RA4: Red Mist

pentaxuser · Sep 16, 2017

Roger, wasn't it you who needed 130M plus the additional 40M and Y lever to cure the red cast? I thought that max filtration plus the lever had cured the problem but it seems to have arisen again. I was amazed that any print needed max filtration when you reported " the cure" of max filtration. Now that even max is giving a red cast then I suspect that despite your belief that everything is working as it should something is seriously wrong. What safelight are you using for RA4?

I once got a reddish cast in one corner of the print and discovered it was the "glow-in-the-dark" tape I had used to measure the cuts I needed to make 5x7 prints from 8x10 sheets. The safelight, a DUKA, was OK but the light was strong enough to light the tape which was emitting the wrong light wave close to the paper.

I am not saying this is your problem but I am saying that a light issue may somehow lie at the root of the problem

pentaxuser

Roger2000 · Sep 16, 2017

Hello again!

Alack, I don't use any form of lighting for colour work, all is darkness in there. I even taped over a tiny LED on the other side of the room but it made no difference.

I'm stumped. New enlarger?

Photo Engineer · Sep 16, 2017

Contamination of the developer with blix can cause red images.

PE

Neal · Sep 17, 2017

Photo Engineer said:
Contamination of the developer with blix can cause red images.

PE

I have done that.

Roger2000 · Sep 17, 2017

Interesting. Would the contamination cause a red stain on the paper or a red colour cast in the image itself?

In this case, the paper is coming out white, but the image itself has a red cast.

Bob Carnie · Sep 17, 2017

could you post image with white borders and red cast.

pentaxuser · Sep 17, 2017

Roger if the max filtration plus the lever cured the red cast problem but it has re-appeared, it might help if you can clarify what if any differences there have been since the recent cure and the new red mist.

Currently there appears to be nothing wrong but clearly there is. It looks to be light related but I think you have said that you can see the colours change on the easel as you dial in Y and M and can then see another change when you swing the extra Y and M lever. Is that correct? Is there any way you can check that the Y and M filters move all the way i.e. do not stick at a certain point despite the dial still moving

pentaxuser

Roger2000 · Sep 17, 2017

Hello all,

Thank you once again, I do appreciate your comments.

To answer pentaxuser, there wasn't a cure. The last time I used the enlarger, a couple of weeks ago, RA4 prints on Fuji were coming out red on max magenta filtration. Likewise, multigrade prints were coming out with low contrast. Both these happenings point to a problem with the magenta dial. However, when I rotate the dial you can clearly see the magenta filter getting stronger and weaker accordingly.

I've since changed bulbs and opened a new roll of Kodak RA4 paper and the problem remains.

The fact that there's a problem with b/w and colour suggests that the enlarger or bulb is the problem.

Until recently, the enlarger produced good colour and contrasty b/w.

Photo Engineer · Sep 17, 2017

There could be a heavy blue or cyan filter in the beam. Color paper is balanced for tungsten, and appear red if exposed to daylight. That is the only problem that can cause red color images and low contrast B&W prints with white borders.

Look on the lens or behind it for something.

PE

Roger2000 · Sep 17, 2017

Thanks Ron - that sounds very plausible, and would explain why the problem is affecting both colour and B/W, for which I'm using different paper and chemicals. I will investigate for any stray light.

pentaxuser · Sep 17, 2017

Roger2000 said:
Thanks Ron - that sounds very plausible, and would explain why the problem is affecting both colour and B/W, for which I'm using different paper and chemicals. I will investigate for any stray light.

Let us know what you find. I have a Durst 605 and cannot imagine how stray cyan light can affect the image unless you raise the RA4 paper to the level of the negative carrier during the exposure where a little light escapes. The rest of the time the enlarger light would be off, wouldn't it?

pentaxuser

maxdorsogna · Feb 11, 2021

pentaxuser said:
Let us know what you find. I have a Durst 605 and cannot imagine how stray cyan light can affect the image unless you raise the RA4 paper to the level of the negative carrier during the exposure where a little light escapes. The rest of the time the enlarger light would be off, wouldn't it?

pentaxuser

Roger2000 said:
Thanks Ron - that sounds very plausible, and would explain why the problem is affecting both colour and B/W, for which I'm using different paper and chemicals. I will investigate for any stray light.

