dealing with negative popping

BetterSense · Jan 24, 2016

In my current Omega enlarger, with non glass carrier, my negatives start to go out of focus at about 5-7 seconds due to heat from the lamp. Solutions tried: glass negative carrier (too much dust and Newton rings), very short exposures, or very long exposures. At one point i was exposing prints for 4 minutes and would leave the area while exposing. Results were good as lomg as i focused after the negative stabilized. Most of the time I limit myself to 7 seconds or less which aalso works well as long as i don't have to dodge and burn. What do other people do? Stop down to F22?

Patrick Robert James · Jan 24, 2016

No substitute for a glass carrier. If you have problems with Newton rings you need anti-newton glass on top. Dust problems are a cleanliness issue. Even if you have dust problems, the print is still salvageable. Out of focus prints are not. I have been using glass carriers for two decades now and will never print without a glass carrier.

youngrichard · Jan 24, 2016

I'm with Patrick all the way, except that for 35mm you can get away with glass on top only as in the Leitz V35 neg holder.
Richard

Doremus Scudder · Jan 24, 2016

Heat-absorbing glass between the condenser stage and the negative (or switch to a dichro head..).

Glass negative carrier with AN glass and take the time to clean it.

FWIW, I often print with glass just on the bottom or with a glassless carrier, but my cold light sources tend not to heat up the negative.

Another alternative is to just turn on the enlarger lamp some seconds before exposing (e.g., keep the lens cap on or cover the print with a card) and wait for the negative to stabilize. Then begin your exposure.

Best,

Doremus

Rick A · Jan 24, 2016

I never use a glass carrier, even with 4x5, and haven't had any problems with negative popping. I do heat up my negatives before printing them, I insert into the holder, turn on the light and leave it on while I set up for printing it. I leave it heating for a few minutes usually before I print. If the negative is popping, I don't see it, but always re-check focus just before printing.

bence8810 · Jan 24, 2016

For me I only have this issue with Medium Format so what I do is I won't keep the head on for longer than 20 seconds even while focusing. This keeps me in the safe zone with my enlarger.
My times for exposure are usually 10-20 seconds. I happily stop down to f16 or even 22 if I need to.

Glass carriers are too much hassle for me, really don't like the dust and I don't have the skill to fix a print retouching after wards.

AgX · Jan 24, 2016

BetterSense said:
Results were good as long as I focused after the negative stabilized.

Rick A said:
I leave it heating for a few minutes usually before I print. If the negative is popping, I don't see it, but always re-check focus just before printing.

But focusing on a popped negative can't be the ultimate solution. Unless we got curved-field enlarger lenses.
(Following the concept of those Leitz CF projection lenses.)

David Lyga · Jan 24, 2016

I swear in favor of glassless carriers (and swear AT glass carriers.) Period. Use a heat absorbing glass and chances are you will nevermore have this problem. It is slightly greenish and available from any glass dealer. - David Lyga

Zathras · Jan 24, 2016

Which enlarger, and what kind of bulb are you using? I wonder if you are using a more powerful bulb than you actually need. If you're using a #212 bulb, you would probably be much better off using a #211.

wildbill · Jan 24, 2016

Dichroic head for 4x5.
Dichroic head and glass carrier for 8x10.

dpurdy · Jan 24, 2016

As AgX is saying, when a negative pops it is no longer flat so you will lose some sharpness on the edges. My own technique is to tape negatives down on the carrier. I tape one side and then using the tape for the other side I pull the negative a tight as I can before pressing the tape down. I mostly print 120 and I find this helps quite a bit.
Dennis

ic-racer · Jan 24, 2016

...glass negative carrier...

...i focused after the negative stabilized.

...

Why seeking for something other than the usual known-to-work methods?

AgX · Jan 24, 2016

And what are they?

Gerald C Koch · Jan 24, 2016

Doremus Scudder said:
Heat-absorbing glass between the condenser stage and the negative (or switch to a dichro head..).

+1

Worked well for me when I used a condenser enlarger.

David Allen · Jan 24, 2016

There are two approaches to this problem both of which work well:

Either you leave the enlarger on and let the negative 'pop' whereby it will not move further and then focus and expose your print and ignore all of the advice about edges not being perfectly in focus which is rubbish advice (if you believe otherwise just look at how often people in the past used to dramatically tilt the enlarger easel to achieve correction of converging verticals).
You use a small aperture on the enlarging lens that will overcome any slight movements in focus - which is a great way forward because modern papers are so fast that one MUST use very small apertures

.
Just get on with enjoying your photography - these 'red herrings' come from an earlier time in analogue photography when things were more critical.

Bests,

David.
www.dsallen.de

cliveh · Jan 24, 2016

David Allen said:
There are two approaches to this problem both of which work well:

Either you leave the enlarger on and let the negative 'pop' whereby it will not move further and then focus and expose your print and ignore all of the advice about edges not being perfectly in focus which is rubbish advice (if you believe otherwise just look at how often people in the past used to dramatically tilt the enlarger easel to achieve correction of converging verticals).

