Clear/white "blotches" visible in skies / RA4 process

[ste976]

hello,
any idea about what could cause the white stains i get which are visible in the skys?
if i repeat the print sometimes they are there, sometimes not. i attach 3 prints where they can be visible with different degree of intensity.

background information.
i print with drums (durst codrum 205, 10x8 inch print, i have a few of them), at 35 degrees C, single use (so , no possibilities of chemical contagion).
steps are:
1) pre wash (to heat paper)
2) develp 45 secs
3) stop bath 25 secs (2% acetic acid) and 20 secs water to rinse
3) bleach 45 secs
4) wash

use bellini ra4 chemicals
i pour 50ml and agitate with durst comot (levelled). i got the stain even if i pour a bit more of 50ml

i already blackened every light that comes from the sides and back of the enlarger.

i print with a durst modular 70 colour head, mainly 6x7. i use a 80mm rodenstock componon-s which is supposed to be correct lens up to 6x7.
i imagine if the problem was the enlarger/light/lens should it be in any print?

i use an easel, which i cleaned well, and if it is the easel i should always get the stains i think

i did cut the paper by myself. i was thinking maybe fingerprints, but i did use gloves, and the "stains" don't' look like fingerprints. or they do?

the other thing i was thinking could cause the stains is maybe light leaks from some of the drum i use. but do they look like leaks? stains should be darker not clear if it was ligh leak? and i did get them even if the sky was toward the bottom of the drum (not the lid) .

any suggestion about where to look and how to solve the problem?

thanks a lot
stefano

here some print details where the problem is evident. stains are not in the same exact spot from one print to another. sometimes problem does not appear.

 

[ste976]

i realized that stain maybe are not so easy to spot from the scan if you dont know where to look. the stains are quite big. so now i post the second print with circles around the main stains and then without the circles so you know where to look for the stains

 

[koraks]

i pour 50ml and agitate with durst comot (levelled). i got the stain even if i pour a bit more of 50ml

That's pretty minimal. Try 100-150ml and see how it goes.

As always when someone uses drums for RA4 development, I recommend doing a session in trays at room temperature instead and then see if the problem goes away. This will help determine if the problem is indeed associated with the (in)correct use of drums, which I think is the case here, as it looks like incomplete and uneven development.

For room temperature RA4, use a flat-bottomed tray only slightly larger than the paper size you're printing on, and use sufficient developer to entirely cover the sheet with some room to spare. A depth of 5cm or so is sufficient. At room temperature, start with a development time of 2:00-2:30 and adjust to taste based on some strips that are entirely black. With the chemistry I use (Fuji minilab) I develop for 90 seconds, but I think the Arista will take a little longer.

 

[ste976]

all right, thank you. i will try to use 100 or 150 ml.
i can't at the moment do a session tray because darkroom space is too small.

i used to print with the durst drums a few yeas ago, if i remember well i was using 50 ml (that is what durst codrum 205 suggest to use) without any problems. but maybe i don't remember well and i was using 100ml (definetely not 150ml)

i'll let you know if using more chemistry solve the problem. but i guess that if the look of the stains is the one of incomplete and uneven development, that could be causing the problem

 

[mshchem]

Also, the white specks and lines could be lint on the paper when exposing

 

[ste976]

Also, the white specks and lines could be lint on the paper when exposing

thanks, yes maybe i just have to clean a bit better the negative for more specks. but that is not bothering me at the moment, i know the cause. i have more troubles with those big "clear" stains

 

[brbo]

Do you pre wash?

 

[DREW WILEY]

Sometimes a few drops of chem don't get fully rinsed out between steps, clinging to the rear cap of the drum, or perhaps inside the rim. For that reason, I introduce an optional brief but generous water rinse step between the Stop and Blix phases.

The other potential problem, already mentioned, would be insufficient solution volume.

I wouldn't mess with trays unless you have very good ventilation across the sink, drawing the fumes away from you. One can become sensitized to RA4 chem.

 

[ste976]

Do you pre wash?

Hi. Yes i do prewash. 35 degree C water for 45 seconds I introduced pre wash because i read here that it can help. But it did not solve the problem

 

[ste976]

Sometimes a few drops of chem don't get fully rinsed out between steps, clinging to the rear cap of the drum, or perhaps inside the rim. For that reason, I introduce an optional brief but generous water rinse step between the Stop and Blix phases.

