Scanning Slides

[Steven Ruttenberg]

I am finding that a slide that is underexposed, while it looks fine on the light table, is a pita to scan and then adjust. Seems you lose the crispness of the focus during the scan due to it being underexposed, plus it is hard to bring it up in ps or other software. Wonder if this is just a limitation of the scanner (V850 and calibrated for focus) using Vuescan, creating a raw file so that I can eventually run it thru colorperfect and also for archiving.

Looks like the Fuji Provia 100F needs like 2 or 3 stops over what is metered for a strongly backlit or dim scene. Is there any advice on this?

[Ted Baker]

Try doing separate scans at different exposures. low res is fine and quick

1. Do the first scan raw scan with automatic exposure.
2. Do a second scan where you adjust the exposure gain to blow out the highlights, this will destroy them

Work on the two scans separately, see if you can get a pleasing result for each "half" of the tonal scale. Then investigate multiple exposure.

Remember that neither the monitor nor a print is capable of the contrast ratio of backlit or projected transparency so a tone curve with some compression somewhere will be required to "recreate" what you see on the slide.

Contrast definitely has an effect on our perception of sharpness, the un-sharp mask works on this very principal.

Hope that helps. Hopefully you will get some more useful tips from slide shooters.

[Alan Klein]

You can't get blood from a turnip.

[Steven Ruttenberg]

Try doing separate scans at different exposures. low res is fine and quick

1. Do the first scan raw scan with automatic exposure.
2. Do a second scan where you adjust the exposure gain to blow out the highlights, this will destroy them

Work on the two scans separately, see if you can get a pleasing result for each "half" of the tonal scale. Then investigate multiple exposure.

Remember that neither the monitor nor a print is capable of the contrast ratio of backlit or projected transparency so a tone curve with some compression somewhere will be required to "recreate" what you see on the slide.

Contrast definitely has an effect on our perception of sharpness, the un-sharp mask works on this very principal.

Hope that helps. Hopefully you will get some more useful tips from slide shooters.

I will try what you suggest. I already tried multiple exposure with not much success even with setting gamma to 2.2 in photoshop. Will let know results.

[Steven Ruttenberg]

You can't get blood from a turnip.

Or a vampire

[Ted Baker]

I will try what you suggest. I already tried multiple exposure with not much success even with setting gamma to 2.2 in photoshop. Will let know results.

One aspect of what I trying to convey, is reduce the problem to small chunks. I am only guessing what your problem is because I can't see any example.

The other thing to consider is why are you using a raw scan for color transparency? Is it so you can use colorperfect? Otherwise I can't see what you hope to gain, and believe you may just be causing yourself some unnecessary confusion, and problems...

[Steven Ruttenberg]

I am using ColorPerfect. I may try viewscan doesn't have a profile for fuji and the target is the comes with is on a different slide film, kodak I believe. I would need to make a profile specific to fuji. I have the xrite color checker, but need to see if scanner reads the profile it makes. I suppose I could also apply profile in camera raw as well. I am still messing with a workflow for slides and bw negatives. I am good with color reversal. I will post up an image or two of slides Monday sometime. Next weekend I will scan and save as a non raw tiff and see how far that makes a difference. With my shot of Cholla I saved as raw, changed gamma to 2.2 in ps and it worked perfect. So shall see. File type may just depend on each image.

[Ted Baker]

I am using ColorPerfect. I may try viewscan doesn't have a profile for fuji and the target is the comes with is on a different slide film, kodak I believe. I would need to make a profile specific to fuji. I have the xrite color checker, but need to see if scanner reads the profile it makes. I suppose I could also apply profile in camera raw as well. I am still messing with a workflow for slides and bw negatives. I am good with color reversal. I will post up an image or two of slides Monday sometime. Next weekend I will scan and save as a non raw tiff and see how far that makes a difference. With my shot of Cholla I saved as raw, changed gamma to 2.2 in ps and it worked perfect. So shall see. File type may just depend on each image.

If your using ColorPerfect all well and good, you need to provide the correct input for that program.

However for straight to PS if I understand you correctly, then RAW scanning is not helping you. A raw scan has no matrix color transformation applied as well as no gamma curve applied. I don't use PS so I don't know all the details of its processing pipeline, but it sounds like a fudge.

[Steven Ruttenberg]

It is a fudge. The raw has the matrix already applied from the scanner, it is just that, the raw image, no recipe applied. So they generally look ugly till you apply a gamma of 2.2. In this case, it "may" be better to apply the recipe first. I will see how colorperfect does and compare.

[Ted Baker]

The raw has the matrix already applied from the scanner,

It was my understanding that no matrix has been applied to the raw data.