Topic: C41 processing

[charles binns]

Following on from my earlier thread about streaks on my negatives, I noticed last night that I only get streaks or discolouration on films shot with my holgas.  Films shot with my Mamiya 6 come out fine with no marks at all and all the films are processed together, so I do not think that the marks have anything to do with agitation or temperature etc.

Interestingly, I processed a batch of b&w films with Dixactol for the first time over the week end.  Those films shot with the Mamiya 6 are perfect, but the films shot with a holga have drag marks on them.


Negatives shot with the holga will be underexposed (f11 at 1/100 approx.) compared to the Mamiya negs which will be properly exposed so I am wondering if I shouldn't manipulate either the colour developer or blix times to compensate.

I have read that increasing the development times of the CD will cause colour shifts and I am not sure whether or not increasing the blix time will do anything.

Does anyone have any suggestions or has had a similar experience.  Is there a way to change the C41 process that will produce flawless negatives from my holgas?

To recap, I get streaks or marks on my Holga negatives which are sometimes yellow or magenta.  They look like they are the result of uneven development, or sometimes I think that not all the CD or Blix has been washed off the negatives- though that would leave a residue on the negative which is absent.

[Indofunk]

Are they vertical or horizontal marks? Could they be scratches caused by advancing the film in the Holga?

[charles binns]

Are they vertical or horizontal marks? Could they be scratches caused by advancing the film in the Holga?

]

No - they're not scratches or physical marks.  It's discolouration caused by something going wrong in the chemical process.

[Francois]

Or something wrong with the camera...

[charles binns]

Or something wrong with the camera...

No, it's not that either. I promise you.

[thatguychad]

I don't know how you can promise such a thing when you're dealing with a Holga, which many times (most?) are bought *because* of the strange and random things they do to film, as I'm sure you know.

If you have good negatives out of one camera and weird ones from the Holga and you *know* that the Holga isn't doing Holga stuff, then what did you do differently in the processing?

[charles binns]

Here are two examples of what I'm talking about.

The first is a shot of Stockholm and you can clearly see a yellow streak running down the right hand side of the frame.  In fact if you examine the frame carefully it looks as if there's a stain covering most of the negative.  In my view this is chemical - I originally put it down to bromide drag from inadequate agitation despite my best efforts to agitate properly.

The second is one I posted earlier and shows magenta staining all over the sky.

Looking at the negatives again, I actually realised that the holgas are probably over exposing as the negatives look quite dense.  I'm wondering if negative density is causing this uneven development to show up.

The stains seem to result from uneven development  -  but only the holga shots are affected.  My question is therefore, has anybody else experienced a similar problem when processing their holga shots with C41 and what can be done to solve the problem?

The best possible solution I have found so far is to use a stop bath between CD and Blix but I'd be interested to hear other suggestions.

[Indofunk]

I'm going to go with the "if you use a Holga then you should be prepared for weirdness" camp 

[Adam Doe]

But if the Holga were the cause, wouldn't you expect the same sort of weirdness on each frame, more or less?

[jharr]

Yeah, I think I am in the "that's a chemical stain of some sort" group. Mostly, machine based problems will be reproducible. This different color, different placement business is too weird even for a Holga.

[charles binns]

I'm wondering if the negative density affects the development. And if that's the case would increasing development time help -  even though that might affect colour balance. 

In the absence of any better suggestions, I'll see if adding a stop bath in between the CD and Blix and see if that helps.

[BernardL]

Or something wrong with the camera...
No, it's not that either. I promise you.

How can you state that when you have clear, A-versus-B evidence, as stated by yourself:

Films shot with my Mamiya 6 come out fine with no marks at all and all the films are processed together

So it is something with the Holga camera.

But if the Holga were the cause, wouldn't you expect the same sort of weirdness on each frame, more or less?

Not so. For instance the effect of light leaks depends on how long the film stayed at that frame, sun exposure of the camera, etc.

Or, if light leaks can be excluded, you might consider stress-induced exposure; Film that is bent, crinkled, or otherwise mechanically stressed may show marks as if exposed to light. Is the film advance in your Holga problematic? Did you have a hard time loading ths spiral?

[imagesfrugales]

+1, and don`t forget internal reflections in the film chamber which always look different depending from subject and light.

[charles binns]

If the cause is light leaks, how come b&w negatives processed with Rodinal over several years are pretty much flawless?  The only time I had a problem with b&w was using Dixactol and on those negatives the marks on the negatives are definitely from the development process.

I'm sticking with the fact that the problem is occurring in the development and the two negatives I've posted bear that out, though it's difficult to examine them in any detail on this site.

I've looked at loads of my negatives and the marks are consistent with uneven development and drag.  What I need to work out is why that is happening and how to fix it.

I have a load of colour films to develop over the week end.  Will report back when I have the results.
 

