We are designing a user interface for the roller shutter users. The ones in question are exterior rollers. These have tiny holes between the slats. You can shut the roller with the holes visible (so some of the outside light still sneaks into the room), or close it fully, enabling you to feel as if you were a mole.


We are going to use the time taken to reach each state as captions for fields in the user interface, so they should be as concise as possible.

We have not agreed on how to state these questions. The best we've got is "What is the time to shut with unsealed blinds?".

Therefore, I have three questions for you:

1 What would you call the state of roller shutter covering the whole window but with the "holes/rays" visible?

2 What would you call the time required to achieve this state?

3 What would you call the time required to close completely?

  • 1
    'Loosely shut' and 'shut tight'. / 'Time required to shut loosely' / 'Total time required to shut tight.' Commented Aug 9, 2021 at 16:20
  • This might be more a user-interface thing than an English language one, so I’m putting this in the comments section. Consider providing the picture above and one for the tightly closed state. Label them, then have fields along the lines of “Time(A)” and “Time(B)”.
    – Lawrence
    Commented Aug 9, 2021 at 16:39
  • If you want to know the time it takes for the bottom of the shutter to reach the bottom of the opening, ask that. Do you want to know the time it takes for the shutter to go from completely open to completely closed or the time between when the bottom of the shutter reaches the bottom of the opening and when the shutter is completely closed? Being precise is more than just choosing the right word to describe something.
    – ColleenV
    Commented Aug 9, 2021 at 17:42
  • 1
    1 How long does it take for the blind to reach the bottom?” 2 Time to reach the bottom. 3 Time to blackout.
    – Greybeard
    Commented Aug 9, 2021 at 19:20
  • 1: splayed, 2 & 3: and differential (presumably you can set the number of seconds it takes)
    – Mazura
    Commented Aug 10, 2021 at 0:34

8 Answers 8


For captions and concise usage, I suggest nearly closed, tightly closed, time to nearly close, time to tightly close or, if shorter is needed, nearly closed time and fully closed time. Shut IMO works in nearly/tightly shut, but I would use close the shutter rather than shut the shutter.

You could explain at the first usage that nearly closed means almost closed, "with sunlight peeking through the holes."

With regard to questions: What is the time required/needed to tightly close the shutter? or What is the time it takes to nearly close the shutter?

I lived in Italy, Land of the Roller Shutter, for many years, and tapparella socchiusa is the term used there for a shutter that's not completely closed, as the illustrations show.

Tapparella in Alluminio Coibentato con Asola Larga da 18cm per una maggiore illuminazione e ricircolo dell'aria a tapparella socchiusa

The adjective socchiuso itself is often translated using ajar or slightly open. However, ajar in this case gives me the sense of open space under the bottom of the shutter, as might slightly/partially open. Other short descriptive phrases I can think of don't work when used before the noun time.

  • 1
    Good answer. My only observation is that “loosely closed” might be better than “nearly closed”. From a security standpoint, both states are “closed”.
    – user205876
    Commented Aug 9, 2021 at 17:59
  • That works and did occur to me. "Nearly closed" might work a tad better before the word time.
    – DjinTonic
    Commented Aug 9, 2021 at 18:10
  • s/peaking/peeking
    – mcalex
    Commented Aug 10, 2021 at 5:59
  • fully closed time and nearly closed time do not work in brochure-type language.
    – Lambie
    Commented Aug 10, 2021 at 16:27
  • I don't know that the "user interface" the OP refers to is a brochure. It could be a more technical document. At least that was the impression I got.
    – DjinTonic
    Commented Aug 10, 2021 at 16:48

'Soft Light Closure' and 'fully dark closure'.

Defining Terms to make your document easier and clearer.

I would give the state of 'light peeking in' a name of its own. to make it easier to talk about it.

I mean, I'd give it a product name like 'Soft Light' or something like that. Then, you can easily talk about 'Soft Light' closure. And you can also then talk about 'fully dark closure' without tying yourself up in knots.

You'll then be able to refer to the 'time for Soft Light closure' and the 'time for fully dark closure' also, without tying yourself up in knots.

You'd start off your document with something like this:

There's a special way of closing our blinds so that light still still peeks in - the shutter is fully secure and closed but some light comes in through unique small apertures. We call this feature 'Soft Light', and we refer to 'Soft Light Closure' when your shutters are like this. When your shutters are fully closed, and completely dark (ie, no apertures are open) we call it 'fully dark closure'.

Having stated this once at the start, you can just refer to 'Soft Light closure' and 'fully dark closure' continually, after that.

Often, legal documents use this technique - they define certain terms up front - and then refer to them in exactly the same way throughout the entire document. This method is very simple and clear, and I feel it is also well used in brochures or technical documents of the kind that you seem to be making.

