Things that work for me
I'm learning and improvising as I go, so I will report things here that may be of use anyone else starting out on printmaking. Hope it helps and would love to exchange notes with other people experimenting with these techniques.
Flat Pigments and Colours
I use a flatbed scanner (Canon Lide 400) to scan most artworks. You get great detail and colour accuracy.
Fluorescent, Metallic and Neon Colours
With fluorescent (and neon and metallic) pigments, dyes, paints, a CIS scanner will not read the right hue or colour. The best option, in this case, would be a digital camera, (NOT a phone camera, no matter how fancy and high resolution, it will just not be able to do justice to textures). Since my current prints are small, I am able to shoot them flat on the table with a 20 year old Canon Powershot G15, without any special lights, and with some basic colour correction on Photoshop. But will update as my artworks get larger.
I'm making stencils out of OHP sheets (or acetate sheets) of 75micron. They can be directly printed on a laser printer, which is very convenient. I use a Canon LBP2900, with a compatible toner cartridge. However, while cutting the stencil, the toner powder does come off very easily, so would recommend cutting on the back of the print, and wearing a mask to be on the safe side. The residue is highly static and does tend to stick to EVERYTHING and get everywhere.
I've also made stencils or masks out of regular paper, but these tend to be one time use only. For repeated use of signature stencils, I would recommend acetate sheets. I've also tried a heavier micron (100), they will last longer, but they are thicker on the gel plate and sometimes the paint doesnt get into the corners.