[charles binns]

[
Or, if light leaks can be excluded, you might consider stress-induced exposure; Film that is bent, crinkled, or otherwise mechanically stressed may show marks as if exposed to light. Is the film advance in your Holga problematic? Did you have a hard time loading ths spiral?

I have discounted stress induced exposure - which I do get from time to time and is relatively easy to spot and often leaves a crease or crinkle on the negative.

But that's a separate and luckily minor problem to the one I am discussing here.

[everydaylanre]

I think the discoloration looks cool.  But hey, the 120N was my first film camera* for that reason 

* (technically, my first film camera was a kodak disposable, if you count that)

[charles binns]

I think the discoloration looks cool.  But hey, the 120N was my first film camera* for that reason 

* (technically, my first film camera was a kodak disposable, if you count that)

Hippy!

[Francois]

What I find odd is that it only happens on negs from the Holga...

[charles binns]

And only in C41. 

[jharr]

If the Holga is over-exposing, even slightly, then it could be that the CD is failing in some way that is leaving these marks. I have never tried pulling color film, so can't really speak to any tweaks that need to be done. The shots posted in this thread sure don't look like light leaks to me. Holga light leaks are generally of the "light saber" variety unless they are coming through the red window in which case they are of the "nuclear apocalypse" type.

Good luck with your weekend rolls.

[charles binns]

If the Holga is over-exposing, even slightly, then it could be that the CD is failing in some way that is leaving these marks. I have never tried pulling color film, so can't really speak to any tweaks that need to be done. The shots posted in this thread sure don't look like light leaks to me. Holga light leaks are generally of the "light saber" variety unless they are coming through the red window in which case they are of the "nuclear apocalypse" type.

Good luck with your weekend rolls.

Hopefully stopping the CD will resolve the issue.

What would be really cool would be to mount a holga lens onto my Mamiya 6. I am going to e-mail SK Grimes to find out how much it would cost (if indeed it is possible).

[gsgary]

If the Holga is over-exposing, even slightly, then it could be that the CD is failing in some way that is leaving these marks. I have never tried pulling color film, so can't really speak to any tweaks that need to be done. The shots posted in this thread sure don't look like light leaks to me. Holga light leaks are generally of the "light saber" variety unless they are coming through the red window in which case they are of the "nuclear apocalypse" type.

Good luck with your weekend rolls.

Hopefully stopping the CD will resolve the issue.

What would be really cool would be to mount a holga lens onto my Mamiya 6. I am going to e-mail SK Grimes to find out how much it would cost (if indeed it is possible).

Thats blasphemy

[Francois]

Well, you'd need a shutter first. And then, the Holga is pretty thin so there's the registration distance to deal with.
I know it works with my uber thick Nikon (I have the Holga-N lens) but mamiya 6... I don't know.

[charles binns]

Well, you'd need a shutter first. And then, the Holga is pretty thin so there's the registration distance to deal with.
I know it works with my uber thick Nikon (I have the Holga-N lens) but mamiya 6... I don't know.

Good point, Francois, I forgot the shutter for the Mamiya 6 was in the lens.  What a pity.  I may buy the Nikon lens but Mamiya plus Holga, what a combination that could have been.

[Francois]

The Nikon lens is OK, but it uses a strange soft focus aperture a bit like in the Rodenstock soft focus lenses. While it does produce a nice degree of softness, the aperture has a tendency to show-up when you shoot into the light.

[Photo_Utopia]

When I ran a dip and dunk we had something similar, it was a combination of foam from agitation and low acidity in the bleach (add acetic acid and get some oxygen in it).
Any process defect will be more noticeable in the sky or any area that is higher in density, this is particularly the case with run marks.
I think the camera is not the cause directly, you will see similar if you expose the film the same with the Mamiya or if you get a thin image from the Holga it won't notice so much.
 

[charles binns]

When I ran a dip and dunk we had something similar, it was a combination of foam from agitation and low acidity in the bleach (add acetic acid and get some oxygen in it).
Any process defect will be more noticeable in the sky or any area that is higher in density, this is particularly the case with run marks.
I think the camera is not the cause directly, you will see similar if you expose the film the same with the Mamiya or if you get a thin image from the Holga it won't notice so much.
 

That's very interesting, thank you.  I had read somewhere that I should oxygenate the blix (something I have not done before) and what you say about the acetic acid seems to back up the need to use a stop bath in between the CD and blix.

Will report back once I've processed some films this week end.

[charles binns]

I processed twelve rolls over the week end, all shot with a holga, and added a stop bath to the process, between the CD and Blix stages.  I also aerated the blix.

And it seems to have worked.  The streaks and marks have pretty much disappeared -  there is some very slight streaking on the edges of a couple of the negatives but barely noticeable and probably down to imperfect agitation.  Most negatives though are pretty much flawless.

The only flaw that is apparent on three negatives is a smokey black band  running down the right hand side of the negatives.  Never seen a flaw like that before and no idea what could have caused it.  It's no big deal though as the number of negatives affected is very small and the flaw is easily cropped out in Photoshop.