Vuescan black and white TIFF files - Grey vs. RGB

[SvendN]

Hello all,

I am hoping to get some help with Vuescan settings for scans of monochrome negatives. Specifically, when I set Vuescan input and output (TIFF file type) to 16 Bit Gray, the resulting scans look completely washed out in PSP X8. As if the negatives were badly underexposed, in other words. There is no detail at all in the highlights. However, in the Vuescan preview pane and Windows Photo Viewer, the images look completely normal.

PSP will render scans of the same negs normally if I set Vuescan to input and TIFF output as 48 Bit RGB (all other settings unchanged). But the file size is 3 times larger, which is a drawback I am trying to avoid as the scans are of 6x6 and 6x9 medium format negatives, resulting in 150 to 230 MB files, respectively, if 48 Bit RGB is used.

Can anyone suggest a cause and solution to this? Is there a setting in PSP that will allow the 16 Bit Gray scans to import and render normally? FYI, I have tried disabling Colour Management (from reading another thread here re. import problems, albeit in colour) but with no effect.

BTW, PSP is updated to latest service pack.

Any help greatly appreciated!

Many thanks in advance,
Svend

[JoeB]

I don't actually have the answer to your question except to say that scanning B&W negatives often results in a more washed out result which can be adjusted using curves, etc., in your image editor. However, if you're getting a good result with a 48 bit setting then the image info is obviously there, although I'm surprised then that you wouldn't get sufficient detail with 16 bit output also. Have you tried using the native scanner software that comes with your scanner rather than Vuescan? If so, what is the result? Also, for those who do this with Vuescan it might help if you posted a screenshot of the settings you are using. And are all the settings the same whether you are selecting 16 bit or 48 bit?

[SvendN]

Hi Joe,

Thanks for the reply. To answer your last question first -- yes, all settings are the same, except selecting 16 Bit Gray or 48 Bit RGB. Rather than post screenshots of every tab in Vuescan, here are my basic settings:

Input tab:
2400 dpi
B&W neg
16 Bit Gray or 48 Bit RGB input
Multi-exposure off

Filter tab:
Sharpening off
Grain reduction off

Colour tab:
(Note: these settings are left as generic as possible to avoid Vuescan applying its own curves to the scans - I want a straight, flat scan)
Colour balance = none
Black and white points = NA (disabled if Colour Balance = none)
Curve low = 0.001, Curve high = 0.001 (set as low as possible to avoid clipping)
Brightness = 1.0 (varies depending on shadow detail I want to retain)
Film Generic/Colour/Negative
Output colour space = Gray

Output tab:
Tiff profile on
Tiff file type = 16 Bit Gray or 48 Bit RGB
RAW off
DNG off
Tiff compression off

As far as I know, the above are the most relevant to the question, but if I have left something out that matters, please let me know and I can repost.

You mention that scanning leaves flat images, and I am aware of that. In fact, that is my goal to achieve a flat image that retains as much highlight and shadow detail from the neg as possible. All curve adjustments, etc., are left to Aftershot and PSP. But this situation is entirely different -- the 16 Bit Gray images are rendered very washed out, as if the negatives were overexposed in the camera by 3 or 4 stops, yielding an underexposed print. This is odd because, as I noted, in Windows Photo Viewer and Vuescan preview they look fine.

FWIW, it seems that leaving one or the other (either input or output) at 16 Bit Gray, and changing the other to 48 Bit RGB, gives the same outcome. In other words, they both have to be at 48 Bit in order to render normally -- if one is at 16 Bit then it doesn't work.

Further, the 16 Bit Gray images don't show up at all in Aftershot, whereas the 48 Bit RGB import normally (not sure if that is relevant or not).

Finally, I have not tried this with the native scanner software. Might be worth a try, but I have never bothered to use it so it would be another thing to learn.

Any further thoughts most welcome. I am hoping there is a simple setting in PSP that I am overlooking which would sort this out.

Thanks,
Svend

[Jean-Luc]

PSP will render scans of the same negs normally if I set Vuescan to input and TIFF output as 48 Bit RGB (all other settings unchanged). But the file size is 3 times larger, which is a drawback I am trying to avoid as the scans are of 6x6 and 6x9 medium format negatives, resulting in 150 to 230 MB files, respectively, if 48 Bit RGB is used.

