How can I lighten old heart pine paneling in my den?

White Wash them

Instead of changing the wood, can you paint your picture frames to white and have white throw pillows, etc.? White accents throughout the room might be just what the room needs.

Good luck!

Hi Gayle first thing that came to my mind was a white wash where you take basic white acrylic paint and mix it 50/50 with water before applying it with a big brush. You could also take straight white paint and a big brush and just do a "dry brush" over everything where you use very little paint on your brush and just work it lightly.

I'm guessing that the pine has been coated with varnish. You might try stripping it in a small area that's not very visible. That would lighten it. But do a test area first.

White wash is a great idea!

There is a product that you buy called "wood bleach". I tried it to remove heavy staining on unpainted doors that had been in a shed that had roof leaks. Lightened but did not remove the stains. Might be just what you are looking for.

You can actually use hair bleach. Test the mildest volume in an area that's not visible. Brush with foam brush (heavy but not so that it's running down the wall) and cover with plastic wrap. Tape all around. Press wrap into the bleach -- gently. Do not use plastic bags. Leave for 1 hour and wipe off. If it needs to be lighter, reapply and leave overnight. This method will work through the finish. I've used this method on black water and urine marks on wood floors.

My entire living room and dining room is wide, old-growth heart pine planks. Something that makes a huge difference in the space are the fluorescent strip lights on the walls. I’ve never seen them anywhere else, but they are similar in appearance to a box valance that you would see over a window. They wash the walls in lots of light. I have them over windows for nighttime and on interior walls as well, where they light up artwork hanging beneath them. They throw enough gentle light that lamps are not needed at all for reading or knitting

You could do some "testing" on some other wood and try doing a white wash of paint. Mix equal parts of paint and water and brush on and then use a soft cloth to remove some of it until you get the look you love. This would take more time than money but could result in a very comfortable and lighter feeling room while keeping the special wood.

If those old boards are shellaced, you are going to have to sand them first. Then you could white wash it to not lose the grain. You will have to treat the knots with Zinseer BIN to prevent them bleeding or clear shellac.

Other option would be to wood bleach the boards once the old shellac finish is removed.

Another option is to run LED strip along the top the wall around the room, and add a bit of cove trim to hide the strip. They sell kits cheap and they have remotes for turning on and off, or changing color. https://www.youtube.com/watch?v=vtg2GUHkrmM

Give them a colour wash or maybe a antique wax look?

Hi Gayle, you could try this product,

https://www.youtube.com/watch?v=QcBiVjNJh4A

https://www.youtube.com/watch?v=LThlDMKfheE