Excessive Grain in Scans

[bsantana]

I am attempting to learn the features of Ai 6.0 using my SS4000 (not plus) and I like the interface. I am having a serious problem with grain in both transparencies and negatives that I don't experience using Polacolor Insight5 that also came with the scanner. I started not using GANE, then tried GANE and it did provide some improvement. I'm not sure I understand the workflow after reviewing the documentation. Is it normal to have considerable pixelation and noise when scanning without GANE?
Thanks.
Barry Santana

[ianders1]

Barry,

Check to see if Auto-Sharpen is checked. I think that it is on by default and this would definitely add some serious noise/grain depending on how much it sharpened.

[bsantana]

The first thing I noticed was that autosharpen was on. I next tried less sharpen, then turned it off altogether. Not much difference - still considerable grain or noise. It almost looks like popcorn artifacts. I get a nice smooth scan with the same slide, same scanner using Polacolor Insight. GANE takes most of it out, but it's not as smooth as using PCI and I fear that details are softened using GANE. I would like to know if I am using the correct procedure for GANE. Thanks.

Barry

[LSI_Belli]

Sharpening and/or removing noise

It is true that sharpening an image might also increase the noise. The following entry in the forum explains for example how to sharpen an image without increasing the noise in dark areas:

viewtopic.php?t=1650

GANE enables to remove image noise while preserving the images. If there is not much noise, the parameters can be set as follow: an intensity of 50 and a threshold around 5-15 are OK.

The workflow is simple: make all your adjustments (e.g. color correction) and then choose the filter you want to apply (e.g. GANE).

However, it not possible with the actual SF version to "denoise" the image with GANE and then sharpen the image. This feature will be available very soon

Thomas

[ilyons]

Unless you are scanning high speed film with slides (positives) you should not need to use GANE. If the image is grainy check that you have the scan resolution set to a value such as 4000ppi (the Polaroid default), Q-factor at 1.

[bsantana]

Thanks for the 2 comments. Ian, my first test was on a Velvia transparency and I was using 4000 dpi. I had the Q factor at 1.5, the recommended & default value. The second test was on APS Advantix 200 negative film. It was also grainy. There was grain in all colors. The blue sky was the worst, but yellow, brown and green were also pretty bad. The colors and tonal quality was *much* better than Polacolor software on the Advantix film.

I will try LSI's suggestions and follow the workflow precisely. I am afraid that I have a setting(s) incorrect as I don't have this problem with Polacolor. I will see if one of your tutorials provides some help with this.

[Gregory C]

a couple of comments.

1. if you set the dpi manually, you don't need to set the Q (quality) factor. the Q Factor was designed to be used by people scanning for a specific printed output purpose where the size and line density of the printed output was known. if you are scanning for archival purposes or for on-screen viewing, the Q Factor can and should be ignored. just set the dpi.

2. related to #1, if you want to scan at the highest resolution that your scanner can provide, and you are scanning for archival purposes, use the resolution slider to select a resolution. other than the absolute highest resolution at the right end of the slider, all of these values are hardware resolutions. the highest one is an interpolated resolution (which in my opinion should not be accessible from the slider). for example, my Nikon scanner supports 4000dpi. the slider includes all hardware resolutions up to 4000 and then an interpolated resolution at 8000dpi.

3. I have scanned quite a few rolls of APS film using the Nikon APS adapter. even at 4000 dpi, scans of APS 200 can be quite grainy. in many cases, this is due to the low quality of the film itself. when available light is not ideal, the film gets grainy *very* quickly. the new (and excellent) GANE feature can help to reduce this grain quite effectively but I would use it only on frames that are darker and therefore grainier. in the future, try to use APS 100 film if you can find it. the grain should not be as pronounced.

4. I don't know how the Polaroid APS adapter works. with the Nikon adapter, the APS film gets tighter every time it is loaded and scanned. after being loaded 3 times, the film is usually too tight to load into the adapter again. my adapter has been sent in for repairs at least three times due to this problem (and the fact that the Nikon adapter uses plastic cogs/wheels which strip easily, reportedly to protect the film). to guard against this, I have begun to scan and archive all of my APS film in HDR 48 Bit Colour format. this means that I only have to scan the film once. with the HDR format, I can 're-scan' the film anytime by loading the HDR images into SilverFast HDR (now with VLT although I suspect that VLT doesn't invert negative HDR thumbnails; yet).

[bsantana]

Gregory,
Thanks for your comments. Its uncommon to hear from anyone who has scanned APS film. I normally use Fuji (I still have many rolls of the old 100 film), but have been experimenting with differnt types of film to find something that compares to Provia F in APS. I have not been happy with the old Fuji ASA 100 film and am definitely not happy with the Kodak Advantix 200. I am having similar grain problems with my 35mm Velvia slides scanned using SF Ai6.0, so I think that I have other problems that I need to solve. I do appreciate your comments on the APS film and particularly the mechanical problems. Thanks.