I have already cut up the tomato. I ran my finger up in each section removing the liquid sections into the bowl. The liquid sections have the seeds. When your done you should have the meat of the tomato left. I then add water. I usually add the same amount of water that there is tomato liquid in the bowl. But i don't think there is a science to the water part. This tomato was called a Kellogg Breakfast. I bought it at a farmers market just for the seeds.
The second step i didnt take a picture of. I forgot. But just imagine the above bowl sitting somewhere kinda warmish. I use the top of my refrigerator. Let it sit there for a couple of days. It will start to ferment and stink. You want it to ferment because this is when the seeds will separate from their little gel sacks that they are in. I let this one sit for 5 days.
Pour your bowl of fermented tomato seeds into a strainer. Make sure the strainer will not let the seeds slip through its holes.
I rinse them with cool water for a while.
I put them on a piece of newspaper to dry back out before i put them in a jar or an envelope.
I have dried them before on a paper towel but because of how paper towels are made it was really hard to get the dried seeds off of it.