You must also be very careful not to get any tissue transferred to the top of the paper. Dry mount the paper to the area designated on the substrate. If you have trouble with the paper forming large bubble like pockets, you may have to press and dry the paper first. If the pins are affixed near the edge of the substrate, they can hang outboard of the dry mount press platens and not interfere with the mounting process. When the paper is mounted it should look like Figure 1.
Place tabs sticky side up on pins.
Position negative so the edge is on the sticky and the negative is positioned over the paper in its proper position. You may have to build an extension onto the negative using a piece of thin plastic or old negative. It should now look like Figure 2. By now you have probably gotten the point of all of this. What we have is registration system and a tamed piece of paper for gum or any other multi-coat printing process like gum over platinum, etc.