I have been try to figure out what should be simple... but for some reason seems to be about impossible. I was wondering if any other SilverFast AI Studio/CoolScan 9000 user has figured it out.

I am scanning 35mm and 6X6 transparencies. I would like to scan for maximum quality/enlargement size. I mostly scan full-frame with little or no cropping.
I am trying to figure out what settings to use to scan at the Nikon 9000 scanner's maximum optical quality without interpolation. The Silverfast techs have said that 4000 dpi is actually over the true optical resolution for the 9000 and suggested that 3600 was a more realistic figure.. maybe even 3000 dpi.

I am scanning using the 48 Bit Color setting. Not HDR.

In SilverFast's "frame" options field:

I have set both "scale %" fields at 100.0

I must assume that the data in the "original" fields is generated by the dimensions of the cropping frame on the image preview.

I have tried to set the output fields... but I am not sure how it works.

My Q factor is set at 1.5 with "screen" reading 2400

The dpi figure I have typed in as 3600 as the slider will not give me that figure.

Does anyone know the magic formula or input sequence I need to follow generate maximum quality scans from 35mm and 6X6 transparencies?

Why can't you specify 4000 dpi and 16 bits? Sounds like you are getting carried away with theoretical advantages.

Nikon scan is simple to use and yields excellent results. Siverfast may be much more sophisticated, but is it helping or hurting what you want to do?

If I remember correctly, the Q-factor (which I always found a bit confusing and redundant) should be left at 1.0. If you set scale to 100% and the maximum true resolution (what ever that is for the Coolscan) you will be using your scanner to itīs full extent. Setting 1.5 for quality factor actually means you are interpolating. This feature is a "quick" way of setting your scan size when knowing what the final output size is. But if you are maxing optical resolution and set Q-factor above 1 you are asking for resolution your scanner can't deliver. Make sense? (I don't blame you if you don't understand my explanation here. Especially since I'm not 100% sure I remeber it correctly).

I haven't looked at Silverfast in a long time (I didn't like it much), but let me say this. The "native" resolution of the Nikon 9000 is 4000 dpi. You should specify 4000 dpi. It might not fully attain 4000 dpi (for one reason or another), but you will get the maximum out of the scanner. If you specify something lower than 4000 dpi, like 3600 dpi, you will get an output that is proportionally lower than 3600 dpi, and the scanner won't be operating at it's native resolution.