Dark Slides

[rimonk]

Being a new user to the film scanning world, I am having difficulty obtaining acceptable scans from darker slides.
Equipment used is a Plustek OpticFilm 8200i scanner with Silverfast Ai Studio v8.0.1r7 software.
With Silverfast I have tried the WorkflowPilot with the Task set to "Dark Photo" mode. This produces IMG_1.

IMG1 - Workflow.jpg (240.58 KiB) Viewed 8453 times

Next attempts using the more manual approach rather than the automatic WorkflowPilot produces results like IMG_2.

IMG2 - Manual Scan.jpg (234.81 KiB) Viewed 8453 times

What I really want is a result like IMG_3, which is a scan of an old print made from the same slide 45 years ago.

IMG3 - Original Print.jpg (242.36 KiB) Viewed 8453 times

It's almost as though the scanner is not emitting sufficient light although my more balanced slides have scanned OK.

Can anyone offer any advice or suggestions as to how I can achieve better results?

[LSI_Ketelhohn]

Dear rimonk,

First please make sure the red scan frame sits tightly around the image content.

Then you need to execute the image auto adjustment so the highlights and shadows are set correctly.

You can also adjust the brightness (Midtone) and contrast in the Gradation or picture settings dialog.

kind regards,
Arne ketelhohn.

[Andy614]

I have the same problem with dark slides (although I scan negatives), after the pre-scan I set the mid tone, shadows etc perfectly then I scan with 3600 dpi and the scan is dark.
this happens not every scan but approximately 1 in 5, if I re- scan with 2400 dpi the picture quality is much better, but I cannot blow it up be causes you can see square pixels.
If I then reset the shadows using photo shop the picture becomes grainy
would appreciate if somebody can help?

[KeithTalbot]

Hi

Exactly the same issue I just joined the forum to check for - scans of slides appearing much darker than they appear when eyeballing them against a light source.
Since the images posted by the person who started this thread demonstrate this perfectly I haven't posted any extra examples.
yes we can tweak the exposure and histogram, but this ends up looking like a compensation for a very under-exposed slide, and surely the point of the large colour depth is that we are not immediately losing half the dynamic range in exposure compensation ?

BTW - also aware that this might be a Plustek problem not a Silverfast problem (!!), but it would be nice if you could find a mismatch in some software range somewhere which meant this whole issue would go away with a software patch

Thanks in anticipation

[LSI_Ketelhohn]

Dear Keith,

The lamp brightness is controlled by the scanner itself.
SilverFast can not influence that.
SilverFast can only adjust the image information delivered by the scanner.

kind regards,
Arne Ketelhohn

[KeithTalbot]

Thanks for the fast reply.

I guess this is where spending the extra on AI Studio and IT8 targets comes in - do you have any feel for the typical variations from doing an IT8 calibration of the scanner compared with the default shipped profile ? How often does Lasersoft check the default profile against new shipments of Plustek scanners ? in case their calibration is shifting with manufacture ?

Also, my most recent scans of some 15 years old Fujichrome slides seemed were considerably improved by significant modification of the gradation curve / mid-tone brightness. Almost as though there is a major non-linearity in the Plustek sensor. Do you have any suggestion as to any objective measurements to take to go back to Plustek with ?

Thanks, Keith

[LSI_Ketelhohn]

We regularly test our offered scanners.
In case the production is altered we also get a new testing device.
So far we never had any significant variations.

Generally the the shipped profile is generated in a way that it will fit all production models.
This means the shipped profile tends to be smaller than the scanner's potential color space.
This means that the minimum and maximum values of the colors will always be met.
Of cause devices change over time and the way certain colors are seen might change.
So an image scanned again on the same device after a few years might look a little different.This might or might not be visible.
Also individual devices might show variations in color representation if compared.
This depends largely on the individual device.

Also as all optical devices scanners are subject to external influences.
Both temperature and humidity can influence how a device sees color values.

An individual IT8 calibration will measure the true range of colors for an individual device.
This enhances color stability and makes sure the scanner uses a controlled and defined color space.

