Troubleshooting Ideas

[highkrausen]

My last development yielded some unexplained and inconsistent negatives... looking for some troubleshooting ideas. I'm leaning towards a problem in the equipment or developing, but I can't put my finger on it.

I had 4 negatives (out of a single batch) that came out each differently:
1. black. as if I didn't expose it. it's possible I didn't cock the shutter (doubtful) or something, but I definitely recall putting the dark slide back in on this shot.
2. house (below). Almost looks like a sun flare (this shouldn't have been the case) or light leak?
3. super dark, looks 4 stops under exposed. can barely see in light, doesn't scan.
4. plant on wall (below). Definitely no possibility of reflection. Again, light leak?

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A couple of thoughts:
-#1 and #2 were on the same holder. #3 and #4 were on the same holder
-I am 99% certain my exposures were correct for all of these. After I calculate my exp, I do a digital shot to see how close I am. I learn from the histogram, some times make an adjustment, then take my shot. Lately I've been nailing it, so I'm confident in my technique there
-I am 99% confident my chemistry temp, process, etc. - was as good as every other time.

-I did load these holders in a dark bag in bright sunlight. I would hope that wouldn't be the issue. If so, why the inconsistency?
-I saw a thread from summer on Toyo 4x5 holders/dark slides being milled too thin and people getting blotchy negatives. I have a 8 holders and have other shots that turned out great, so I'm hoping they fixed the issue.

I'm going to reload some different and same holders and shoot some test shots and reproduce my same darkroom technique as a test.

However, curious if anyone with more experience can look at these and tell me where something went wrong.

Thanks!

[Milonian]

The two images you've posted look very like some that I had from a Hasselblad roll film back. I replaced the light trap material and the problem disappeared.
I've seen people advise that you don't fully retract the dark slide but then of course you lose the indicator function and you can't tell if the film in that holder has been exposed.

[Doremus Scudder]

Definitely a light leak.

If you're shooting sheet film in holders first make sure you aren't pulling the spring back away from the rear standard when removing/inserting the darkslide. This is common and results in exactly what you show here.

Also make sure the filmholders are seating properly in the back (could also cause exactly this) and that there are no light leaks between holder and seat.

If that's all okay, then start looking for bellows leaks, holes, cracks in the camera body, etc., etc. The old lightbulb-inside-the-camera-in-a-dark-room trick really helps.

As for the underexposed shots; you may have an iffy shutter. Check it out.

Best,

Doremus

[highkrausen]

Ok cool, agree leaning towards equipment...but also can't figure out why these both appear a stop or two underexposed. That's an easier problem to fix.

Given the location of the leak, would you agree it's likely not from the dark slide "side"...its from he GG hinge side or the hinge of the holder itself?

I reloaded all my holders and will fire some test shots today if I can.

Will report back if I find anything or it just goes away with my "awareness" of it.


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[Peter Lewin]

Agree with Doremus that these are light leaks. Just to expand a fraction on his comment, a good habit when pulling dark slides is to use your other hand to hold the back closed, to ensure that even if you are pulling the slide at a slight angle, you don't open the back a crack, which would cause exactly the leaks you are seeing.

As to your under exposure, again concurring with Doremus - unless you have gotten good results with the same lens/shutter in the past, it is not uncommon for the actual speeds on lenses we purchase used to differ from the "engraved" speeds. You can either experiment via some bracketing or there are some inexpensive apps for checking shutter speed. I have one on my iPad, just happen to be in another room right now so I don't remember the name, but it works by timing the gap between the sound of the shutter releasing and the shutter closing.

[Pere Casals]

some inexpensive apps for checking shutter speed. I have one on my iPad, just happen to be in another room right now so I don't remember the name, but it works by timing the gap between the sound of the shutter releasing and the shutter closing.


Perhaps you are talking about something like that $15 solution:

http://www.ebay.es/itm/Camera-shutter-tester-for-shutter-speed-up-to-1-1000th-for-PCs-and-laptops-/161847764509?hash=item25aee0e61d:g:6N0AAOSwNgxWEWrJ

As Ebay links are volatile (following rules) I write what it is.


It can be found by searching "shutter tester" at ebay.

I consists in a photodetector that pulses to an audio jack, then we can see the signal with any bare audio edition software, like free Audacity, if we plug it to a PC or smartphone device.

There are also $90 standalone devices that shows the measurement...

The fotocell+audio software has the advantage that you see the openning and closing ramps, note that the measurement has to be done by including one ramp in the measurement but not the other, like it is shown here:

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This is the $15 device:

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I'm doing the same but with DIY circuit and an USB oscilloscope (Picoscope)... I find this is very useful as one can see also if speed is always the same or if it varies every shot. Very useful to test vintage gear, also useful to some amateur people, like me, that are making budget kits from ebay low end near trash.

[highkrausen]

I have good results from this lens using the same shutter speeds, so I'm going to make a mental note but temporarily remove that as a problem unless I continue to see inconsistencies. I think the back, holder and dark slide are good starting places to explore an equipment or likely technique flaw.

As I was reloading holders last night I spent some extra time validating that the sheets were in fact in the correct slot vs in the slide's slot. It's possible there was a rookie mistake there as well.

With that all said, I'm not throwing the house pic away. The light leak gives it a creepy, haunted feeling that would be nearly impossible to reproduce. ;)


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[highkrausen]

Might have an explanation on my "under-exposed" shots. I noticed lots of my shots seemed under by a stop too... I am pretty confident in my metering, so caused me to look into my processing.

Ilford HP5+ 400 lists D-76 1+1 @ 68F for 11 minutes. http://www.ilfordphoto.com/Webfiles/20106281054152313.pdf

While searching some sites, I saw lots of people developing for 13 minutes. Also looked at Massive Dev Chart and they have HP5+ D76 1+1 at 13 min!

Am I missing something? Going to give 13 minutes a go with my latest sheets and share back.

[koraks]

The difference between 11 and 13 minutes doesn't account for the total lack of density you describe in your initial post under #1 and #2. Correctly exposed, 11 minutes instead of 13 minutes development time would have produced thin but scannable and printable negatives.