Roger2000 did you ever manage to find the culprit? I am strangely experiencing exactly the same 'red mist' issue. I've tried to eliminate all variables and am stumped.

pentaxuser · Feb 12, 2021

maxdorsogna said:
Roger2000 did you ever manage to find the culprit? I am strangely experiencing exactly the same 'red mist' issue. I've tried to eliminate all variables and am stumped.

We haven't seen Roger 2000 since Nov 2018 so you may not get an answer of any kind far less one that will help you. I do hate it when an OP just disappears without telling us what happened when we devoted a lot of time to help him but so be it

It might help if you can confirm that your red mist is similar to Roger's red mist as far as you can tell and what of the suggestions we made to Roger have not worked for you either

Thanks

pentaxuser

maxdorsogna · Feb 12, 2021

pentaxuser said:
We haven't seen Roger 2000 since Nov 2018 so you may not get an answer of any kind far less one that will help you. I do hate it when an OP just disappears without telling us what happened when we devoted a lot of time to help him but so be it

It might help if you can confirm that your red mist is similar to Roger's red mist as far as you can tell and what of the suggestions we made to Roger have not worked for you either

Thanks

pentaxuser

Yep, can imagine your frustration that Roger 2000 disappeared. You all had some very thorough analysis by the looks of it. PE's advice is of course, second to none as always!

As for my own sorry saga - alas, I have indeed tried many of the same remedies you had recommended to the absentee OP to no avail. Am at the end of my tethered as I have printed vast quantities of RA4 in the past - primarily through tabletop RT processors such as converted the Durst RCP20/40 range.

To break it down simply, here in the UK I am printing Portra 400 (color) 6x7 negs at home through an LPL C7700 Dichroic enlarger and processing (aged) 8x10" Kodak Endura cut paper sheets via a Nova Quadmate Heated 4 tank 12x16" Processor, using the lowest minimum settings on my Duka 50 safelight (bounced) as I find these Nova Deep Tanks to be slippery bastards in total darkness.

The resulting prints themselves are incredibly red (and often magenta in nature) despite base filtration and are bizarrely immune to filtration - even at maximum settings of 170, 230 Magenta, and Yellow respectively.

A single sheet of unexposed Kodak paper came out without any visible color fogging, just creamy base whites due to age, however, and after thoroughly inspecting my enlargers mixing box and dichroic filters today they seem to be moving fine. The RA4 chemistry was also run 1:4 (400ml Adox -1600ml water) in both 2L capacity tanks of the Nova as per Adox's instructions.

Chemistry has been replaced (fresh Adox RA4 kit) and the paper supplier has shipped me another box of aged (but hopefully useable for test purposes) Kodak Endura cut sheet paper. Could this be caused by the safelight bouncing off the purple-colored bathroom walls? An invisible light leak perhaps? I have masked/taped up all other stray light sources, tried various perfectly exposed negatives.

Can an old enlarger lamp or my steel enclosure Schneider-Kreuznach f/4.5 105mm lens be causing extra cyan/green light on these prints somehow? I've got a new 100W/12V bulb on the way.

I am afraid I am at a loss at this point... Any/all advice much appreciated.

Cheers,
Max

maxdorsogna · Feb 12, 2021

pentaxuser said:
We haven't seen Roger 2000 since Nov 2018 so you may not get an answer of any kind far less one that will help you. I do hate it when an OP just disappears without telling us what happened when we devoted a lot of time to help him but so be it

It might help if you can confirm that your red mist is similar to Roger's red mist as far as you can tell and what of the suggestions we made to Roger have not worked for you either

Thanks

pentaxuser

Forgot to mention, I also have a fresh box of Fuji CA stock arriving in the next few days. I've never known aged RA4 paper to be completely unresponsive to filtration like this though? My only other theory is that the old bathroom fluorescent ceiling lamp could be invisibly outputting some light, even after it's off to the naked eye and fogging that way.

A real head-scratcher this one

dkonigs · Feb 12, 2021

Speaking of "red" artifacts, there is something I've run into. Its probably useless information on this specific subject, but I might as well share it anyways.
When I cut test strips of RA-4 paper and leave them sitting in a paper-safe in my darkroom for a long time, then use them, its not uncommon to have random red splotches on them. Its weird enough that I've questioned my test strip jig/process, but I've never seen this issue with B&W.
Meanwhile, my actual stock of RA-4 paper (that's kept in the refrigerator when not in use) never has these problems.