The other potential problem, already mentioned, would be insufficient solution volume.

I wouldn't mess with trays unless you have very good ventilation across the sink, drawing the fumes away from you. One can become sensitized to RA4 chem.

I have a few drums so always wash them well and leave them to dry on open air. I am preatty sure the problem is not there.

To try to solve the problem i have introduced already a stop bath and rinse between develop and bleach. It did improve some other problems, maybe reduced a bit this "clear" stains problem but it did not solve it.
I was doing 30 seconds stop bath and 15 seconds rinse with just water. Looks enough? I can try to add more water and do longer rinse between stop bath and bleach.
But 30 seconds stop bath and 15 seconds rinse with water should be enough to prevent developer enter the bleach?

And i also will try to use 100 ml and not 50 ml during all the steps

 

[koraks]

But 30 seconds stop bath and 15 seconds rinse with water should be enough to prevent developer enter the bleach?

That's not really a concern, developer contaminating your bleach. As long as it's limited to a few drops, nothing to worry about.
The other way around is a massive problem, but that's not what you're battling against currently because the nature of the problem would be different. You'd be struggling with weird cyan blotches and/or streaking.

If you can't or won't try trays, try the simple 'fix' of just developing longer. If you're doing 45 seconds now, try 60 or even 75 seconds. Within a reasonable degree you can extend development without much effect since RA4 is essentially a develop-to-completion process. There's a decent chance your problem will go away since it seems to be related (to my eye at least) to locally incomplete development due to uneven wetting of the paper during the first stage of development. With a very brief development time, this will become a problem.

@DREW WILEY may chime in on this but as I recall he runs the process at 30C with longer development time as well.

 

[ste976]

Thanks a lot. I will try to extend developing from 45 seconds to 60 or 75 and to use 100 ml instead of 50ml. Hope this will solve problem.
Unfortunately tray development is not an option at the moment

 

[Ben 4]

That's pretty minimal. Try 100-150ml and see how it goes.

I suspect this is the right diagnosis. Back when I was developing RA-4 in drums (Unicolor, so not the same as yours), I believe I settled on 90ml as the minimum quantity for the 8x10 drum.

 

[pentaxuser]

I have searched the internet and nowhere can I find the amount of print developer for an 8x10 Durst 205 Codrum I found a drum on e-bay and while the outside of the drum specifies amounts for negatives and both Cibachrome and Kodak reversalI coudn't work out the amount needed for an 8x10 print

As it is meant for 8x10 negatives one might assume that the amount for negatives apply and it does say 50ml. So on that basis the OP's use of 50ml might be right but it might be as well if the OP were to try and discover the amount, if he can

pentaxuser

 

[ste976]

I have searched the internet and nowhere can I find the amount of print developer for an 8x10 Durst 205 Codrum I found a drum on e-bay and while the outside of the drum specifies amounts for negatives and both Cibachrome and Kodak reversalI coudn't work out the amount needed for an 8x10 print

As it is meant for 8x10 negatives one might assume that the amount for negatives apply and it does say 50ml. So on that basis the OP's use of 50ml might be right but it might be as well if the OP were to try and discover the amount, if he can

pentaxuser

I will do a test in a few days. The durst codrum 205 drum says 50 cc for negative process.
I used them a few years ago without a problem but I dont remember if it was with 50 or 100 ml. At that time i was using durst coterm to heat the chemicals. Since the small jars in durst coterm are 100 ml it might be i was using 100 ml.
50 ml could be just enough, thats why i get correct print some of the times (or maybe the problem is small enough that is not visible)

I will give it a try with 100 ml and will see if that is the problem

 

[ste976]

 

[pentaxuser]

Yes what I saw is exactly what you have shown in #16. If this is a drum that is designed for 8x10 be that film or prints then my logic says that a 8 x10 negative is the closest to an 8x10 print and an 8x10 negative is the same size as an 8x10 print and b&w prints can even use developer that is more commonly used for negatives