You use a small aperture on the enlarging lens that will overcome any slight movements in focus - which is a great way forward because modern papers are so fast that one MUST use very small apertures

.
Just get on with enjoying your photography - these 'red herrings' come from an earlier time in analogue photography when things were more critical.

Bests,

David.
www.dsallen.de

I thought converging verticals has more to do with lack of lens panel rise rather than negative pop.

BetterSense · Jan 24, 2016

I prefer to print at f8 or wider from 35mm because I can see how smaller apertures soften the grain. But it's true that f22 will pretty much cure the problem and is no problem with most papers.

I will try to find some HAG.

Arvee · Jan 24, 2016

David Allen said:
There are two approaches to this problem both of which work well:

Either you leave the enlarger on and let the negative 'pop' whereby it will not move further and then focus and expose your print and ignore all of the advice about edges not being perfectly in focus which is rubbish advice (if you believe otherwise just look at how often people in the past used to dramatically tilt the enlarger easel to achieve correction of converging verticals).

You use a small aperture on the enlarging lens that will overcome any slight movements in focus - which is a great way forward because modern papers are so fast that one MUST use very small apertures

.
Just get on with enjoying your photography - these 'red herrings' come from an earlier time in analogue photography when things were more critical.

Bests,

David.
www.dsallen.de

There should be a 'sticky' that debunks the myriad of myths that are propagated on this website!

fotch · Jan 24, 2016

David Allen said:
There are two approaches to this problem both of which work well:

Either you leave the enlarger on and let the negative 'pop' whereby it will not move further and then focus and expose your print and ignore all of the advice about edges not being perfectly in focus which is rubbish advice (if you believe otherwise just look at how often people in the past used to dramatically tilt the enlarger easel to achieve correction of converging verticals).

You use a small aperture on the enlarging lens that will overcome any slight movements in focus - which is a great way forward because modern papers are so fast that one MUST use very small apertures

.
Just get on with enjoying your photography - these 'red herrings' come from an earlier time in analogue photography when things were more critical.

Bests,

David.
www.dsallen.de

A third way to use a glass negative carrier.

bence8810 · Jan 24, 2016

Where would you put the heat absorbing glass?
My enlarger has a filter drawer - wonder if I could put something in there...

Lucky 90M-D - condenser enlarger.
Thanks,
Ben

Edit: Also - will it not interfere with contrast / tonality etc?

Sirius Glass · Jan 24, 2016

I have a Chromega Dichroic II 5D-XL enlarger and because it has the dichroic head I do not have problems with the negative popping. It sounds like you need heat absorbing glass.

Jim Jones · Jan 24, 2016

The Omega B22 I used for years ran hot and popped 35mm negatives. I would focus after the negative popped, swing the red filter (with an opaque cover) under the lens, insert the paper, and expose it. A variable transformer cut down the voltage when not actually making the exposure. At reduced voltage each enlarger lamp lasted for years. A step-down transformer can be wired as a voltage reducing autoformer to reduce the voltage. So can a suitable resistor or a suitable incandescent lamp. F/5.6 or f/8 was my preferred aperture. Stopping down more began to take the edge off of some grain. If longer exposures are the preferred solution to negative popping, a ND filter under the lens could work.

Doremus Scudder · Jan 25, 2016

A few things.

Do be aware that the depth-of-focus at the negative is much shallower than at the easel. I can tilt my easel severely to correct perspective and still retain good focus, but a misalignment of the negative stage or a severely curled/popped negative will show soft areas even at rather small apertures.

If you're printing at a wide aperture to "soften" the grain, you're likely softening everything else as well!

Heat absorbing glass (or anything, filters, etc.) that go between the light source and the negative will not affect sharpness as long as they are not too close to the negative (i.e., sitting right on top of it).

For smaller prints, smaller apertures are usually alright. The slight bit of degradation due to diffraction from the smaller aperture is usually too small to be resolved at small magnifications. In other words, you can ignore diffraction till you start making larger prints, and then you'll need a larger aperture anyway.

Negative "popping" doesn't always deform a negative; sometimes, especially if the negative is sagging a bit in the carrier, it actually straightens things out a bit. Still, it's better to get the neg as flat as possible in the carrier and avoid popping by keeping the negative cool, one way or the other.

Best,

Doremus

nworth · Jan 25, 2016

I've never had this problem with my Beseler equipment. I did have it many, many years ago with an Omega D-5. Maybe it's the negative holders, although I can't see any reason why. Both enlargers used heat absorbing glass, although the D-5 ran considerably hotter. I think it had a bigger bulb. For the last 15 years or so, I've used dichro heads, which probably also helped.

DREW WILEY · Jan 25, 2016

I gave up on glassless carriers after about a week of trying it. That was decades ago.

dealing with negative popping

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