Knowing what’s right, but getting it wrong – Some silly color problems

Learning involves making mistakes and if there’s one thing I’ve learned by now, it’s how to make excellent mistakes – all the time. Most of them are silly ones, too: I know better, and then I do it wrong anyway. Recently I goofed hilariously badly when working with a batch of ECN2 films. Here’s to show that I’m by no means perfect. Far, very far from it…

Some people like to brag about their accomplishments – I guess I’m the opposite. At least some of the time. And let’s be honest: there’s a lot more failures to blog about than successes, at least in my darkroom practice! Well, maybe not quite. But there’s a lot that goes wrong, and here’s another small selection.

The context is this: there’s this 400ft roll of ECN2 Vision3 250D I purchased earlier this year and that I’ve been snipping 36-exposure rolls off of. I’ve been using this film largely to my satisfaction (surprisingly, in fact), so I also brought along some rolls on a recent trip to Sicily. Back home, I had the task of processing those five rolls of film. At this point, the unique combination of nonchalance and proverbial impatience that I’m suffering from comes in. Cue the issues.

Remjet issues, including sprocket hole offset

Looking out over Taormina towards Calabria. Disregard the funny pink color for a bit; that’s a different issue. Notice the interesting white UFO type artefact top right. Yeah, that’s remjet stuff.

What happens is that during processing, some remjet gunk tends to collect along the edges of the film, including the sprocket holes. If these film edges then happen to come into contact with the emulsion in a different place (e.g. the film curls up when unloading from the spool), the remjet material deposits itself onto the emulsion. Gelatin emulsion proves to be a great match for remjet gunk – the two enter into a very intimate marriage, indeed.

The solution is to prevent the film from curling up as long as any remjet gunk remains on it. The easiest way I’ve learned about so far is to just unspool the film after processing inside a tub of warm water, holding the reel and film underwater all the time. As the film is unspooled, just rub off the remaining remjet between thumb and index finger. It’s really easy and really embarrassing I somehow never thought of this myself. There’s a YouTube video that explains this, but I’ve already explained all there is to it!

Godawful massive fog. Intermittent, though.

This one appears on two of the rolls I processed, mostly at the start of the roll. I.e., the bit that’s the first to go onto the development reel. I used a Jobo 1510 tank and one of those clear plastic (polycarbonate…?) Jobo 35mm reels here.

The probable cause here is fogging due to either the display or a status LED on the darkroom timer I’ve got above my darkroom sink. This is also the place where I spool my film onto the development reels – perhaps not so smart to do this right beneath the timer thingy.

Film loading station. Note DIY darkroom timer/clock and DIY LED lighting.

Previously, I used to just block off the red numbers on the clock when doing light-sensitive work with a fitting cardboard lid that slid over the device. This seemed to work just fine for the most part – except that this time, apparently it didn’t…

So I did some minor tweaks to the darkroom timer. Firstly, I made the lights actually switchable. I can now flick a switch and the display goes absolutely dark. Secondly, I took some black acrylic paint and painted over any status LED I could find inside the device. I built this from ready-made modules and pretty much all of those include little status LEDs to show that power is on etc. Nice for most hobby projects, not so nice in a darkroom. The black acrylic is an easy fix that involves no further hardware modification.

Critical examination of the darkroom situation showed some further issues. There’s an ethernet router in the corner of the room that has an array of blue and green (the horror!) status LEDs. The acrylic trick didn’t work here, so I actually opened up the router and unsoldered all the current limiter resistors for the LEDs. It’s perfectly dark now. The main drawback is that during network maintenance etc., I no longer have indicators that show if a connection is live. We’ll have to live with this, I guess.

Another source of light contamination/fogging turns out to be a more annoying one. Remember those fancy darkroom LED lights I put up last year? Well, they’re really great, but they have one distinct flaw: the don’t go entirely dark. That is to say, it’s really, really hard to see it, even after accommodating to the dark for ten minutes or so, but it turns out there’s a tiny amount of light that leaks from the white LED strips.

How come? My guess is that it’s a natural consequence of the PWM control I’m using for the LEDs. I simply switch them using a low-side N-channel MOSFET (an AO3400 as it happens), which works well enough. Except that these MOSFETs have a leakage current of up to 1uA (even more at higher temperatures). That’s a really tiny amount, but it turns out to be enough to create some visible light spill. Especially the bar over the darkroom sink appeared to suffer from this effect – the other two less so, apparently due to minor individual difference between the MOSFETs used.

