View Full Version : Portra NC 8x10 processing problems

Stephen Vaughan
11-Nov-2005, 10:27
I recently had a large number of 8x10 Portra 160NC sheets processed at a commercial lab. Most of the sheets suffered from vertical streaking and uneven densities, particularly in areas of blue sky or grey mid tones. They also lacked contrast and the Kodak writing on the rebate appeared thin compared to previous negatives.

The lab doesn't seem to have diagnosed the reasons for the poor processing. However, as they have refunded and paid for the cost of re-shooting, I am obliged to get the new sheets developed there again. Obviously, I am very apprehensive and would welcome any advice or opinions on what is likely to be the cause and how the same problems are to be avoided.

Thanks in advance for your help......

John Berry ( Roadkill )
11-Nov-2005, 13:15
I would take an extra shot and have just one developed so that I could take the rest somewhere else if need be.

Stephen Vaughan
11-Nov-2005, 14:34
Thanks John - there are 90 sheets, so no opportunity for doubling up exposures - too expensive to do that with so many images and not possible to carry so much film/darkslides. I have used a box of film as test sheets, but the problem seems random and variable in its severity. Has anyone experienced similar problems and how have they been corrected? Thanks.....

Henry Ambrose
11-Nov-2005, 16:37
" I have used a box of film as test sheets, but the problem seems random and variable in its severity."

Now that is scary!

And it seems to mean that either you have bad film or bad processing. How about shooting one more test? Six sheets, all of the same carefully controlled scene, send three to your current lab and three to a lab you can absolutley trust. If you get a different result then I'd suggest you switch labs. Or work with your current lab until they fix it or give up.

I get a strange smudgy effect in smooth skies every once in a while with C41 films but I usually put it off to my film handling - like maybe I rubbed the film when loading or that its a characteristic of C41 sheet film. But its nothing like what you describe.

Frank Petronio
11-Nov-2005, 18:38
Try a new lab. Praus (http://www.4photolab.com) is good at mail order and large format C-41.