Scanning Negative Film- Noise/ Grain in blue skys

[mark.s]

I use an epson v700 and so far i really liked the results when scanning 4x5" neg film (pro160ns)
Today i scanned some images showing dark-blue skys (shot at a sunny midday)
The image came out quite good apart from the sky- compared to the rest of the image the blue sky shows a lot of big grain/ noise.
Has anyone here recogniced something similar with epson v700 and neg film?
How can i get rid of it?

(All my other shots taken in the morning or evening (low contrast) barely show any grain in blue skys.)

[Peter Gomena]

Check to make sure your scanning software has not reset itself to automatic sharpening. Check also that it is not in "scan draft" mode or that it is scanning in 8-bit as opposed to 16-bit mode.

[mark.s]

Thank you, but the settings are okay. (16 bit, no sharpening etc.)
Here are two 100% crops from a 2000 dpi scan, the darker/ more saturated the sky gets the worse gets the grain:

[dave_whatever]

I think colour neg film in general tends to get quite noisy in deep shadows/underexposed areas, hence why a lot of people expose them at a stop or two slower than box speed. I've certainly had very noisy shadows with BW400CN if I'm not careful.

[Peter Gomena]

Hmm. Not pretty. Well, if you're using Silverfast, you can turn on the Grain and Noise Reduction (GANE) feature and experiment with various settings. Try also scanning at a different resolution, say 2400dpi, or maybe even lowering it to 1600dpi, to see what happens. Altering the saturation of the blues in the selective color settings also may help. Sometimes you just have to play with it.

Depending on the scene, you can mask off everything but the sky and blur the blue layer or some similar manipulation in Photoshop.

If your final output is a print, try printing it to see how the printer renders the sky. It may not even show.

[Larry Gebhardt]

The scanner will pickup more noise in the denser areas of the film, so you would expect that the light sky would have more noise if it was the scanner (since it's negative film). Have you looked at the film with a loupe or low power microscope to see if the noise is really in the film? I would be surprised if it is, since I didn't think the V700 resolved that well, but it's possible.

[mark.s]

Unfortunately I don`t have a microscope or strong loupe to check the grain on the film sheet. But I think that its not grain but noise produced by the scan.
I already overexpose my neg. film a 2/3 of a stop to reduce "grain"...

Does your v700/750 produce less noise in dark blue skys?

[rdenney]

I get the same effect when I scan color images with a deep blue sky using a V750, no matter whether the film is negative or positive. For example, I had problems with posterization when scanning this 6x12 Velvia transparency:


Cannon and French Castle, Fort Niagara, 2009

I solved the problem for this image by scanning it in two parts in my Nikon scanner and then stitching. That is not a very satisfying solution for transferring to 4x5.

I bet I spent two hours trying to deal with the blue sky in this image, made on 4x5 Fuji 160C negative film:


Saltbox, 2012

I finally got something that's okay, but I still don't really like the color of the sky (the Velvia sky in the picture of the cannon is better). I ended up adding a touch of yellow (which has the effect of pulling out a bit of blue saturation and also muting it, the same as a painter will use an underwash of a complementary color to mute the final color), and reducing blue saturation. I have not figured out whether this is a Vuescan issue, an Epson issue, a Photoshop issue, or (as is most likely) a Rick issue.

I absolutely agree that it is not grain, but rather noise. The noise problem, though, is made worse by the minimal exposure received by the sensor when the light is having to punch through a thick negative. The blue sky is the worst of all worlds, in that it is very thick. The complement of the blue/cyan sky is orange, and that is stacked on top of the orange mask. I'm thinking the sensor on the Epson may be running out of gamut for reading that orange, and the blue channel (after reversal) is therefore clipped or so stuffed up into the top of its histogram that it posterizes.

It's a problem I would like to solve. I'm constantly struggling with blue skies when scanning negatives.

One thing I'm sure is going to be part of the solution: Make sure and don't overexpose (in the blue channel) blue skies. It would be kinda funny to use a thin blue filter with color negative film, but I'm not sure it would not help.

Rick "it's not grain" Denney

[mark.s]

thank you rick! exactly with this types of images i also have these issues...
adding a touch of yellow helps a bit to reduce the noise, also reducing black in the blues helps, but of course these methods also effect the look of the image- sometimes i like the blue sky to be dark and well saturated.
i will try different scanning softwares the next days.
maybe some "scanning expert" here can explain if it is a hardware or software issue?!

[Preston]

Mark,

I have run into this issue a time or two. Here's a tip that will help:

1. Open your un-adjusted inverted file in Photo Shop
2. Create a copy of the background layer
3. Go into Quick Mask mode
4. Use a soft brush at 100 % opacity and paint out everything except the sky
5. Exit Quick Mask Mode
6. Save the selection (you may need to use it later)

Now, you have an option. You can use either a Gaussian Blur, or the Noise filter in PS to reduce the noise in the sky. Either way, use a small radius.

7. Hide the marching ants (Ctrl+H)
8. Run the Gaussian Blur or Noise reduction filter.
9. Deselect your sky. (Ctrl+D)

This method will not affect your sky color, saving you a lot of time trying to get a good color balance there. Now, if you need to adjust the sky for color or brightness, you can load your sky selection from the Channels Palette and then create the needed adjustment layer. When you do this, the layer mask will be created automatically.

I am sure there are other ways to do this--there always is in Photo Shop, but this is quick and painless.

--P