Dust removal alters or removes image details

[Pál_K]

I've been using an Epson V800 with Epson Scan for about five years. Whether I'm selecting Dust Removal with B&W negatives or Digital ICE with color negatives, I see the same problem: distortion or actual elimination of objects in the image. The actual dust removal is only fair - I'm surprised at what it misses.

For B&W, I've seen distant (i.e. small) objects, actual image objects, turned into little trapezoids; with color I've seen a cluster of distant trees removed entirely.

I can't trust the dust removal features any more, even though I've not chosen an aggressive setting. So, now I'm just de-spotting by hand - though that is very time consuming.

Is this image object alteration or object removal normal and just accepted? An I doing something wrong?

 

[Mcary]

Things may have changed with more recent versions but its always been my understanding that Digital ICE doesn't work on B&W images, something to with the IR Sensor that is used to ID the spots/dust for removal. I'm using VueScan with my Epson V700 and find that the Digital ICE does a pretty good job with C41 color film. As far a B&W negative that's pretty left to a Rocket Blower and the spot removal tools in PS.

 

[Pál_K]

Things may have changed with more recent versions but its always been my understanding that Digital ICE doesn't work on B&W images, something to with the IR Sensor that is used to ID the spots/dust for removal. I'm using VueScan with my Epson V700 and find that the Digital ICE does a pretty good job with C41 color film. As far a B&W negative that's pretty left to a Rocket Blower and the spot removal tools in PS.

Right - I use Digital ICE with color. What it did was remove a group of trees on a distant riverbank.

For B&W I select just ordinary dust removal. It removes some of the dust, but alters the shape of actual objects which I suppose it thinks is dust.

 

[armadsen]

Things may have changed with more recent versions but its always been my understanding that Digital ICE doesn't work on B&W images, something to with the IR Sensor that is used to ID the spots/dust for removal. I'm using VueScan with my Epson V700 and find that the Digital ICE does a pretty good job with C41 color film. As far a B&W negative that's pretty left to a Rocket Blower and the spot removal tools in PS.

It’s because color negative film has no silver left in it, and the color dyes are transparent to IR, but dust is not. So IR is used to image only the dust, then that can be used by the computer to “patch” the spots where the dust appeared. It still doesn’t know what actually was covered by the dust, so it has to make something up and isn’t always perfect.

On the other hand, standard B&W film’s silver grains are just as opaque to IR as they are visible light, so there’s no way to use IR to see just the dust. Instead, the computer uses an algorithm to try to identify dust purely by analyzing the scanned (visible light) image itself. Again, it’s not perfect and can mistake things that are not dust for dust.

I do my best to physically remove dust before scanning with a carbon fiber brush and air blower, then manually spot heal to get rid of what gets through anyway.

 

[Chriscrawfordphoto]

I've never seen Digital ICE remove objects like that. My Nikon scanners have it and I use it on color negs and slides. What I have noticed is that you can set it for different levels of correction. The low setting gets rid of most dust without causing loss of image quality, but the medium and high settings (especially the high setting) reduce fine detail resolution so they're only used if I have a badly damaged, scratched up neg (and I take good care of my film so that's rarely needed). Even then, the medium and high settings have never removed whole objects; they just made the image soft.

The non-ICE dust removal that you're using is purely software based. ICE uses infrared light and a special sensor to detect dist and scratches to remove, and it works well because it only removes real dust. The software-based system has no way to determine if a spot is real dust or an actual detail in the image, and it often makes the wrong decision.

 

[das]

One of the reasons I switched to XP2 for b&w film is because of digital ICE can clean up scratches and dust. I can't tell you how much time I spent manually trying to remove dust from scans of normal b&w film. And XP2 has incredible latitude for fixing in post, although it can get a little grainy if you try to brighten up the mid-tones and whites too much.

 

[Godfrey]

I've been using an Epson V800 with Epson Scan for about five years. Whether I'm selecting Dust Removal with B&W negatives or Digital ICE with color negatives, I see the same problem: distortion or actual elimination of objects in the image. The actual dust removal is only fair - I'm surprised at what it misses.

For B&W, I've seen distant (i.e. small) objects, actual image objects, turned into little trapezoids; with color I've seen a cluster of distant trees removed entirely.

I can't trust the dust removal features any more, even though I've not chosen an aggressive setting. So, now I'm just de-spotting by hand - though that is very time consuming.

Is this image object alteration or object removal normal and just accepted? An I doing something wrong?

heh. I've never used dust removal algorithms because I've never trusted them to do the right thing. I do my best never to let my negatives get dusty in the first place ... best dust removal you can have ... and then spot by hand, manually. This was a pain in the darkroom era, but is so easy with digital image processing tools I just don't seen why I shouldn't.

G

 

[Bill Blackwell]

I've been using an Epson V800 with Epson Scan for about five years. Whether I'm selecting Dust Removal with B&W negatives or Digital ICE with color negatives, I see the same problem: distortion or actual elimination of objects in the image. The actual dust removal is only fair - I'm surprised at what it misses.

For B&W, I've seen distant (i.e. small) objects, actual image objects, turned into little trapezoids; with color I've seen a cluster of distant trees removed entirely.

I can't trust the dust removal features any more, even though I've not chosen an aggressive setting. So, now I'm just de-spotting by hand - though that is very time consuming.

Is this image object alteration or object removal normal and just accepted? An I doing something wrong?

I know exactly what you're talking about. I've found that even at mild settings certain items in the frame are sometimes removed or altered - and the dust remains. Even faces are affected. There's no intelligence at work here (artificial or otherwise).

Bottom line: Don't use aggressive settings and/or remove unwanted dust and other artifacts by hand.


Kodachrome 64 scanned via plustek 8200i - mild anti-dust setting used, but most artifacts were removed by hand.

 

[Bill Blackwell]

Here's another I just scanned this week. All dust and artifacts were removed by hand.

Tri-X - plustek 8200i film scanner

 

[das]

I always had dust that seemed to be in emulsion (and not on the surface of the negative) that could not be removed by external methods. Maybe sloppy developing or something else. I am just glad not to have to deal with it any more.