The Light Farm

Troubleshooting

This has been a lot more fun to put together than I had been expecting. I can wholeheartedly recommend that everyone keep an "oops!" file. Obviously it's educational, but also it's reassuring. A lot of things can go wrong — will go wrong — but more things go right than wrong. That's good, of course, but I'm also coming to realize and accept that all problems are not created equal. Troubleshooting is about more than fixing things. It is also about uncovering potential.

The Art in the Process.

Question: Which is better, an injection molded plastic lawn chair, to all appearances perfect, or a handcrafted wood chair with all the imperfections of real wood? If you answer the wood chair, how many and what types of flaws would you accept? What would you be willing or able to pay the craftsperson? The question could take a hundred forms. Machine knit polyester sweater or hand knit sweater from handspun alpaca? Chicken McNuggets or home pan-fried chicken? The answers aren't black or white. My favorite cookie comes from a factory. (Sorry Mom!)

It is a mixed blessing that handmade silver gelatin emulsions can look perfect. Commercial materials are perfect. Digital? Even more so because we unrelentingly define perfection to fit the technology.

 

These are both contact prints from 5x7 Kodak sheet film. One is on Ilford Multigrade, the other on handmade emulsion coated on the plain commercial baryta paper sold by Photographers' Formulary. They are indistinguishable. A hundred-plus people have held them and could only guess.

OK, so 'perfect' is cool but is it the only goal? Should it even be a goal? Questions and answers of these sort are intensely personal and get to the heart of art. Me? Sloppy technique for the sake of statement isn't in my nature but I've completely lost interest in chasing perfect. I'd like to explore the inherent potential of silver gelatin emulsions beyond recipes and technique. I don't have a clue yet what exactly that will mean for my own work, much less yours, but I can start with a few things that could be considered either sin or virtue.

Halation.
When light bounces off the back of film or a glass plate and exposes a soft halo of light around the bright objects in the picture.

I love halation. I rarely see it as a flaw. When combined with a fine grain colorblind emulsion, the effect can be ethereal. It does have a downside. Halation is related to irradiation, a not-so-nice phenomenon. Irradiation happens when light bounces around within the emulsion layer and degrades the resolution of the image. It can be minimized by avoiding over-exposure.

The photograph is a flatbed scan of an enlargement on Ilford Multigrade FB paper from a handmade Baby Graphic negative (2¼ x 3¼).

More information on both halation and irradiation: here.
And, a technique for preventing halation on glass plates: here.

The Hand of the Maker.

Handcoating produces selvage edges. A factory produces selvages, too. The manufacturer trims them off before packaging. We can do that. Or...not.

The sheet of gaslight paper on the left is larger than my flatbed scanner. You could print an 8"x 10" negative without seeing any white paper. No one would know that it's handmade paper. The trimmed parts needn't be wasted. They can be test strips. All is good. But, what if you printed a suitable negative with different aesthetics? I've sorta, kinda decided that this whole plate (6½" x 8½") onion study doesn't need the corner of the paper for the image. The print is taped to my refrigerator. I'm trying to embrace the concept.

Printing a full plate, edge flaws and all — no cropping — is an option, but that one's a little harder for my recovering perfectionist's soul to embrace! It's a work in progress.

 

Matching Technique to Process.

This plate is too dense for scanning and Photoshop. It would take forever to enlarge. Does that mean it is the wrong exposure? Depends. It works to photograph it on a light table, but what it was made for was carbon printing. It's perfect for that. Know your materials and where you are going with them.

This carbon print was made by Vaughn Hutchins from my 4x5 dry plate. The print quality is beautiful. As with all real prints, its beauty is made for real life — not virtual. Vaughn's negatives are interesting and beautiful enough in themselves to do justice to carbon printing. Puff tried, but there is only so much a Magic Dragon can do.

Selvages — Maybe.
Spots — Not in this life.

