I've tried it in Tetenal minilab chemistry at room temperature. The result is mottled and black is not right.
I've located and bought Kodak RT/LU developer and the result at 25C (120 seconds) is the same - ugly mottle. I've tried developing for 180s - seems to look a bit better but still ugly.
Some old Supra III is fine in the same chemistry. Its somewhat fogged but no mottle.
I use vinegar stop and somewhat questionable bleach but it works fine with Supra III though.
Use a water rinse between your stop, which should be 2%, and the rest of your chems. BTW the Kodak RA/RT stuff works very well at 20-22C and keeps for a long time. I'm just finishing off the batches of dev and blix I mixed up in mid march and just did a test with some I mixed up two days ago, no visible differences.
Unless Supra III was a much better paper in terms of not being susceptible to "mottle" then it would seem that we are missing the real problem which I admit I have no idea about. It leaves the possibility that the newer Supra VC Endura is at fault or cannot be used at room temp. There has to be a difference here between Supra III and the newer paper surely?
From Kodak's FAQ "Can I use SUPRA ENDURA VC Digital Paper for optical printing?
Yes. When exposed optically the image will be high in contrast. If balanced on flesh tones, the neutrals will appear cyan."
Just might not be worth trying at room temp or with optical printing.
I've replaced the vinegar stop with a rinse and the results were the same.
I've replaced the questionable blix with separate and different bleach and fix. Results are the same.
Interesting thing is that I can hardly see the mottle before the bleach step. Perhaps its most pronounced at bottom layers of coating and silver image hides it?
From Kodak's FAQ "Can I use SUPRA ENDURA VC Digital Paper for optical printing?
Yes. When exposed optically the image will be high in contrast. If balanced on flesh tones, the neutrals will appear cyan."
Just might not be worth trying at room temp or with optical printing.
I'm well aware of that statement. However for the project I want to work on now the higher contrast is what I want and the skin color balance thing is a non issue.
If you can call Kodak, and give them the emulsion number on the package, you will find out the coating date. The coating may have been old or mishandled with excess heat.
I have been advised by a "source" that the current Endura requires more agitation than earlier versions and that you may see some mottle if agitation is marginal. This is sometimes seen in the "digital" versions of Endura.
When printing color I agitate for all or most time. A least some and probably most of few dozen test prints I did got as much agitation as can give them. None of them are mottle free. There is also a problem with Dmax even with prints developed for twice the normal time.
I contacted the dealer. He said that if I provide some samples both exposed and unexposed they can be sent back to the factory. He said that from his experience it would take at least a month.
Meanwhile I'm kind of stuck. The problem with Endura might or might not be inherent to the paper. At the moment I cannot afford the risk of buying another roll of it. From what I've read here there are problems with Fuji paper at room temp. It's really frustrating.