Hi SvendN,
if you have no success to obtain a well balanced scan, I suggest you scan at 48 Bit and reduce to 16 Bit in PSP which will give, in final, an acceptable size ... A script could do the task...
Best regards,
Jean-Luc

[SvendN]

Hi Jean-Luc,

I am able to obtain a well balanced scan in 16 bit, as evidenced by their normal appearance in Vuescan and Windows. But they just won't render normally in PSP or Aftershot for some reason. If I can find a fix without having to convert a 48 bit, that would be preferred. If you have amy other suggestions then I'd welcome hearing back.

Regards,
Svend

[JoeB]

Hi Jean-Luc,

I am able to obtain a well balanced scan in 16 bit, as evidenced by their normal appearance in Vuescan and Windows. But they just won't render normally in PSP or Aftershot for some reason. If I can find a fix without having to convert a 48 bit, that would be preferred. If you have amy other suggestions then I'd welcome hearing back.

Regards,
Svend

What do you mean by saying that you get a normal appearance in Vuescan and Windows? In Vuescan you're just seeing Vuescan's preview, which is not necessarily going to be what is being output. But what do you mean by viewing it in Windows? Windows is an OS, not a graphic editor or graphic viewer. Do you have any graphic programs other than PSP or Aftershot that you can use to open those 16 bit images into so that you can see how they render them?

[SvendN]

Hi Joe,

I meant WIndows Picture Viewer. I think I mentioned that in a couple of earlier posts.

As for other graphics programs, other than PSP and ASP I only have Picasa. The 16 bit files show normally in that program also (good idea to check, though - thanks). I would insert a screen shot here but I can't seem to be able to paste into this message(?) -- clicking on the "Img" icon only asks for a URL. I would also like to be able to insert a screen shot from PSP so I can show you what I mean.

Thanks,
Svend


Edit: I just figured out how to add images here -- sorry, I'm new to this forum. See attachments...

Paintshop screenshot 48 bit (left) w. 16 bit (right)

Picasa screenshot 16 bit

[Jean-Luc]

Hi Jean-Luc,

I am able to obtain a well balanced scan in 16 bit, as evidenced by their normal appearance in Vuescan and Windows. But they just won't render normally in PSP or Aftershot for some reason. If I can find a fix without having to convert a 48 bit, that would be preferred. If you have amy other suggestions then I'd welcome hearing back.

Regards,
Svend

Hi SvendN,
did you try to convert a well balanced 48 bit image to a 16 bit image in PSP ? I mean, does the result display correctly or not (convert, save, close, open again the 16 bit for comparison) ?
If the 16 bit converted image displays the same as the 48 bit, it could be some difference in the original TIFF file generated by Vuescan which PSP is not able to read.
Could you also put somewhere some files so we can test them on our systems?
Best regards,
Jean-Luc

[SvendN]

Hi Jean-Luc,

I did as suggested and converted a 48 bit scan to Greyscale (there was no option for 16 bit conversion; only 8 bit Greyscale); then closed PSP; cleared temp folder; reopened PSP. The Greyscale image looks fine -- no problems.

I don't think it will be possible to share one of these scans, as they are minimum 50MB, being from 6x6 cm medium format negs. at 2400 dpi.

At this point I will take your suggestion and convert the 48 bit scans to Greyscale, as it cuts the file size by two-thirds and should still allow full editing. I will try a copy of a test image to see how the quality comes out.

Thanks very much for your time in trying to help out here. Much appreciated.

Regards,
Svend

[SvendN]

Since yesterday I have tried a couple of other things in an attempt to fix this, but to no avail. Setting the first five "Convert Image" preferences in PSP to "Do Nothing" had no effect (Preferences>General Program>Auto Action).

Then I tried unchecking TIFF Profile in Vuescan, and setting Output Colour Space to sRGB instead of Gray, but no change.