Although some artifacts of d.i.y. can be/should be celebrated, there are a lot of things that are just plain ugly. Dust and lint and the annoying poxes and plagues related to coating are by far the most common problems we're likely to encounter regularly. Making emulsions is easy. Baking a layer cake is more complex. But, unless you do all your work in lab cleanroom conditions, you'll see schmutz. Small particles find their way around. They will settle in your emulsion while it is drying. You'll get some on your film or plates when you are loading holders. You'll pick some up outside when you are photographing. Some will settle on drying negatives and paper after you've processed them. In addition, real materials are...well — real. Stuff happens.

Common sense clean work habits go a long, LONG way to solving problems. Everyone has different conditions to deal with, and we all pretty much know how to keep our spaces clean. You don't have to be obsessive compulsive, but there are no two ways about it — clean habits will make life a lot easier. Be especially careful with chemicals. Not out of fear. With very few exceptions (and I don't use them) darkroom chemicals are no more dangerous than common household cleaning products. The problem with letting chemical dust settle in your darkroom is contamination of your recipes and that can suck the joy out of the process really fast.

With that warning out of the way, it's back to spots. Only photographers with a 100% digital workflow can avoid learning to spot.

For information on spotting please go here.

A Catalog of Coating Boo-Boos.

It makes a difference whether we are talking about flaws on negatives or flaws on paper. A negative can be retouched. Usually the print made from a retouched negative will in turn need some retouching but, with a little practice, there will be no evidence of the original flaw.

Dust spots on a print, picked up from the negative during printing, are easily spotted. But, if the flaw is in the paper emulsion, it may be impossible to make it completely disappear. My best advice is to learn to identify coating flaws on the paper before you print and avoid printing on them. Areas of the paper with flaws make excellent test strips or test prints. Actually, as I've gotten better at coating, I've had to use 'good' paper for test prints and that hurts! Welcome the few inevitable coating flaws in every batch of paper.

In the previous link to spotting, the microbubble was on the negative. You can spot those out on the negative and be left with a small white patch on the resulting print to spot out. No problem. Unfortunately, microbubbles on paper aren't as forgiving.

Microbubbles.

A bubble on paper has the same structure as on a negative. It's a crater inside a raised ring of emulsion. Even if you match the density of the surrounding area, you'll be able to see the raised ring in the right light. It's a personal decision whether or not that's acceptable in a finished print. Letting a piece of paper with a microbubble through doesn't happen very often. That was pure carelessness on my part. They are not hard to see under safelight before you print. Microbubbles are rare if you avoid incorporating air into the emulsion before coating. During the ripening stage, stir very gently and slowly.

Blisters.

Blisters can't be seen on the dry paper before printing. It's when the paper gets wet that they look and act just like you'd expect from their name. During processing, liquid get under a patch of emulsion and swells until it detaches from the paper. When the paper dries, the blister flattens out to a shiny patch on the print. It's very obvious in real life and not something you can spot away. The blister on this print was invisible to the scanner. I had to throw a Photoshop marquee around it and push the contrast to full in order to show it here.

Fortunately, blisters aren't a commom problem. Prevention includes cooler processing temperatures, gentle handling during processing, and a hardening fix. It was when none of those steps worked that I discovered the whole lot of watercolor paper I had just started using had faulty sizing. There was nothing that was going to make it work for emulsions. I donated it all to the local school art program. This is where experience comes in handy. I knew there was nothing wrong with the recipe so it didn't take Sherlock Holmes to figure out the problem was with the paper.

 

But Speaking of Mysteries...

This is a paper problem that came and went in exactly half the sheets in one pack of watercolor paper. Long story short, it appears that there had been some kind of contamination along one side of an entire roll sometime in the manufacturing process. I cut each sheet of paper into four smaller pieces to coat, so half were good; half were bad. The problem was absolutely invisible until near the end of the final wash process. I've never experienced the problem since.

Glyoxal Schmutz.

This is a problem that took me a long time to figure out. Glyoxal is an excellent hardener for paper. I wouldn't be without it. But, particulates settle out to the bottom of the bottle over time. Let that happen. Don't shake your bottle! I take up a dropper full from the very top of the bottle and never touch or disturb the junk at the bottom. Problem solved (most of the time). A small glyoxal particle can still sneak in. They are visible on the dry paper before printing. This sheet of paper had a thin patch up in the corner in addition to the glyoxal pox so I used it for a full image test sheet.

