8. February 2002
Minolta Dimage Scan Multi Pro - 4800 dpi on 120 film

The Minolta Dimage Scan Multi Pro has a resolution of 4800 dpi optical when scanning 35mm film, but when scanning 120 film the resolution is 3200 dpi optical.
It is however possible to let the software scan at 4800 dpi on 120 film also, but then the resolution is interpolated.
The technical information from Minolta (can be seen here. Select "Details" on the "Scan size & input pixels" part.) says that : "...the scanner achieves 4,800dpi resolution through interpolation in the main scanning direction".
This could perhaps indicate that scanning 120 film at 4800 dpi is a bit better than simple interpolation(?)
Imaging Resource did a very fine and thorough review of this scanner and I must say that I thought I could see a bit more information in the 4800 dpi scans from the WG-18 Resolution Targets that they scanned.
But what about "real" photos?
That's what I'm going to test here.

Because of the nature of this test, in which I need high-resolution images to show the results, this page is HUGE. I'm sorry, but please be patient and wait for the images to download, because they are the real content of this article.

The Scans
I'm going to test in two ways: I will res-up a 3200 dpi scan and match it to a 4800 dpi scan and I will also res-down another 4800 dpi to match a 3200 dpi scan.
Re-sampling is done using Photoshop.
The following scans were all done in 16 bit mode and I used the color management function in the Minolta software to output to the AdobeRGB color space.
They were converted to sRGB and 8bit before publishing and they are all given the same amount of compression (the overview pictures are compressed more). All scans were made with the glassless film holder (you can see it here). Manual focus was used on the enlarged area.
All pictures are shown at actual pixel size and no sharpness or other filters were applied.

3200 dpi up-sampled to 4800 dpi


Rolleiflex 2.8GX, Fuji Velvia, Handheld.


Left : 4800 dpi. Right : 3200 dpi up-sampled to 4800 dpi. 16bit AdobeRGB, Manual Focus, Glassless holder, No ICE.

They are very much alike, perhaps the 4800 dpi scan (to the left) is a tiny bit more sharp(?).

4800 dpi down-sampled to 3200 dpi


Rolleiflex 2.8GX, Fuji Provia 100F, Tripod (no wind).


Left : 3200 dpi. Right : 4800 dpi down-sampled to 3200 dpi. 16bit AdobeRGB, Manual Focus, Glassless holder, No ICE.

They are also very much alike, again the NOT re-sampled 3200 dpi scan (to the left) looks a tiny bit more sharp.

Real 4800 dpi
What would real 4800 dpi look like? Is there any more information to extract?
If you set the scanner to scan "35mm Multi Format", you can scan a 24mm wide part down the middle of your medium format slide.
In order to make the comparison easy I've scanned the same part of the medium format slides.
I could of course also have scanned a 35mm slide in true 4800 dpi, but then it would have been more difficult to compare.


Left : True 4800 dpi. Right : Interpolated 4800 dpi. 16bit AdobeRGB, Manual Focus, Glassless holder, No ICE.

Wow! There is actually a bit more information to extract from this Velvia slide. It's not much and maybe a drum scanner would extract more, but there is a difference.

This was the Velvia slide, what about Provia 100F?


Left : True 4800 dpi. Right : Interpolated 4800 dpi. 16bit AdobeRGB, Manual Focus, Glassless holder, No ICE.

Well, OK yes there is more information or a few more details in the true 4800 dpi scan, but wasn't it more evident on the Velvia slide?
You can also compare with the 3200 dpi scan above.

Conclusion
In the up-sampling example there might be slightly (very slightly) more details in the 4800 dpi sample, but it's very little and perhaps a better up-sampling algorithm would level out this difference.
The down-sampled versions are also very much alike, perhaps again showing a tiny bit more information in the version that is NOT re-sampled - the 3200 dpi not re-sampled picture is perhaps a tiny bit more "sharp".
Bottom line is that I can not really find more information in the medium format 4800 dpi interpolated scans in this test. If there is more information in them, then it's so little, that I doubt is worth scanning at 4800 dpi.
If you need this kind of resolution for a big print, then you might as well get the 4800 dpi from the scanner, otherwise I wouldn't bother.

When scanning 35mm or a "panorama" part of a medium format slide or X-pan panoramas you can actually get more information out by using 4800 dpi, at least on a fine grain film.

4800 dpi or not - I still must conlude that this scanner is very capable and very versatile.

Links
My review of the Multi Pro scanner can be found here.

And don't miss the other articles about or related to the Minolta scanner:
• Scanner profiling on a budget 1/2 - [NEW]
• Scanner profiling on a budget 2/2 - [NEW]
• What resolution do I need?
• 4800dpi on 120 film
• Medium format vs. 35mm vs. Digital