain focuser - then I move it over abit and the image becomes blury/a tad out-of-focus. I use a top and bottom plate, not glass. What about tape? What kind?

Vaughn · Mar 18, 2013

I am into bondage...masking tape is fine. So is electrical tape, transparent tape, blue-masking tape, gaffer's tape, etc. I apply tension in both directions...negs from 35mm to 4x5. Usually tape down one side and then attach the tape to the other side of the neg and pull the neg tight...then do the same with the long ends of the film.

ac12 · Mar 18, 2013

What enlarger, what kind of head (condenser, color, variable contrast), do you have a glass negative carrier?
And what size film?

If you use tape, make sure you clean off ALL the adhesive. Any left behind if in the wrong place could get onto a negative.
I use goo-gone to remove tape adhesive. But you then have to wash the goo-gone off, so I follow up with 99% rubbing alcohol, then soap and water.
Also if tape is left for too long, it could become heck to remove. I just spent about an hour scraping and cleaning off old masking and gaffer tape from a carrier that I bought on eBay. The carrier is good, the tape I do NOT want.

Glass is the traditional way to ensure a FLAT negative. But then you have 4 additional surfaces to clean and keep free of dust.

Gerald C Koch · Mar 18, 2013

Another oldtimer's trick is to pre-warm the negative by turning the enlarger on and allowing the negative to pop. Then you focus and expose.

Ken Nadvornick · Mar 18, 2013

Everybody works differently, but I use a double-glass negative carrier with an anti-newton top glass for every enlargement, regardless of negative format. This insures absolutely flat projections. Flat enough that they can be used in a pinch for rough enlarger alignment.

The extra dust-collecting surfaces have never been a problem for me. I store the carriers in ziploc bags until needed, and return them promptly. A simple quick spritz of canned air removes any settled dust particles immediately before insertion into the enlarger. And once inserted, the glass surfaces are totally covered and protected from further dust.

The reward for this small amout of extra effort is corner-to-corner perfectly sharp grain in all enlargements that show grain. And I can't remember the last time I had to spot out a white dust shadow from a print.

[Edit: But before worrying about carriers with tape or glass, you must make certain that your enlarger's negative stage is not out of alignment. If the stage is not perfectly parallel with the surface of your easel, and both of those are not parallel with your enlarging lens stage, you will never be corner-to-corner sharp.]

Ken

BMbikerider · Mar 19, 2013

Keeping the negative flat

I use a LPL 6700 colour enlarger and this had serious problems with the negative 'popping' when it got warm - usually after careful focussing. I took a leaf out of Leitz's book which they used on their V35 enlarger and that was to place a glass on the top half of the 35mm negative carrier so that it came into contact with the negative and kept it flat.

The glass is from a 35mm slide mount, using anti-newton ring glass and is only .8mm thick. It is held in place with a strip of double sided adhesive tape on one side only. There is not a lot of extra glass around the edges of the negative carrier to spare (Approx 1 mm) so the glass has to be positioned quite accurately. I can now focus the negative, make the print, remove the negative and replace it with another and be sure the focus will remain the same.

Oddly though, when using 6x6 and 645 negatives in the other carrier, the 'popping' problem doesn't seem to exist!

MartinP · Mar 19, 2013

Assuming alignment is perfect, the answer is glass.

DF · Mar 20, 2013

I'll check for alignment. Now about the glass. Doesn't it degrade the image? Or is it a benefits outweigh risks?

ac12 · Mar 20, 2013

IF the glass is CLEAN and scratch-free, your images will be just fine.
Yes it is another 4 surfaces to clean and keep clean, but the payoff is a FLAT negative, and one less variable to deal with when printing the "perfect" print.
The tradeoff for glassless is, 4 less surfaces to clean, but the negative can bow or pop.
Either choice has trade-offs and is a compromise in something.

For me, my plan is use glassless as normal practice, but to have a glass carrier to use if and when I want/need to. This lets me use whichever negative carrier that I want/need to, rather than be stuck with one type of negative carrier. Example if I have a particularly troublesome bowed/curved negative, I would just swap from glassless to glass, problem solved. Or if I decide later to just go with glass, I already have it.

BTW glass has another benefit...$ You don't need a lot of different negative carriers for the various size films, you only need the one glass carrier.

David Lyga · Mar 21, 2013

My two cents: There are some of us who consider glass to be anathema. I am one of those. I think that the 'bondage boy', Vaughn, has the best answer so far. Tape tension, in conjunction with depth of field (f 8 or less), should do the trick completely. - David Lyga

Toffle · Mar 21, 2013

Interesting to see this thread this morning. Though I have never really found it to be an issue with my negatives, recently I have been shooting some 40+ year old 4x5 HP4, which does seem to be a little more prone to popping. That's the least of the issues with this film though, the biggest being several decades worth of fog. (which I controlled to some degree with 10ml of KBr solution in my developer) Seeing as I shot it all in a home made pinhole camera, I had little expectation of true sharpness. If I return to these negatives in the future, I will look at taping to improve flatness.

Cheers,
Tom

Vaughn · Mar 21, 2013

When I was enlarging 4x5 (glass-less) I use to have to deal with popping. And like it was suggested earlier, I would warm-up the neg by turning on the light for 1 minute before starting the exposure, allowing the neg to pop before exposure. While my initial exposure was usually around 25 seconds, I would often be burning for several minutes and the heat would build up.

Oh, and it is possible to get sharp focus even if the lens stage, negative platform, and easel are not perfectly parallel with each other...however you will get keystoning (not a perfect square or rectangle)!

tkamiya · Mar 21, 2013

Film flatness really isn't an issue unless you are printing with huge magnifications. Going from 35mm to 8x10 or 11x14, you shouldn't see any issues. Your description sounds more like an issue with parallelism between the film stage and the lens stage.