Then I created a very dark scan by lowering the brightness in Vuescan (by more than 0.5 on the scale, which is quite a lot), and lo-and-behold this worked. Go figure! The resulting scan looked more or less normal in PSP. The final scanner exposure was not ideally where I would want it, but at least it's useable.

BTW, I forgot to mention: PSP wants to edit the resulting 16 bit scans using Camera Raw rather than it's native Edit tab controls. Strange. Opening the files in the Manage and Adjust tabs works fine, but at the Edit tab it launches Camera Raw. It does not do this with the 48 bit scans. Aftershot does not even recognize the 16 bit scans at all, which is equally odd as it is a Raw editor. Not sure if that is a clue for anyone, but there it is.

So I am left with a couple of work-arounds: (1) do as Jean-Luc suggested and scan in 48 bit, keep that as the master scan file, save a copy and downsize that to Greyscale; or (2) make very dark scans in 16 bit and try to work with those. The latter option is least preferred, as trying to nail the scanner's exposure from a very dark preview is pretty hit and miss. I like to tweak the brightness in Vuescan so I can maintain a sense of light in the resulting image, and keep shadows and highlights in balance. So trying to guess at that from a dark preview is not going to work.

At this point, unless anyone else has a solution, I will do scans in 48 bit and downsize those. Not an ideal fix, as I would prefer a proper tweak to either Vuescan or PSP and just be able to scan in the manner I want without creating massive files. I am really puzzled as to why this is happening. It seems like such a basic task, to create a simple 16 bit grey scan and bring it into ASP or PSP and go to work.

Thanks, and regards,
Svend

[JoeB]

Then I created a very dark scan by lowering the brightness in Vuescan (by more than 0.5 on the scale, which is quite a lot), and lo-and-behold this worked. Go figure! The resulting scan looked more or less normal in PSP. The final scanner exposure was not ideally where I would want it, but at least it's useable.

When you use this method to create a scan that looks OK in PSP, what does that image look like in Windows viewer and Picassa?

[SvendN]

Hi Joe,

They are very dark, and show in Picasa exactly as in the Vuescan preview. I've attached the Picasa screenshot below. The top row left and middle are the original 48 bit scans, which look good in all programs; the bottom-middle is a 16 bit dark scan converted in PSP (with a few curve adjustments added), which now looks good in all; but the other three (the dark ones) are untouched 16 bit scans as they came directly out of Vuescan. These are the ones that look "normal" now in PSP. (And aren't recognized at all in ASP). Weird, eh?

Any ideas? Still scratching my head about this one...

Svend

[JoeB]

I'm afraid that you've covered all the bases and I don't have any new suggestions as to the issue. I lean toward Jean-Luc's thought that there is some image information embedded by Vuescan in those 16 bit scans that don't affect rendering in other programs but that is being interpreted (or misinterpreted) by PSP that is causing the issue.

[SvendN]

Joe, would it be worth contacting Corel support about this? Or do you think this is a Vuescan issue?

BTW, since my last post I have rescanned the same image as 24 bit RGB, and PSP renders it normally -- exactly as it came out of Vuescan preview. File size is only 50% larger than 16 bit :-/ but is still much smaller than the 3x larger files of 48 bit. Interestingly, Camera Raw does not kick in in PSP at 24 bit, and I am able to open this file in Aftershot, so all is well there. I will try working with one of those to see how the image quality turned out, and go from there. Unless there is another fix to allow me to use 16 bit, sticking with 24 bit may be where I end up with this.

Thanks for all your input. Appreciate it.

Svend

[JoeB]

While I have Vuescan I don't have a b&w negative to test with. It's hard to say if it's a Vuescan issue or PSP issue without, first, someone testing it on their systems with PSP to see if they get the same results that you do. If it works properly for others then I would go with it being your Vuescan driver. If they get the same result as you do then perhaps PSP shouldn't be misinterpreting the image info embedded by Vuescan when scanning 16 bit. Even then, I'm not sure Corel would find it cost effective to troubleshoot the matter if it only happens with one type of scanning software. That's one reason I was asking if you had tried the same thing with the native scanning software that comes with your scanner. Which reminds me to ask, do you have the latest Vuescan driver version?