While there are many ways to transfer an image from a photograph into a painting, I use only acrylic skin transfers in my work because I like the texture of the "skin" when I'm building up layers. Over the last three years, after making more than a thousand transfers for the Remnants series, I think I've ironed out most of the bugs in the process. As my method of working evolved it became important to use personal imagery rather than images appropriated from other places. Here's how I do it.
Use a laser printer or a photocopier to take a copy of the photograph you are interested in using in your work. You do not have to reverse text when using this technique.
Coat with medium
Coat the copy with gloss acrylic medium. I prefer Liquitex Gloss Medium and Varnish. I've tried other mediums, but they pale in comparison to the success I have with this product. When the first coat is applied let it dry to the touch, apply a second coat in the opposite direction. Continue to build up coats three and four in the same way. I've tried to get a good transfer in three coats and it is possible, but the skin is very fragile, and tearing is a problem when you try to remove the paper from the back. Five coats makes a sturdy gel skin which I recommend for your first try. I now have it down to four.
Dry the medium
I let the four (or five) layers cure overnight for best results. Have I been in a hurry and not waited? Yes! I have a small portable heater that I use to dry between each coat.
Place the treated copies in a bath of warm water for at least 10 minutes, but not over 20. I sometimes add a little fabric softener to the water; it helps break down the paper that has to be removed. Don't be concerned if the surface of the medium looks milky in water, it changes again when dry.
Remove Paper Backing
Remove the soaked copy from the water and place it face down on a waterproof surface. I do mine on my kitchen counter top or a piece of white laminate in my studio. Plexiglass or glass also works well.
Use the pads of your fingers in a circular motion starting in the centre of the copy and working outward to release the paper from the back of the gel skin. This is the part that requires patience. If you hurry or get heavy handed you will tear the gel skin. If this does happen, don't despair, when you use medium to adhere the skin to the surface of your work the tear is almost invisible.
If the paper starts to dry out, a spray water bottle will help keep it moist and workable. If it's really dry you may want to put it back in the water bath. The work is most fragile on the edges so slow down there.
Most of the paper comes off easily, but there is often a thin veil of paper left over the image. When this happens, I wet a facecloth or a sponge and rub gently to remove the last layer of paper. I have also used a soft nail brush or a scouring pad made for cleaning glass cooktops; it depends on how resistant the last layer is.
Dry the skin
Lay the gel skin, good side down, on a plastic shower curtain or plastic table cloth to dry. Some sites suggest wax paper, but I've had bad experiences with it and it can't be recycled. The plastic can be re-used many times, and it allows me to pick up the lot and transport them easily to the studio when they are dry. Wait for the transfers to dry thoroughly because it is easier to tear and apply them.
Once dry, they are ready to adhere to any surface you are working with. Check each to make sure there are not bits of paper left because they will create bumps in your application. Use a bristle paint brush to clear the surface of any nubs of paper left.
Choose the best medium for the task
I use matt gel, matt fluid medium or gloss gel or gloss fluid medium to adhere the image to my work. My choice depends on what I want to do next. If I'm choosing to apply glazes of paint in many layers or I'm overpainting all the applied images, matt medium works best for accepting paint. If I want to have vibrant colour and I am using little paint, I use gloss medium because many layers of matt medium really dulls the colour.
Getting a smooth finish
I use a bristle brush to smooth out the transfer onto the surface of the work. I've tried spoons, rollers but a good stiff brush has been best because you can wash it out after. Rollers get messed up with gel and then they get sticky.
If I get a bubble when dry, I stick a pin in it to release the air and apply a coat of medium to the top of it. Sometimes if I get a huge bubble in a large transfer, I've used a utility knife to make a small slit to release the air and apply a brush full of medium over the top.
These gel skins can be: torn and collaged throughout your work, layered over each other; sanded away in parts; or applied, dried and pulled off leaving the "ink" image on the board. If you want a particular part of the transfer to stand out (e.g., a face) coat that part with white paint on the underside and let dry then apply. You can get great ghostly images when you layer one on top of the other. You have to experiment to get the look you want. Many of the techniques I use came about through happy accidents.