For several years in our school darkroon we have been running a CP-31 processor with Kodak RA-4 RT Developer. The processor was out for repair much of last year and was recently put back into service. Coincidentally, students have switched to using Portra NC films and the new Portra Endura paper. My experience previously was running films such as VHC, VPS, Kodak Gold 100, Fujicolor, Agfa Ultra, etc., and the older Portra, Supra, Ultra papers. So, several things have changed recently, and the print quality has been affected.
The Portra NC film seems very low contrast and from what I can see in the prints, I don't like the color rendition at all. But, the problem could be the processor timing or replenishment, new paper, etc., so I'm hoping someone can give me a clue as to the cause of the following problem. The prints seem to be for example, both cyan and magenta/red at the same time. Minor filter pack changes seem to make bigger changes than with previously used materials. But the color seems just awful to me and I can't figure out the cause.
I'm not getting blue-blacks and have adjusted the processor speed to give a 45 second development time (i.e., 280mm/minute per the manual). So, I don't think it is underdevelopment. The processor has a replenisher unit and I haven't changed the rate settings. I have also slowed the processor to give more development but that hasn't improved things. The prints don't have that cyan stain that occurs with blix contamination. Nor do they appear low contrast and gray because of improper blixing.
But, skin looks jaundiced at the same time that it seems magenta or blue in other areas. Likewise, pavement looks magenta in one area and cyan in another and reflections don't seem to be the cause of these variations. It is like the colors have crossed-over, but in areas of similar tone rather than a shadow-highlight cross-over.
No one is (correctly) using the same combination of materials/technique so I can't point to any sort of consistency in that regard. (Some may be using similar materials but their technique otherwise varies in regard to over-/underexposure quality of the roll, or subject matter, or lighting conditions or film speeds 160/400.)
Unless I'm missing something obvious, what I think may be happening is the local lab where students get their film developed is experienceing a downturn in the demand for film processing, chemicals may not be turning over as rapidly as in the past, and the QC may also not be what it was in the past. A couple local photographers that use this lab have indicated they have recently had problems with film developed at this lab. But, I can't say that has been my experience and perhaps the lab is really OK. I've never had a problem with them, but it has been several years since I've used their services.
Could poor film processing cause the type of problems we are experiencing or does something else come to mind? Maybe this is a local thing. Have others experienced similar results?
What would we expect to see in terms of a color shift if the paper was being overdeveloped?
This situation sort of reminds me of the dislike I had for the old Ektar 25. That film always seemed to have a magenta bias to me and I disliked it tremendously. But, at least I could point to the color bias and say it was magenta. I can't really do that with the Portra film I'm seeing now. It seems very low contrast but not consistently off in one direction colorwise.
I need a clue. Thanks in advance for any insights.
joe
The Portra NC film seems very low contrast and from what I can see in the prints, I don't like the color rendition at all. But, the problem could be the processor timing or replenishment, new paper, etc., so I'm hoping someone can give me a clue as to the cause of the following problem. The prints seem to be for example, both cyan and magenta/red at the same time. Minor filter pack changes seem to make bigger changes than with previously used materials. But the color seems just awful to me and I can't figure out the cause.
I'm not getting blue-blacks and have adjusted the processor speed to give a 45 second development time (i.e., 280mm/minute per the manual). So, I don't think it is underdevelopment. The processor has a replenisher unit and I haven't changed the rate settings. I have also slowed the processor to give more development but that hasn't improved things. The prints don't have that cyan stain that occurs with blix contamination. Nor do they appear low contrast and gray because of improper blixing.
But, skin looks jaundiced at the same time that it seems magenta or blue in other areas. Likewise, pavement looks magenta in one area and cyan in another and reflections don't seem to be the cause of these variations. It is like the colors have crossed-over, but in areas of similar tone rather than a shadow-highlight cross-over.
No one is (correctly) using the same combination of materials/technique so I can't point to any sort of consistency in that regard. (Some may be using similar materials but their technique otherwise varies in regard to over-/underexposure quality of the roll, or subject matter, or lighting conditions or film speeds 160/400.)
Unless I'm missing something obvious, what I think may be happening is the local lab where students get their film developed is experienceing a downturn in the demand for film processing, chemicals may not be turning over as rapidly as in the past, and the QC may also not be what it was in the past. A couple local photographers that use this lab have indicated they have recently had problems with film developed at this lab. But, I can't say that has been my experience and perhaps the lab is really OK. I've never had a problem with them, but it has been several years since I've used their services.
Could poor film processing cause the type of problems we are experiencing or does something else come to mind? Maybe this is a local thing. Have others experienced similar results?
What would we expect to see in terms of a color shift if the paper was being overdeveloped?
This situation sort of reminds me of the dislike I had for the old Ektar 25. That film always seemed to have a magenta bias to me and I disliked it tremendously. But, at least I could point to the color bias and say it was magenta. I can't really do that with the Portra film I'm seeing now. It seems very low contrast but not consistently off in one direction colorwise.
I need a clue. Thanks in advance for any insights.
joe
I usually develop normally. What I have found is that the paper is rather self limiting in that it goes to its desired contrast and speed and then pretty much stops with a slight red-cyan shift if anything. The cyan is on top, and so any over agitation tends to overdo the cyan just as overdevelopment will increase cyan, then magenta. Usually though it is just a slight density increase.