The photos on your web site look good, are they taken with the same film and camera you are now having problems with?

There is a difference between 100 asa and 400 asa. 100 is good for bright days with a lot of light and the 400 will be good with lower light levels like indoors or shady and overcast days ect.Not knowing if you camera has shutter speed control and aperture controls makes a difference too.

Mike