If the print needs substantially more than 50 ml you'd think that Durst would give it a separate column which it doesn't. If lack of developer in terms of quantity is the cause of your problem you'd expect it to be there in every print and as far as I can see it is confined to the sky area only - at least in the prints you have shown us



pentaxuser

 

[koraks]

If lack of developer in terms of quantity is the cause of your problem you'd expect it to be there in every print and as far as I can see it is confined to the sky area only - at least in the prints you have shown us

We're looking at one little snippet from one print. Moreover, sky areas tend to be of uniform tone and slight variations show up more clearly in those areas even if they're present across the entire sheet. If you print an entire frame of rock formations like the little bits we see on the snippet as well, a problem like this will go entirely unnoticed.

 

[ste976]

Yes what I saw is exactly what you have shown in #16. If this is a drum that is designed for 8x10 be that film or prints then my logic says that a 8 x10 negative is the closest to an 8x10 print and an 8x10 negative is the same size as an 8x10 print and b&w prints can even use developer that is more commonly used for negatives

If the print needs substantially more than 50 ml you'd think that Durst would give it a separate column which it doesn't. If lack of developer in terms of quantity is the cause of your problem you'd expect it to be there in every print and as far as I can see it is confined to the sky area only - at least in the prints you have shown us



pentaxuser

Durst codrum should be just for prints, not negatives. So the way i read it is negative process stands for ra4

We're looking at one little snippet from one print. Moreover, sky areas tend to be of uniform tone and slight variations show up more clearly in those areas even if they're present across the entire sheet. If you print an entire frame of rock formations like the little bits we see on the snippet as well, a problem like this will go entirely unnoticed.

The stains are visible (and not so easily) on the skies, but you are right that they could be also be present in the other parts of the print but not be visible because of the texture

 

[ste976]

I can confirm that the problem was due to uneven development.
With 100ml with the durst drum the problem was still there. Had to use 200ml to get rid of the blotches.
I do remember a few years ago 100 ml was enough, maybe now i am using a thicker paper that does not rest as flat to the drum as it should and that is why need more liquid

 

[koraks]

So good that you figured it out!
Have you also tried reducing the temperature and developing longer? I'd expect this would also get rid of most of the unevenness.

 

[ste976]

I developed at 32C for 60 seconds. Did not go up to 100 seconds. I think at 100 seconds i would get too short exposure times.
I want to work with at least 10 seconds exposure time. I noticed that with short exposure times (3-4 seconds) i have problem to reproduce same density as test strip. Maybe the light intensity fluctuate a bit. To get to 10 seconds exposure time i am already at f/11 and using 2 stop density filter

 

[brbo]

I developed at 32C for 60 seconds.

60s might be a bit short for 32ºC. I use 55s at about 35ºC (I heat the developer to 38ºC, but I'm pretty sure temperature drops a few degrees when pouring in the developer even though I preheat the drum with warm prewash). RA-4 development is basically to completion, so 10s or so extra won't hurt. I think I read somewhere that Kodak's suggested time for 33ºC is 60s, so if you heat your developer to 32ºC and then temperature in the drum drops to something like 30ºC or less you might be seeing the effects of underdevelopment.

Did not go up to 100 seconds. I think at 100 seconds i would get too short exposure times.

There is no need to adjust exposure times to the development times. RA-4 does not work like BW film where you sometimes might expose film less and develop for longer or give more generous exposure and cut down on development.

 

[koraks]

I developed at 32C for 60 seconds. Did not go up to 100 seconds. I think at 100 seconds i would get too short exposure times.

No, RA4 is a develop to completion process for the most part. The difference in exposure will be marginal or even zero for a longer development time - especially if you also reduce processing temperature.
You can go below 32C just fine, too.

I noticed that with short exposure times (3-4 seconds) i have problem to reproduce same density as test strip.

Sounds like it's time to fix some more problems; a 3-4 second exposure time should be consistent enough not to produce visible variations even with a halogen/tungsten bulb and a basic timer. What kind of density variations are you getting? Can you post some examples?

 

[ste976]

I read on an old tetenal liflet that suggested develop time 60sec @32C with drum. But I will try longer. Actully at bellini told me to try 90/100 sec @32C. I'll try that.i thought longer dev needed less exposure time for same density