Glyoxal particulates repel the emulsion around them clear down to the paper. There is no 'crater rim' of dried emulsion so they can't be confused with microbubbles. Unfortunately, they are easily confused with "repellency" spots. Unfortunate because the solution is very different. A surfactant (e.g. Photoflo) won't do anything to fix glyoxal pox, whereas it's the remedy for repellency spots. For more on repellency spots please go here.

Repellency Spots.

This is from the first batch of emulsion I made at home. It is a catalog in itself of everything that can go wrong. First, it is terribly "peppered" (more on that here [coming soon]). The emulsion was too thin and hadn't been ripened enough for good density. But we're here for the repellency spots. My initial problem was actually glyoxal particulates, but I kept adding Photoflo thinking that would solve the problem. It made the problem worse. Too much Photoflo actually starts to form its own repellency spots.

Take-home lesson? If a "solution" makes a problem worse, it isn't the solution. Look elsewhere. Specifically, a little Photoflo helps with coating on watercolor paper. It isn't as useful (to say the least) on film, glass plates, or glossy baryta paper. Photoflo may actually promote emulsion lifting and frilling when use with emulsions coated on film or glass. If you think Photoflo might be a solution for any spots you're experiencing, start with adding a drop and work up from there one drop at a time. In my experience, though, Everclear (ethanol) is the best surfactant for almost all emulsions. By and large, save the Photoflo for the last negative rinse.

Too Thick. Too Thin.

Beyond problems with the emulsion (and those will be covered in the Emulsion Making chapter) and spots of various forms, the only other likely problem is with emulsion thickness. Think Goldilocks and her porridge. This print has too thin, too thick, and just right. The paper was coated with an emulsion blade. Any blade system (that I've used) starts the coating trail with a thin patch. You can see that when the emulsion is wet, but it becomes almost undetectable after the emulsion dries. Keep a permanent marker handy to your coating station and before you coat the next sheet draw a 'map' of where the good coating starts. When it's time to print, you just avoid the marked areas. With this piece of paper I was too conservative. I should have placed the negative further away from the thin emulsion. It's hard to see from a scan of the print, but there is also a patch of too-thick emulsion mid, upper edge (inside the marked semi-circle.) Thick patches are hard to see when the emulsion is wet, but look a lot more shiny when the emulsion is dry. They aren't technically ugly, but they do look different from the rest of the print.

The real problem with thick patches is that they take much longer to fix out. It's easy to end up with a patch that will turn brown after the print is processed and exposed to daylight. Brown discoloration is the classic result of inadequate fixing.

Paper that is wet-coated with a glass rod ("Puddle Pusher") set to the appropriate height almost never has problems with too thick/too thin (with practice, of course.)

Uncovering the Hidden Potential.

Color Shifts.

Can you see what this print and the one above have in common? This was a test print. I used the rump end of a piece of paper to test exposure for a silvergum K-layer (more on silvergum here.)

I only fixed it for a few minutes — just long enough to inspect it by daylight. I pulled it out of the fix and left it lying on the bottom of the darkroom sink. Over the next couple of hours it started turning a beautiful rosy brown, so I took a chance and gave it a full fix, then washed and dried it. I know there is potential here. Just haven't chased it down yet.

Solarization.

An emulsion that easily solarizes is undesirable. You need to be able to trust that over-exposure will only result in a dense negative. But, there's artistic potential in solarization. (More on solarization here.)

I first encountered solarization problems when I was working on a new recipe that ended up having too much iodide in it. It was super speedy but I thought is was actually slow and kept adding exposure. That increased the solarization. Solarization is a funky phenomenon. It can be partial or complete. It follows exposure. A negative can be only partially solarized in the highlights and normal in the shadows.

I finally pushed the exposure to a completely flipped plate — too thin to be used as-is, but only a couple of minutes with Photoshop turned it into an interpretation I like very much. The day was actually bright and sunny and rather boring. Understanding solarization and direct positive emulsions is another one of those "someday" potentials. There are countless others.

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