Coating / waxing / oiling old wood without darkening it

Question

I make sculptures (well, I try to, anyway) with old wood that I find in the forest. I strip and sand them heavily until I reach the "good" wood underneath the bad parts, but the remaining wood is still usually kind of porous, and has a dusty look, although it is actually clean. At that point, the wood has a brownish color, as you can see in the picture below, but it is not very dark. The color is very uneven, however, with lighter parts and much darker parts. But overall, apart from the dusty look, the color is fine.

Then, as soon as I try to apply any kind of finish to get rid of the dusty surface (clear varnish - spray or brush, linseed oil, wax, anything), it gets much darker, and it ruins the whole thing. I think it is because, as it is porous, the finish goes into the pores and reflects the "darkness" inside them, or whatever. I also somewhat tried fancy stuff like oxygenated water to lighten the color, and some mixture of white crayon and oil, without success. And any attempt to use some light-colored translucent paint makes it loose its natural look.

I would like to find a way to make the piece of wood look less "dusty" (it doesn't have to be shining bright, but just look "finished"), revealing the wood grain as much as possible, still looking as natural as possible (painting them isn't what I want), without the wood turning into a dark brown/almost black color for the most part.

Is there a solution for this?

Wood after sanding, no coating. Color is acceptable, but looks dusty/dull.

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Wood sample, half waxed (neutral wax, very slightly yellowish - but whatever coating used would get approximately the same result)

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Other piece of wood, coated (coating based on lineseed oil and some fancy stuff I tried to mitigate the problem, which did not improve anything). Way too dark, except in a few areas.

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Answer 1

When you put a clear liquid on the wood, the wood looks darker and the grain has more contrast, but you aren't actually changing the color of the wood. That's why bleaching solutions like oxygenated water don't fix it (the color can look bleached once it dries, though). Different clear liquids will produce greater or lesser of this effect depending on how well they're absorbed by the wood and their refractive index.

There are a few things going on. The wood starts out looking "dusty" because the surface is full of microscopic irregularities, no matter how much you sand it. That randomly scatters some of the reflected light. If you coat the wood with a clear finish that fills the irregularities and has a smooth surface, the surface looks polished and the wood details become more distinct.

If it was a flat board, you could sand it with progressively finer sand paper up to an extremely fine grit used for polishing (you'll never get wood to look like a mirror, but you can get it less matte). That's tough to do uniformly on an irregular surface like the wood in the picture. But the smoother you can get it, the less of a problem you'll have trying to correct that issue with a coating. If you can get it reasonably smooth, buffing it can help.

Adding the right kind of finish in the right amount can make the surface less matte without being glossy. That will make surface details more distinct and the color will look a little more saturated. It can be a tough balancing act to achieve your ideal level of looking finished but still natural.

People who do fine woodworking may have some experience with what finishes work best for this, but doing it on wood in its natural, rustic form is a special case. It would be best to get advice on that from people with experience doing exactly that. Hopefully, Arts & Crafts has a few readers who do it and can share their expertise in an answer.

The problem of the color getting much darker when you put a finish on it is different. The color of the wood isn't actually changing. The process is similar to what happens when concrete gets wet or perspiration makes a dark area on your clothing. Some of the light reflecting off the surface gets reflected back again by the underside of the liquid layer, and the liquid changes the angle of the light hitting and reflecting off the surface. Less light is directed to your eyes, so the area looks darker.

As the liquid is absorbed or evaporates, the surface layer disappears and the color goes back to normal (although the wood grain will remain more distinct for a longer time because differences in porosity affect how much liquid is absorbed).

If you clean the surface with a liquid that evaporates, the color will quickly return to normal. If you rub in an oil finish, the oil will eventually get absorbed into the wood and the color will return to normal, but much slower.

A finish that wets the surface of the wood and hardens will lighten a little as the solvents evaporate and any oily components get absorbed into the wood. It may also lighten a little over time if it shrinks and gets some microscopic separations from the wood or its optical characteristics change. If its surface gets scuffed, it will scatter light like the original wood surface and look lighter. But at least some amount of darkening effect is likely to last pretty much as long as the finish remains.