Q-factor and filesize

[Robbafett]

Hi!

Before I bought silverfast I used NikonScan, and there I scanned slides at :
3600 dpi and the filesize usually ended up on 20 Mb.

Using silverfast with the same resolution gives me:
~5 Mb/picture (Q factor = 1.5), and even changing the Q-factor to 1 still gives me about 5 Mb at 3600 dpi.
Jpeg quality is set to the highest in silverfast.

I would like the same quality/filesize as with NikonScan, how do I do it? What´s the reason for the much smaller filesize with silverfast? Has this anything to do with optical resolution vs interpolated resolutions?

Please help!
Kind Regards,
Robert

[LSI_Morales]

Dear Robert,

The Q-factor does not have anything to do with the filesize, it is basically a multiplier in a matematical algorithm used to make the conversion from analog signal to digital. The optimal Q-factor is 1.5

I can not really explain you why the difference in filesize between NikonScan and SilverFast because we do not know how NikonScan works as well as your settings there and in SilverFast.

However I believe you might have saved your files as TIFF in Nikon which is an uncompressed file type, this generates bigger file sizes.

I suggest you try saving your files as TIFF files in SilverFast, this will give you a better quality endfile which can be used as your digital original for any post production.

Cheers

[Robbafett]

Hi Alejandro and thanks for your reply,

I can not really explain you why the difference in filesize between NikonScan and SilverFast because we do not know how NikonScan works as well as your settings there and in SilverFast.

I understand it´s a bit tricky to compare things when you don´t have all the info.
However in NikonScan I saved all the pictures as jpeg, as I do in Silverfast, highest quality in both programs and you can´t really make too many filesize related changes in either programs. I kept all the settings as "standard", 3600 dpi, and highest jpeg setting, it just feels weird with the difference in filesize between the both programs. A thought is if Silverfast compresses the jpegs harder than NikonScan?

I´ll try saving in TIFF instead...

Kind Regards,
Robert

[LSI_Morales]

Dear Robert,

NikonScan is an older application, most likely it has some old algorithms which created such files, the math algorithms also evolve as time passes.
That is my guess about the difference about file size.

Cheers