Currently I’m testing with the solution shown above. It’s a small (ca. 15x20mm) high-side switch that cuts out the 24V supply to the LED bars whenever there’s no active PWM signal on any of the channels. It’s a relatively easy and non-invasive patch for the electronics of my DIY light modules. So far, it looks like this cuts down the problem massively, although not quite as much as I’d hoped. The AO3407 P-channel MOSFETs I used for the high side switch also have a <1uA leakage current…so maybe I’ll have to resort to a relay instead. But let’s see how it goes with the current package of measures I’ve taken.

Add water to make…

Notice how the bottom strip is much darker than the top one? Right. So that’s a classic mixing error. I can’t recall having made that same mistake earlier, but it sure happened this time.

When processing ECN-2 film, I compound the developer fresh from dry chemicals. I’ve never tried keeping a working solution around for longer than a few hours and frankly, I wouldn’t really trust its longevity, so I prefer to work with the fresh stuff. It takes a bit of work, although ECN-2 developer isn’t a very complicated mixture. The main drawback, apparently, is that this simple procedure can go wrong, although I’ve done it countless times without failure.

What happened here is that I mixed the dry chemistry into approx. 150ml of water. And then, as you perhaps know, there’s usually a line towards the end of a chemical recipe that goes something like “add water to make 1000ml”. In this case, it should have been 250ml I think, but I totally forgot. So I processed both rolls in (1) insufficient developer volume according to the Jobo specifications for this tank and (2) the developer that I did use was far too concentrated.

Turns out the the low volume didn’t do much damage; both rolls came out developed quite evenly. They were just quite different from rolls processed in correctly mixed developer…Especially the orange mask is much denser. Surprisingly, the color balance of the actual images wasn’t all that far off, and the contrast was quite manageable. This could have come out much worse. But it’s not exactly right, either.

The solution is easy, of course. Pay attention, for a change!

One fault that wasn’t mine

All of the above was my own fault. Plain stupidity. But there’s one minor fault that happened somewhere along these rolls of film that wasn’t mine. It’s exceedingly rare, especially with Kodak film, but I’m convinced that this one is an actual emulsion defect:

Alright, it’s kind of tiny, and easy to miss. It’s to the left of my fiancee (yes, we just got engaged about an hour before that image was taken!) Let’s have another look at it, a bit closer up:

A nice blob of excessive density. Don’t ask me what it is, because I have no clue. I’m convinced it’s some form of particulate contamination that somehow found its way into the Kodak coating lines. I’ve got two similar specks a bit further along the same roll of film – and I’m kind of hoping the issue is isolated to just those few frames.

Since it’s really tiny, it’s incredibly hard to photograph – but observing it, it’s something that’s really embedded into the emulsion, or perhaps even underneath it. All I know it’s that it’s not something that attached itself to the emulsion during or after processing, nor is it a bit of remaining remjet. I’ve had all kinds of contamination issues over the years and I know very well what it looks like if random bits of muck (lint, cat hairs, calcium scale, remjet gunk, finger grease, etc. etc.) attach themselves to an emulsion. This is really inside it.

So two or three frames ‘ruined’ (slightly compromised) due to Kodak’s fault. I’ll take credit for the dozens of other ones I lost due to my own stupidity!

2 thoughts on “Knowing what’s right, but getting it wrong – Some silly color problems”

  1. Hello and thanks for some „encouraging“ stuff here, because on my desk are also some holiday rolls of Kodak Vision waiting for development… But color cast, crossed colours and debris are why I shoot film for haha.
    The unremovable remjet gunk in emulsion also happened to me recently – I did some experimenting with reversal development and wanted the silver to be retained in reversal image. So I did first BW dev, then dichromate bleach, then re-exposure, then color dev and fix. The BW dev and dichromate bleach didn’t work quite well with remjet, it stayed there and didn’t want to dissolve and while manipulating with the film it transfered into emulsion like you wrote. And it just stayed there and made spots. The reversal experiment came out quite wrong anyway. I did see some convincing results (vision reversal) at some guy, but he didn’t tell me how he achieved them.

    1. Interesting experiment! I think I have an idea why you ran into remjet problems with your reversal problem. You’d have to look up what kind of binder they use for the remjet, but my guess is that the dichromate bleach may have hardened this polymer – that’s what dichromate can do, especially if exposure to UV happens at some point. It depends on a couple of factors if this was the case, and you’d have to look into the nature of the remjet chemistry insofar this is public knowledge. It’s an interesting angle, for sure.

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