Testing the EPSON V350 photo scanner: dpi (or ppp) settings

[angeche]

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To the administrator: please move it elsewhere if this is not the correct place.

 

I am trying to learn film photography with my Leica R8. But nowadays you also need to look at the digital world, Hence, I need to optimise the settings of my scanner when scanning my sildes (Fuji Velvia film).

 

The technical data of my scanner is optical resolution 4800x9600 (interpolated is 12.800x12.800, but what the hell is interpolated resolution?) , density 3.2D. I have used the scanner software and ACDSee Photo manager for editing the pictures.

Well, the dpi settings is the simplest one to test.

1) I have set some general settings: 48 bit colour, Unsharp Mask on, no restore colour settings, no grey correccion (assuming "claroscuro" is grey! my software is in spanish), TIFF.

2) I have scanned the slide at 4800 dpi, 3200 dpi, 2400 dpi (file sizes are 130MB, 57MB, 32,5MB, and pixe sizes are 23 Mpix, 10 Mpix, 5,7 Mpix).

3)I have also scanned the slide at 9600 dpi, but in order to have a manageable file I have only scanned a limited area (a bit bigger than the comparison one, see below). The file size is 28 MB and pixel size is 5 Mpix). I state this separately because the method used is different from the other pictures, and although I cannot imagine why this would affect results, the truth is that results are a bit puzzling (see below for results).

4) I have cropped the same area in the pictures: a detail of the house in the lower part of the picture. I have saved the results in jpeg files.

5) Since image size is different for the three, I have increased the size of all to 1102 pixels width (the wide size of the cropped picture at 4800 dpi). In the case of the scanned picture at 9600 dpi, I have decreased the size at 1102 pixels width. I stress this because, yet again, this may have affected the results.

 

I will try to add some images later on for the 9600 resolution since I am preventing from posting more than 4.

 

And here are the results: almost no difference in quality for the 4800, 3200 and 2400 dpi.

Here is the image used as reference.

And now the test. First image at 4800 dpi.

Second one, 3200 dpi:

Third one, 2400 dpi:

 

And the conclusions are that the dpi scanner settings do not matter too much.....or maybe yes! The 9600 image looks better. But I will post this later on.

 

Hope this is of interest to someone starting with film and scanners.

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[angeche]

Sorry to use this trick to post the 9600 dpi images. If this is incorrect, please delete it.

An image quality of the 9600 one that seems beter, although a bit softer than the others. I have added an additional picture for the 9600 using the sharpen options of the software.

 

9600 dpi image

 

I have use the unsharp mask with the 9600 dpi image:

 

Why on earth the 9600 dpi looks better, I do not know. Maybe it is the way I treated the image.

[Fernmelder]

9600 gives you a much larger file, but the resolution is not that much better than with 2400, I guess.

 

My V500 runs on 2400 usually.