So I'm thinking that either temperature/humidity is playing a factor, or there's some wavelength of light that the paper safe isn't 100% opaque to, that color paper is sensitive to, which simply accumulates over time.

pentaxuser · Feb 12, 2021

Just to be clear, max. There was a time when you were able to print RA4 without this problem? If this is correct then what has changed since then. It sounds as if the paper has changed and you are experiencing the problem since using cut Endura paper If so is this new Endura that has been cut for you and if so by whom? Since you have used cut Endura has it all been from the same source and has all of it exhibited the red mist?

In summary the only thing that appears to have changed when the red mist appeared is the paper. If the cutter uses safelight then it is possible that this has contaminated the paper. In my early days if RA4 I used to use so called luminous tape to help me see where I needed to place the paper and I got a pink/red blob on the edge of the paper where the light emitted by the tape was enough when the paper passed over even a few inches away got affected.

I think you need to ask questions of the cutter about the paper and in what conditions it is cut, assuming this is possible and always assuming that the cutter will be honest with his.her answers

pentaxuser

eddie · Feb 12, 2021

maxdorsogna said:
My only other theory is that the old bathroom fluorescent ceiling lamp could be invisibly outputting some light, even after it's off to the naked eye and fogging that way.

This is a real possibility. Fluorescent afterglow can last minutes, even after it no longer appears to the naked eye. I only use mine for darkroom cleaning and set up. I then wait at least 10 minutes after I've turned them off before opening any light sensitive materials.

koraks · Feb 12, 2021

maxdorsogna said:
bizarrely immune to filtration - even at maximum settings of 170, 230 Magenta, and Yellow respectively.

Sounds like the filters aren't in the light path. It's a common user error with Durst enlargers where the lever that holds the filters out of the way is left in that position. I'm not familiar with your enlarger, but have you verified this? Of course if you see a visible change in the color of the light on the base board when making big filter changes (>20cc or so), this shouldn't be the problem.

maxdorsogna said:
Can an old enlarger lamp or my steel enclosure Schneider-Kreuznach f/4.5 105mm lens be causing extra cyan/green light on these prints somehow?

Realistically, no, not to the extent of the problem as you're describing it.

I've got a new 100W/12V bulb on the way.

It won't solve your problem, but there's nothing wrong with getting a fresh bulb after many years.

eddie said:
This is a real possibility. Fluorescent afterglow can last minutes, even after it no longer appears to the naked eye. I only use mine for darkroom cleaning and set up. I then wait at least 10 minutes after I've turned them off before opening any light sensitive materials.

Don't know about that. I've printed lots with my previous CFL lights in the darkroom (currently use LED) and despite the apparent afterglow, I never noticed any fogging as a result of this. I'm very skeptical of the notion that invisible afterglow would cause fogging of RA4 paper.

maxdorsogna · Feb 12, 2021

pentaxuser said:
Just to be clear, max. There was a time when you were able to print RA4 without this problem? If this is correct then what has changed since then. It sounds as if the paper has changed and you are experiencing the problem since using cut Endura paper If so is this new Endura that has been cut for you and if so by whom? Since you have used cut Endura has it all been from the same source and has all of it exhibited the red mist?

In summary the only thing that appears to have changed when the red mist appeared is the paper. If the cutter uses safelight then it is possible that this has contaminated the paper. In my early days if RA4 I used to use so called luminous tape to help me see where I needed to place the paper and I got a pink/red blob on the edge of the paper where the light emitted by the tape was enough when the paper passed over even a few inches away got affected.

I think you need to ask questions of the cutter about the paper and in what conditions it is cut, assuming this is possible and always assuming that the cutter will be honest with his.her answers

pentaxuser

Thanks all for all those prompt and detailed responses to this with a view to helping me nail down the issue. Good to know the lens probably isn't a factor in this. To answer a few of your questions, firstly, I was mainly referring to my experience and general familiarity with RA4 processes - I have had several different colour darkroom setups but this issue is specific to my most recent one. I have checked the mixing box and filter 'array' (?) multiple times but they seem to be well within striking distance to the light path and I can sight visible changes to output light of 20cc + across respective colour channels on the baseboard so can probably rule this out. Image attached so you can gauge the severity of the issue. Excuse the lousy easel work and reversed 120 neg - hurried and frustrated hands.

