You are seeing what we refer to as 'dishout'...and it is a sanding issue. Walnut is very difficult to sand flat. Each of us have a favorite sanding method to get a flat result. I use a machine, similar to a terrazzo grinder, called a Lagler Trio, as the final machine; it never fails in giving an absolute flat result. You will notice dishout and any other sanding anomaly on these dark floors. You will also notice every scratch, dust particle, pet hair and piece of lint.

When we stripped away all of the layers (9) of linoleum and sheet vinyl in our kitchen, we found unfinished pine flooring which had been installed diagonally to the original floors which are underneath. Because we have hardwood all the way through the house my wife really didn't want the same wood look in there too. We debated on several options but neither of us really wanted to cover the floors back up. Instead, we painted them. I used latex glazing thinned down to the point that the grain of the wood would still show through. I then taped off the floor to form a pattern of 18" squares in a checkerboard pattern. We painted half of the squares green and left the other half glazed. The flaws, cracks, and knots show through even on the painted squares. When it was all painted and completely dry, I distressed the finish with a sanding block. I knocked off some of the edges and created places where the natural color of the wood could show through. I then added five coats of water based poly. It looks like it has been there since 1880 when the house was built. It turned out just as my wife wanted, which is what really matters.

If you can, you can. If you can't you can't. Be OK with EITHER scenario. Give it a go. Take a SAMPLE of the wood you are going to be using and go shopping. Bring HOME a sample of what you think might work. Sit with it in your house (I know it isn't the right house but it isn't in industrial lighting during the day...so it is much better than 'guessing'). Move it into the dark areas and then back into the light. If you have a basement, then take it down there. Leave the REAL WOOD on the stairs (ideally you will run the WOOD on the STAIRS to the basement...and then start the vinyl on the basement slab). Then lay the sample vinyl on the floor below it. Turn the lights on...and off...etc. If you FIND a good match, you will need to know HOW LONG it has been in production. Most man-made products (like vinyl AND engineered hardwoods) have an 18 - 24 MONTH run. After that you will never find it again. So....find out, from the manufacturer, how LONG ago they RELEASED the vinyl colour. That way you can PURCHASE IT IMMEDIATELY or you can WAIT a few months until you need it. Eitherway, always look at 10% extra. That will get you a significant square footage for the time the laundry drain backs up or the hotwater tank 'lets go'. I like to see 100sf of extra (about 5 boxes) for 1000sf of measured floor space. Believe me, over 25 years, you will ABSOLUTELY NEED IT. I can guarantee it.

Ill throw my suggestions out there. I wouldnt use anything that builds up on the floor, which eliminates everything. A lot of products build up and cause a haze that isnt easily removed. Hardwood and water never mix, if you have to mop, use a microfiber pad on a swifter like mop, wrung out until its just damp, if it doesnt dry very quickly, its too wet. Some people use steam mops but you risk damaging (cupping) the floor. I used to run my roomba every other day to keep the dust off the floor and microfiber the floor weekly. Keeping dust and dirt off the floor is key. Dark floors are beautiful and rich but the maintenance stinks.