DREW WILEY · Mar 21, 2013

There is simply no substitute for a carrier with glass on both sides. Even cheapie slide projectors had
lenses semi-corrected for film pop. You were supposed to preheat the slides in the tray beofe starting
your slide show. But if you did things the "pro" method and put the slides in glass AN mounts first, you need a flat-field lens instead. Most colorheads generate quite a bit of heat. Cold light less... (duuh,
they are relatively cool). Even a little 8x10 print from 35mm is about a 7X enlargment, so would benefit
greatly from glass sandwiching. I have a friend who prints 6x6 black and white glassless, and can't figure out how the hell he gets away with it.

cliveh · Mar 21, 2013

A glass surface contains dust and imperfections. Two glass surfaces X2. Tape is not necessary, as when you close the negative carrier and insert it in the enlarger (type of enlarger permitting) it holds the negative flat as would tape. I am a great believer in glassless carriers (simplicity of purpose). If your negative pops with heat, then you are probably spending too much time faffing around with unnecessary dodging and shading.

Patrick Robert James · Mar 21, 2013

In my experience there are people who use glass carriers and people who don't use glass that post about the problems they have with sharpness....

PKM-25 · Mar 21, 2013

As much as I tried to avoid it in the past, I use glass carriers, anti-N on top, regular on the bottom. I live in a dry climate and only certain films do not curl and even then, if the frame edge turns down so much as 1/64, it can show in big prints.

And a word about the dust, I find it easier to clean dust off the surface of glass than a delicate neg. I always have spotting to do, but it is no worse than glassless if I stick to my routines with the glass carriers.

I wish I did not have to use them but man, am I glad I have them!

Ken Nadvornick · Mar 21, 2013

Glass negative carriers—and the small amount of extra effort that using them entails—allow me the luxury of converting one more variable within the system into a constant. Thus, one more thing that could go wrong, doesn't.

I have enough to worry about regarding technical issues that I cannot control during enlargement. It would be foolish in the extreme to add to those issues the things that I can control, but perversely choose not to.

It's that simple, really.

YMMV...

Ken

Rafal Lukawiecki · Mar 21, 2013

I'm a glass convert... If I ever think about choosing an enlarger lens, comparing one with another, I just remember advice given by Bob Salomon on LFPF, that the differences between top of the line enlarger lenses become insignificant if you don't use glass. Having said that, I never thought of taping.

Vaughn · Mar 21, 2013

cliveh said:
...If your negative pops with heat, then you are probably spending too much time faffing around with unnecessary dodging and shading.

Ohhh, an arrow to the heart! (or is suppose to be to a kneecap?)

I saw enlarging as starting out with a white piece of granite and then hammering away into its black core with chisels of light! I would lay down a slightly light general exposure then emphaize the shape of the light over there, keep the viewer's eye from drifting over in this direction, even out the sky perfectly, and dance to the light fantastic! Spend 10 to 12 hours and 10 pieces of paper to get three perfect identical prints...so much fun! Working with 16x20 paper gives one so much real estate to play with! I would just use the initial time (around 25 seconds at f11 or so) and keep hitting the print button, doing all the burning in the 25 second intervals...two hit of the button for this area, maybe three for around this area, etc. I think the longest was about 15 minutes of doing this on a print.

Then I'd process the print thru the fixer and take the print out into the light and and study it for 10 or 15 minutes -- perhaps one more push of the timer button in this area, three over here, reduce it by a half over here...

Now I spend all that fun looking for light on the landscape that does the same thing with straight contact prints in alt processes.

But the fun I had with images like this 16x20 (from 4x5 neg):

Patrick Robert James · Mar 21, 2013

Dust is generally a non issue for me as well. Occasionally I will have to remove a neg from the carrier to eliminate some dust, but it doesn't happen very often. If you are using a condenser enlarger dust may be more of a concern. Dust on the outside surfaces of a glass carrier will not show up in the print.

The added benefit to using a glass carrier in an aligned enlarger is the lens can be used at its optimum aperture, or even wider, which can make a big difference at times depending on what enlarger you are using and how bright your light source is.

There are also masking benefits to using a glass negative carrier. Frosted mylar can be taped to the top and penciled in for dodging. Works great.

All in all, I don't know why anyone would want to avoid using a glass carrier.

Newt_on_Swings · Mar 21, 2013

If your enlarger supports glass carriers you should be using them. For awhile I didnt and thought 35mm was fine, and because of laziness only used the glass carriers for 120 film, but there is a difference in higher magnifications and in the corners, even if you think your negatives are dried flat. I always have a brush on hand for it, and as long as you dont leave smudges from finger oils they are easy to use. Depending on your enlarger type you can probably make your own glass carriers to fit. I have made my own in the past that have worked fine.

tkamiya · Mar 21, 2013

Michael R 1974 said:
That's simply not true. Negatives can easily pop or warp visibly out of focus for small magnifications.

It hasn't been a problem in MY darkroom. I use an Omega D2 with 75watt bulb. I leisurely focus my image then touch up before making every print. Perhaps my habit of taking a while to focus is pre-heating the neg? I had some intricate burning done with up to 3 minutes exposure in 5 minute span. (35mm to 11x14) No problems.

DF · Mar 22, 2013

I'm not doing anything larger than 8"X10" - the image is actually 6"X9".

Simon R Galley · Mar 22, 2013

Glass, I would never use tape on a neg.

Simon ILFORD Photo / Harman technology Limited

How To Ensure Flatness of Negative in Carrier

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