maybe because you should check (and set up) the detection sensibility on image master platinum software before the Tiff conversion.

You could try to save your image as a tiff file if your scan program enables that in the first place and avoid using a converter program.

I am not familiar with the Lab Scan instrument but as long as you are using the software associated with the scanner for converting to Tiff, all intensity information should be retained. In that case, it might just be a question of adjusting the display settings in Image Master. It might default to show the maximum theoretical bit value as pure black, and 0 as pure white. If your maximum measured value is e.g. 20% of the theoretical maximum, your image will look washed out and smaller spots will "disappear".

Thank you friends, i will try your suggestion.