I've left Kodachrome 64 and 200 slides in my Carousel SAV-2010 for up to 5 minutes with no apparent damage, either fading or warping. My slides date from the 80s to about 5 years old and none are showing any obvious fading despite having been projected 10+ times in a number of instances and I would estimate for an average of 20 seconds each. I also have some earlier Kodachromes in card mounts from the late 50s to early 60s which look as good as new though I rarely project these myself.