I know the difference. What do you do when nothing gets the wrinkle marks out?
I have a Reliable 100, an ironing board that will pull steam through, a spray bottle, and another wet/dry iron. I've washed and not washed fabric (mostly cotton)
The actual wrinkle is flat. The fabric isn't pooched, the threads are straight, but the mark from the wrinkle is still there. It's like the fold in fabric. Sometimes washing the fabric removes the fold mark, sometimes it doesn't. The actual fold is gone, but the mark is still there. It isn't a fade mark, either. How do you get rid of that mark? I wind up using a lot of steam, pressure and spray, and the mark won't go. This makes it difficult for me to just "press" when nothing moves those marks. It's hard to believe the iron is even working! It's usually on light colors and solids.
I wind up stretching fabric when I don't want to.