Reducing Enlarging Flare

[felipemorgan]

felipemorgan submitted a new resource:

(there was a url link here which no longer exists) - Reducing Enlarging Flare

One of the things you will learn if you attend one of John Wimberley’s printing workshops is the importance of reducing enlarging flare. Enlarging flare is non-image-forming light that reaches the enlarging paper. Enlarging paper reflects a large percentage of the light that falls on it. This means that light from the enlarging lens travels to the enlarging paper and then scatters into the immediate environment and needs to be absorbed,...

(there was a url link here which no longer exists)

 

[Sirius Glass]

I am fascinated by your posting. One thing confuses me though, why and exactly how are hanging by your ankles?

Interested Readers Want To Know!

Steve

 

[Jerevan]

Neat ideas! I have a few questions, though: the velvety flocking paper, doesn't that introduce a lot of dust which may be hard to get rid of, compared to a painted which you can dust off easily? And can you see any differences in the prints you make now, and those made before making these adjustments?

 

[felipemorgan]

Thanks for your questions Jerevan!

I have not noticed any extra dust introduced by the flocking paper. The flocking paper is quite clean as it comes from the manufacturer. If it becomes dusty during installation on the enlarger, then it tends to trap and hold on to that dust. A so-called "lint roller" would be the most effective way to remove trapped dust. And finally, if the flocking paper becomes dusty after being installed on the enlarger, then you have a separate problem of dust entering the darkroom, and that is unrelated to the flocking paper itself, although as you have pointed out it will be more difficult to remove dust from the flocking paper compared to a painted surface. I have sealed off the forced-air heating vent in my darkroom in order to reduce one of the main sources of dust in a home darkroom.

Installing the flocking paper in my darkroom was a part of a group of changes that I made all at once, as a result of my participation in a John Wimberley printing workshop. Yes, my prints are much better after making these changes, but I also changed paper, print developer, stopped underdeveloping my prints and over-taxing my chemistry capacity, started controlling print time for developer temperature, upgraded my negative carrier to multicoated glass, began aligning my enlarger (every time I load a new negative in the carrier), switched to a dichroic head, and made the flocking changes discussed in this article.

So obviously, this is far too many changed variables to allow me to say with certainty that the flocking paper improves my prints. John Wimberley's prints, to me, are as close to perfection as I've seen. I think that part of that perfection comes from his attempts to optimize every part of the image quality chain. The idea to use flocking paper to reduce enlarging flare is his, and I believe it makes a positive difference in print quality, but I can't prove it.

 

[Mick Fagan]

Hmmm, quite interesting.

Looks like you are using an external suck system for enlarger head cooling to reduce vibration caused by the on-board fan, has that made a difference as well?

You mention that you align the enlarger every time you change negatives, I'm not really sure what you mean by this. Alignment to me means using either a specially prepared negative, usually one with lines scratched across a black negative, or using a specialist alignment tool. Would you care to elaborate?

Nice to see someone taking the time and effort to reduce and/or eliminate, darkroom errors.

Mick.

 

[Chazzy]

I'm an obsessive-compulsive, but I would never dream of aligning an enlarger for each new negative.

 

[ic-racer]

I can't combat an enemy I can't see. I have been wanting to test for this and was thinking putting a flashed piece of paper right by the easel border with a quarter on it. I wonder if John gives any good ways to test for this.

 

[felipemorgan]

Interesting questions all!

I am using an external cooling system for the enlarger head ((there was a url link here which no longer exists)). I purchased the head used, and when it came to me one of the foam vibration-damping mounts for the internal cooling fan was broken. So when I turned on the fan, I could feel the head vibrating when I placed a finger one of the extremities of the enlarger head. I do not know how much of this vibration was due to the fan and how much was due to the broken fan mount. So I just dealt with it by building my own cooling system. I would suggest that any vibration that your finger could feel or any vibration that would disturb a glass of water resting on the head is enough to effect print sharpness, but you'd need to test your own equipment. Can you make a print with the fan turned on and the same print with the fan turned off?

I use a laser alignment system to align my enlarger, and because I use a glass negative carrier, the laser reflects from the negative carrier without any special attachments. My procedure is to load the negative carrier, remove the lensboard, align the easel to the negative carrier (I use a homemade version of the Ease-align system to adjust the easel rather than adjusting the negative carrier), then replace the lensboard and align the lensboard to the easel (by securing a small mirror to the lens threads and bouncing the laser beam from that and adjusting the Bes-Align adjustable lensboard). With this system, every time I load a new negative into the negative carrier I can check and adjust the system alignment. It takes 2 or 3 extra minutes each time and is worth it as far as I'm concerned. Especially because I find that the system is often out of alignment after removing the negative carrier, reloading it, and replacing it in the enlarger.

In his printing workshop John Wimberley recommends the following test for enlarging flare: Expose a whole sheet of paper to a Zone V density (test to determine what exposure this is). Leave the paper in the easel and hold a dodging card about 12" above the paper so that it will cover half of the paper when the enlarger light is turned back on. Place a small opaque object like a coin on the shaded half of the paper. Expose the paper, with the opaque object in place and half of the paper shielded by your dodging card, to light from the enlarger for four times your normal print exposure time. Process the paper normally. If you can see where the opaque object was, then you have enlarging flare. ic-racer, I think your test might also be valid. Flashing the paper to Zone V puts it on the steepest part of its HD curve before you do your enlarging flare test, and thus makes it the most sensitive to additional scattered light. Using a multiple of four times your normal exposure tests under worse case conditions like a negative that needs lots of burning, etc.

 

[Simplicius]

Jaysus! after reading that i feel like I should only do my enlarging in "clean rooms" from the electronics industry -- crying now...... because in a clean room I'll look silly in those pull on plastic hats that stop dust from my remaining hair.... where does it end? ..... Epitah on Grave ... "here lies Simplicius. Crap Photographer but may he find the dust free darkroom that obsessed him to death in heaven"

wanders of leaving his intended humour behind

 

[Bruce Robbins]

Do you have any before and after prints showing the improvements you expected? Before going to these lengths I think I'd need some evidence!

Bruce

 

[felipemorgan]

I don't have any before/after prints. I didn't think 6 to 8 hours was much time to invest towards improving my prints, so I just made the changes with the trust that there would be an improvement.

 

[Bob Carnie]

A good way of testing before and after is to get a line negative of various size type made.
Put this negative in the enlarger and make the best sharp print you can.
Then do all the good stuff the OP suggests including painting room black.
Now put the same negative in the enlarger and make the best sharp print you can.

You *will* see significantly sharper and less bleeding type after the work.

We did this with all mural rooms in the 80's as we were making very large prints and every little bit helped.