# Fence Visibility: Vertical vs. Horizontal

I see a new type of fence that has become popular. It has 4-5 inch slats that run horizontally and have a quarter-inch gap between them. This seems to allow a great deal more visibility than a vertically aligned fence with the same size slats and the same quarter-inch gaps. I’m wondering why this is the case. With a vertical fence, if I’m moving fast enough, I can get some view “through” the fence because it’s like a movie projector or persistence of vision or some such. But with the horizontal fence I seem to be able to see “through” the fence much better even when standing still. Why do the horizontal gaps allow for so much better “look through” than same-sized vertical gaps?

For one thing consider the position of your two eyes. You can see the same thing with both of them through a horizontal gap.

I think it has more to do with the thickness of the slats: when you look to the side of vertical slats they overlap at an angle of say 30° or 45°, depending on the distance between the slats and their thickness. Increase the distance between them and the angle you can look through may increase to 60° or more.
On a horizontal plane this does not play such a big role, as fences don’t go up or down more than a couple of degrees from the POV of person looking through (depending on how far away you are from the fence, obviously).

That is undoubtedly so. Even with one eye you can see better through a horizontal gap.

It’d be nice if we knew whether the OP was standing face-to-fence, or driving by 100 yards away at 60mph. The perceptual results are gonna be different depending on relative motion, distance, etc.

IMO, but semi-informed IMO …

Most of what’s interesting on other side is more or less level. So the one horizontal slat-gap that gives you a look at the cows or the house or whatever on the far side provides a much larger part of the salient scene.

Consider just standing still outdoors with no fence around looking at the scene in front of you. Your eyes see the dirt near your feet and a lot of sky. But your brain sees (pays attention to really) a scene just a few of degrees tall and 20 or 30 degrees wide.

If we did impose a fence in the way, clearly a horizontal gap in a fence would make that visual attention process go better than a fence with a vertical gap of the same size.

In most cases, these are fences 25-30 feet away moving past slowly (walking) or standing still.

I think its likely a combination of the fact that human movement is mostly on the horizontal plane, and anything to see behind a fence (i.e, a yard or a single story house )is mostly on the horizontal plane.

A horizontal gap provides a constant image when moving left-to-right, and the image it provides is of the entire yard.

A vertical gap provides a shuttered image when moving left-to-right that is going to be blocked 95% (4" slat / 4.25" center spacing) of the time when moving slowly or at something equivalent to 5% brightness when moving quickly, and a good portion of what you’re looking at is going to be a vertical slice filled with sky and the fence on the other side.

Are there enough factual replies for me to now say that the horizontal boards will make the fence look fat?

Only if you mean it in a good way.

But I kind of like the style of these horizontal fences even though I don’t like the visibility issue. I think they have a nice mid-century modern appeal which is amplified by the greater finishing of the slats, which makes them look fancier.

Agreed, and no fence-shaming here.

If you’re looking directly perpendicular to a fence, either one should be equally easy to see through. But you’re usually not looking directly perpendicularly, but at some horizontal angle. At enough of a horizontal angle, you can’t see through a vertical-slat fence at all.

Correspondingly, at enough of a vertical angle, you couldn’t see through a horizontal-slat fence, either. But it’d need to be an extremely tall fence in order to get that kind of angle.