problem with scanning slides

[kiwigray]

I am new to this so bear with m. I am on a Mac G4 1GHz running the latest version of the OS. I can get he Prime PF1800 Silver to scan, but the results are up and down like a yo-yo. When I start the program Silverfast up, it shows the origianl size as .7 by .8. Regardless of what I try to put into the scale box or the output box, they revert back to what they started with. I can't get them to stay at what I want, even though I lock the settings.

I must be doing something wrong. The resultant scan is too small to do anything with and then when I try to increase the size in Photoshop the result is poor.

Can anyone send me some simple instructions (I am a simple man). The "manual" says nothing about this. If someone couldlead me through the process to get the best result, i would be very grateful.

Gray

[LSI_Kratzenstein]

Maybe you have selected "Descreening" as Filter. This limit SilverFast to the double of the choosed Descreening resolution for scan. The scanresolution is : "scale * output resolution"
Please choose another Filter without descreening.

kind regards