Unknow spots on developed C-41 film

[jonwo]

Greetings
I need help on identifying these unknown spots on C-41 developed film.

Kodak 160NC-2 ISO 160, shot at ISO 160
C-41 standard development at small commercial lab

These spots exhibit on a few other places on the same roll. This roll was loaded and shot just recently. I have seen similar spots on films developed by the same lab before but unable to identify what it is, what causes these.

I need a friendly suggestion on solid ground which I can feedback to the lab technician.

I plan to re-soak and rinse 6-frames again with pure water to see if it can remedy.

Thanks in advance.

 

[sevo]

This looks like scanner ICE artefacts - it is impossible to tell what the spots originally were before the scanner attempted to remove them.

 

[jonwo]

Good idea! Let me check with a reverse-lens loupe against a light source.

Add more detail about scanning process:
- ScanDual IV with VueScan driver but the original Konica Minolta software
- Auto Dust Brush turned on <aka ICE>
- Pixel Polish OFF
- Grain Dissolve ON ISO 100,@ 3/5
- this sample scanned at 3200dpi
- saved as TIFF
- magnified to 1:1 and output to JPG for this post

Any other idea?

 

[jonwo]

rescan with Auto Dust Brush turned off
it doesn't show the artifacts anymore.

it turns out those spots are sparkles of tiny light spots reflected off a glass wall or any extreme contrast spot (not necessary a glass or shinny object, e.g. light reflection off the dark color traffic light post)

I'm trying to rescan with a lower setting of dust removal. Unfortunately, there is only three setting to throttle (low--mid--high). The artifacts show up with mid and high setting.

I think this is independent of the VueScan driver, it is the Auto Dust Brush not 'intelligent' enough to differentiate.

 

[wpb]

is the Auto Dust Brush not 'intelligent' enough to differentiate

It is not. Unlike ICE that uses an infrared channel to map dust and scratches, the Minolta just guesses when it sees drastic, small, and well-defined changes in contrast. Best bet: clean negs as if they were going in a condenser enlarger, leave dust brush off.

 

[degruyl]

It is not. Unlike ICE that uses an infrared channel to map dust and scratches, the Minolta just guesses when it sees drastic, small, and well-defined changes in contrast. Best bet: clean negs as if they were going in a condenser enlarger, leave dust brush off.

Absolutely the best bet. You will probably have to spot the scans, but you probably would have had to anyway.

I generally turn ICE off (or don't turn it on, since I scan mostly B&W) and always turn software based dust and scratch removal off, and I have had good results. (different scanner, but the principal is the same).

For me, the problem with ICE is large negative tend to freeze the computer, or take hours to scan. It is very slow on my current system. Once I change, I might try it again. Remember, it can't put the actual image back, so it is no more valuable than spotting by hand.

 

[kzphoto]

Digital ICE on a BW neg is a no-no, isn't it? Never had good luck with it. However, this does look like Digital ICE artification -- Turn it off and it should go away.

 

[degruyl]

Digital ICE on a BW neg is a no-no, isn't it? Never had good luck with it. However, this does look like Digital ICE artification -- Turn it off and it should go away.

It does not work, but in many scanners it will try.

I think that the OP's negative is actually color, though. (Portra 160 NC, unless 160 NC-2 is different and I have never heard of it)

 

[jonwo]

It is a color negative. The pre-exposed edge reads NC160-2. Not sure how it is different from the original.
I find turning color negative to B&W gives me a lot of post-process capability in light-room development and printing. I do like to take color pictures too, depends on the how I like to express it.

Back to this scanning topics, it seems dust-removal process has a few varieties which is good. What is important is to understand such that we can master scanning and all that.

 

[Ronald M]

Just scan for for density and color and leave all the rest for photoshop.

Clean with a brush and "canned air'".