When you contact Plustek I would assume a few sample scans should be enough to show your issue.


kind regards,
Arne Ketelhohn

[doctor-a]

I have the same problem and I believe I understand its nature. I see the same thing with colour negatives.

It has nothing to do with colour calibration. I've used the IT8 calibration slide and it makes no difference.

The problem occurs only when scanning at 3600 or 7200 dpi and only in certain cases. The issue is not SilverFast as such, it is the scanner hardware - the lamp, as many have guessed here.

As Arne has pointed out, in the first instance make sure the red scan frame sits tightly around the image content, you may have to give it some extra room.

I have a slight suspicion that the highlights at the top of your image are also contributing to the problem. It is as if the scanner is calibrating the the lamp luminosity based on that region. I haven't yet tried this but try changing the orientation of your slides/negatives so that the highlights are in a different region.

I recently bought this scanner, if I cannot resolve this problem I may return it as faulty.

[Andy614]

I can confirm that the red frame needs to tight around the image, otherwise the bright edges have an impact on the overall brightness, however this may not be the reason for the dark slides.

Take notice of the noise of the scanner when scanning 3600 or 7200 dpi if it starts quietly the scan will be dark and take 5 minutes with 3600 and 15 mins with 7200dpi and if it starts loudly the scan will always take about 1 minute.

sometimes the scan starts load and fast but then the infra red scan runs slowly in this case the ISRD will not work, the image will be scratched and grainy.

I sent my scanner back to Plustek but it came back with the same problem as when I sent it

It seems that Plustek believes that Lasersoft have a software issue! that is only with MAC OS (they do all their testing with windows) and cannot reproduce the problem

Lasersoft believe that Plustek has a problem because software cannot effect the speed of the hardware etc.

I do not know which of them are correct, probably both wrong!

Unfortunatly I do not have a windows machine that I could change to and would appreciate Plustek and Lasersoft getting into a dialogue

When the scanner works the combination software and hardware is brilliant

please please do something to save your reputations

[LSI_Ketelhohn]

Dear customer,

We are already in contact with Plustek about this issue.
They are currently analyzing their driver.

kind regards,
Arne Ketelhohn.

[Fgcm]

I have a similar problem.
Plustek 7400

BW negatives: dark areas on the negative (which are white on print) are badly scanned.

Slides: are too dark. Well exposed slides seem underexposed by 2 / 3 stops.

Please, we all need a fix for this problem

Regards
Franco

[Fgcm]

Using multi exposure, second scan looks ok in the small preview in the lower left corner of the screen.
If we could increase the exposure in any way, the scan would be great.
Regards
Franco

[LSI_Ketelhohn]

Dear customer,

most devices unfortunately do not allow to adjust exposure.

But to make sure this done right.
Please remember that it is essential that the red scanframe is placed tightly around the image.
Unexposed material inside the frame will disturb highlight/shadow detection.

Also please check the output histogram if the Highlights and shadows are placed correctly there.

kind regards,
Arne Ketelhohn.

[Fgcm]

Thanks, I checked the frame. It's well placed.
I suspect that plustek choose a "safe" exposure setting, thinking to the perfect reproduction of color negatives.
It's good choice for most films.

When scanning very dense and contrasty BW negatives and dark slides like Velvia 50, a higher exposure would be perfect.
I understand this is a problem of the manufacturer and not of Silverfast.

I try to find an unorthodox solution.

Thanks
Franco

[kat634]

I wish I'd found this discussion before buying a Plustek scanner! I am having the same problem with intermittent dark scans with a brand new 8200ai. I contacted Plustek, who sent me a replacement Frameworks folder (oddly, it may have contained an older version than the one that was installed by their included software disk), which did not solve the problem. I just reported this result to them. I can get maybe three negatives scanned acceptably before getting an unusably dark scan. Today I tried shutting off the scanner after the first dark scan, in case it was overheating (a possibility suggested by Lasersoft support). I then got one acceptable scan before it reverted to producing dark scans.

What are we to do if and when Plustek is the only new high-resolution film scanner option available? I'd prefer to keep my 10-year-old Polaroid scanner going forever, but eventually it will fail. And there haven't been software updates for it since v6 of ai Studio.