I will toggle the White light lever again on the side with my enlarger top plate off to see if the mechanism is doing its job, as far as I can tell there's nothing obviously wrong with the LPL. They're middle of the road enlargers compared to say an Omega or De Vere but competent nonetheless. Have successfully run a lot of RA4 through the C7700s in previous darkrooms without issue save for a Newton Ring here or there prior to investing in the AN glass.

I am hoping that moving from bathroom to kitchen (far more space = less stress for me logistically, and neutral wall colour) could be of some nebulous advantage in the long run but we will see.

Failing that, I can only assume that the age and base fog on the Kodak Endura is causing this filtration mayhem. Is it possible for 8-10 year old paper stock to just 'brick wall' and cease responding to filtration entirely though? I've never seen that before and have printed on quite a bit of slightly older Kodak stuff as I prefer its thickness, D-Max etc.

Anyway, I live in hope...

maxdorsogna · Feb 12, 2021

Multiple darkroom setups in a variety of different locations*, that is.

I should also mention, there are no overhead fluorescent lights in my larger kitchen space, so that'll be good in eliminating the afterglow theory too. Just the challenge of light proofing it all tonight to make it a workable alternative space.

koraks · Feb 12, 2021

maxdorsogna said:
I've never seen that before and have printed on quite a bit of slightly older Kodak stuff as I prefer its thickness, D-Max etc

Me neither, although I've only printed on horribly old and fogged Fuji paper, apart from fresh rolls. It still responded quite adequately to filtering though. However, the old paper is a liability for sure. I'd wait for the fresh stuff to arrive to at least remove that factor from the equation.

pentaxuser · Feb 12, 2021

I may not have noticed you saying this but as I asked: Have you only used once source for your cut Endura and has it always exhibited the red mist.? If the Fuji you are about to get is from the factory so to speak then this will be the real test. In fact given that you appear to have ruled most if not all of the other causes it might be as well to wait and try the Fuji and then let us know if that makes a difference

If it does then it clearly is the paper. What is the source of this paper. Is it for instance from an e-bay source that cuts his own paper and sells it Is it definitely fresh Endura and have you any idea under what facilities the paper is cut?

In the old days you'd have known several RA4 printers through a photography club or a local shop that did RA4 printing and asked some to use one of your cut sheets to see if the same problem that you have arose with them. Sadly those days have gone

pentaxuser

eddie · Feb 12, 2021

koraks said:
I've printed lots with my previous CFL lights in the darkroom (currently use LED) and despite the apparent afterglow, I never noticed any fogging as a result of this. I'm very skeptical of the notion that invisible afterglow would cause fogging of RA4 paper.

I can't speak to CFL bulbs. My experience with fluorescent tubes showed exposure to both film and paper up to 5 minutes after the lights were turned off. I doubled the lights off time to ensure no damage to the materials.

maxdorsogna · Feb 12, 2021

Yep - the Fuji (factory fresh stock from Firstcall Photographic here in the UK) arriving Monday will certainly help with ruling out the last variable in this saga. Both paper stocks were purchased from a (100% rated) eBay seller who assured me that the Kodak Endura, cut fresh from the factory some years ago, had been stored adequately and frozen ever since. As we all know though, this is running a risk of sorts to begin with, as even freezing won't stop photosensitive materials from aging to a degree though. Curiously yes, both batches exhibiting the heavy red fog were from the same seller.

My only other thoughts are some weird chemical residue in the Nova purchased secondhand (though I cleaned, flushed, and dried it and used Steradent tablets in the tanks), hard UK water contamination (?), or all of the ADOX RA4 batches somehow causing this at the chemical level. I wonder if anyone in these forums has had recent success with their current 2-part RA4 kit?

I purchased this small footprint kit largely to test my set-up for quality prior to investing in more industrial Kodak RA4 chemistry from AgPhotographic here in the UK as my printing quantities increase.

RA4: Red Mist

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