HELP! RA4 print problem......

[rustyoldford]

I've had problems the past week whist printing with my Fujimoto CP-31 and Durst M707 enlarger.

Basically I can't get a 'clean' image.
There is always a cast. Its either magenta, or green. There seems to be no clean whites inbetween!

What I've tried..........

-Spending ages in the darkroom trying to filter the casts away.
-New chemicals twice
-extremely thorough cleaning of the printer
-checked that the enlarger's filters are moving ok
-checked for light pollution (none, I don't even use a safelight)
-There is no fogging on unexposed areas of paper either, only casts on teh exposed areas.
-different batches of paper

I'm at the end of my tether!!! Help!

 

[Claire Senft]

Is the processor thoroughly cleaned? Have you printed sucessfully previously with this equipment or are you just starting out? I know when I first started printing color in the 70's I went thru nearly a hundred sheets of paper to get my first good print.

Maybe it would help if you can make a scan of a couple of theses clinkers and attach them. I hate wasting time telling people what they already know but of course bleach fix is extremely contaminating of RA4 developer.

I have quite a bit of experrience printing Ra4 color with a Fujimoto CP31 and it is capable of doing first class work.

 

[rustyoldford]

Yes it is thoroughly cleaned, spent most of yesterday doing it!

I've been producing good prints from this setup for over 3 years now too......

There's nothing much other than a collection of reddish or greenish casts to see from the test prints either.....

 

[Bob Carnie]

Hi there

Is the problem something like this, highlights green shawdows magenta or vise versa with clean paper white around. If so you have a cross curve problem, first off have you tried changing the negative to make sure the negative is not the fault.If so I would agree with Claire that you have a bleach to dev contamination situation. some how the bleach fix is seeping into the developer?
Do you have any equipment in the room with LEDs ,humidifier,radio bla bla bla??
Also look for reflecting objects in the room . Your shirt, posters, cans of air and light leaks around the enlarger.
Also I would highly recommend you check the original chemicals to make sure you are using the right components, dilutions and mixing methods.
good luck

 

[rustyoldford]

Thanks for the ideas guys....

The neg' isn't at fault I've got an old pefect print from which I'm comparing my new rubbish ones with.

As I said there is no light pollution...... (also no fogging on the unexposed areas of the paper).

I have thoroughly cleaned the processor.

Cross curve problem? What on earth is that?!
It doesn't look as exact as "highlights green shawdows magenta or vise versa" as you say, but I can't seem to get the clean white print inbetween the green and magenta prints.

 

[Bob Carnie]

Ok
what exactly do you mean *you cannot get a clean white print between the green and magenta print* are you saying you make a print it is green , then you make another it goes magenta ** sorry I am not getting a clear idea of your problem

 

[rustyoldford]

Yes exactly that. There is no ideal print inbetween the bad ones....

 

[Bob Carnie]

The only thing I can think of is that the magenta dicrohic is slipping, are you going to white light and then back to filter in to focus your image ? or are you touching the magenta dial inbetween prints? If you are try not touching the dials and just make a couple of prints and see if you get two consistant prints.
Sometimes the dichroic filters are loose and any movevement on the head results in an inconsistent pattern of resulting exposures on paper. Colour paper (RA4) is highly sensitive to filtration changes.
Bob

 

[rustyoldford]

I've not been re-focusing or going back to white light between prints, just altering filtration.

I think there may be something in this 'cross curve' idea.....
When I compare some specific areas in the prints they seem too magenta, but looking at the overall print it seems to be too green!

What exectly is this cross curve phenomenon?
How does it happen and how is it corrected?

 

[Bob Carnie]

Before I get onto cross curve I will also ask you, do you have a proper voltage stabalizer on your colour enlarger? if not this will cause you these kinds of problems.
Very Basic Cross Curve Description
When I use to make internegs from slides years ago we were always balancing the film out for cross curve problems, basically the problem is where complimentary colours, green magenta, yellow blue, red cyan, would be present in either the highlights or the shawdow areas of the balanced print and we would adjust the colour and exposure at the interneg stage to correct for this. { we would use a graduated grey background from pure white to black and on some point we would see the cross curve (rainbow) and this would then have to be filtered out.
Please take note this was a specific problem with transparancy-interneg-print problem and was *not* something that we would look for with camera neg-print.

I do not think this is the problem you are having, I really think it is a mechanical , dicroic , voltage or chemical problem.

I was always taught to always move the dichroic dials to my new setting in the same direction every time. these dials are mechanical and with age become a bit wonky. so its something like the old dial locks we used in highschool, unless you came from the right direction each time you would never open the lock. the same is true for Colour manual enlargers, if you do not dial from the same directon you will have trouble getting consistant colour. If you check you will notice some play on the dial or a soft spot , at least I have noticed this with every colour enlarger I have used .

 

[rustyoldford]

Ok, so it doesn't sound like a cross curve problem.

Voltage?
Its going through a durst transformer and timer, that's all. No real fluctuation in exposures ever noticed though....

The dicroics do have a bit of play in them, but only at the extreme ends oif teh scale really.

Chemicals are new, and its been cleaned thoroghly.
I used a dot of washing up liquid, and rinsed it dozens of times after that.
Any recomendations for what to use when cleaning the machine?

 

[Bob Carnie]

I will show this thread to my tech guy here this weekend if he comes in and will fill you in on the cleaners we use ect.
Are you using Kodak ,Fuji, Agfa chemistrys?
Are you using automatic replenishing on the machine or manual?
Is there a long period of time between printing sessions?
Have you checked manually the tempeture of the developer and the bleach fix after the machine has been turned on.?

Immediate colour/density shifts leads me to think : voltage, dichroics, fogging problems.

Slow colour /density shifts lead me to think: contanimaton chemistry, improper mix, insufficient replenishment volumes, variation in chemical tempetures.

I do not think it is the paper as I think you mentioned that you have tried new paper . is that correct?

If you have thouroughly washed the racks , flushed the tanks and recirculation pumps and hoses as well changed the filters, I do not think it is your cleaning proceedures.

Honestly I think it is your dichroics / timer/ voltage/ or plain mechanical fluctuations of the enlarger.

 

[rustyoldford]

Agfa chemistry, mixed carefully, and I've tried two batches of it.

Manual replenishing, but there's not been enough through it to exhaust the chemistry

There can be a few weeks between printing, but this did happen suddenly

Temps seem ok in the baths

Various new papers have been tried....


Its driving me round the bend! Hope it gets sorted soon, thanks for all the help, anyone else feel free to throw in some ideas......

 

[Bob Carnie]

Here is my last thoughts as now I am all out of ideas without seeing the prints.

take the neg out and determine a slight flash exposure with tone.
very slight.
then expose 5-8 sheets one right after the other, do not touch anything but the expose button. process the prints.
if there is any variation it is the enlarger/timer configuration.
If you do not have a densitometer your eyes should be ok.

If there is no shift then :
try this again and adjust the dichroics. if you notice large shifts it would be the dichroics.
good luck and I hope to here how you solve this problem
best regards
Bob

 

[rustyoldford]

Good idea, I'll try that!