You refer to your 'terms' up front, in the introduction - and then refer to them throughout. They can even be listed as 'terms used throughout this document'

As you do seem to have a unique 'product feature' here - why not give it a name?

Note: 'Soft Light' has capitals as it is a suggested 'product name'. 'Fully dark closure' does not, as it is a normal feature of shutters, not a product name.

Here's a good, more detailed description about how the concept of defining terms, described here, is used in legal documents.



Although used mainly for doors and flat shutters the term ajar can reasonably be applied to a roller shutter with a setting like this.

According to Merriam Webster and other sources ajar is derived from the prefix a- (as in aloft, afore, above etc) and the Old English word charr meaning an angle. As the movement of the roller feeding out or pulling in the shutter is a rotation through 360 degrees of angle it seems perfectly reasonable to refer to partly opened roller shutter as being ajar".

  • The problem is that "ajar" indicates not-closed. From the description, their roller door is not only closed but locked, while still in the mode that allows some light penetration. The purpose being to be able to close the roller door, lock it, and switch off the interior lights wile still allowing enough light to filter through to enable the person to see what they are doing inside.
    – PcMan
    Commented Aug 10, 2021 at 6:41
  • @PcMan If you have a door fitted with a security chain or loop then the door is still secure when it is 'ajar' so long as the chain or loop is in place. Also my UPVc widows can be opened slightly to allow air to pass but still secured with the catch and the catch lock. I would have no problem with saying that they are ajar.
    – BoldBen
    Commented Aug 10, 2021 at 17:59

1 What would you call the state of roller shutter covering the whole window but with the "holes/rays" visible?

For marketing purposes, I like @Jelila’s idea of coining a term for this partial state of closure in your interface. I suggest “Starlight" mode, to contrast with the fully closed “Dark" mode.

2 What would you call the time required to achieve this state?

The time taken to achieve the partly lit closed state could be specified as, “The time taken from completely open to reach the partially closed Starlight mode is x seconds/minutes”.

3 What would you call the time required to close completely?

The time taken from completely open to achieve the fully closed state could be specified as, “The time taken to reach the fully closed Dark mode is x seconds/minutes”.


Closed and shut could be mistaken for fully extended as a barrier against entry by a person rather than the desired meaning of "letting some light in/not letting any light in".

You could say

"Time to full occlusion", "Time to partial occlusion".

"Time to zero light", "Time to 5% light". (whatever the percentage may be)

"Time to full dark", "Time to partial light".


Answering the main question, the terms 'ajar' and 'closed' could be applied to the gap visible below the shutter (the extent to which it is unrolled) so I suggest, from Lexico


Allowing light, but not detailed shapes, to pass through; semi-transparent



Not able to be seen through; not transparent

  • This is perfect.
    – Davo
    Commented Aug 9, 2021 at 18:55
  • 3
    These terms refer to actual objects; not to how light is filtered between them. So these don't work here.
    – Lambie
    Commented Aug 9, 2021 at 21:29
  • I think that these terms would work if this was one of those "dimmer" window treatments where you can adjust the opaqueness of the glass with a dial, since the actual material is changing its state (in terms of how much you can see through it.) But you wouldn't say that venetian blinds (for example) become "translucent" when you adjust them so they're mostly closed but still allow in some little bit of light. Commented Aug 9, 2021 at 22:01

I would think “sealed” and “unsealed”. The shutters are sealed against the light, or they aren’t.

So they can be open, closed but unsealed, or closed and sealed. Once people know the terminology, you can drop the “closed but/and”, and just say sealed or unsealed.


These are roll or rolling shutters or roller shutters. Roller is the word in English for a round cylinder. These are not that overall but they have a roller at the top. The shutters are retractable and can be rolled up and down on a cylinder at the top of the shutter but each metal slat is NOT a roller. These are also called louvers. The shutters are mounted on a roller (cylinder) at the top of the window.

Next: we say:

fully retracted shutters, or rolled all the way up
fully extended shutters, or rolled all the way down

TIME: full retraction time full extension time

Then, the slats can be angled to let in some light or keep it all out:

to angle them shut or open, or to partially angle them.

  • angling a little, angling a lot, no angling

minimum angling, maximum angling, no angling

roll shutters

  • 2
    They aren’t really angled though. From what I can tell they are similar to tongue and groove construction where there are some holes in the tongues. When compressed completely the tongues are fully contained inside the groove of the adjacent slat. When closed but not compressed there is some play between slats and the tongues with holes are visible.
    – Jim
    Commented Aug 10, 2021 at 0:08
  • 4
    It's not true that 'roller shutter' is not used for a shutter made of flat slats (or louvres) which roll up onto a large roller at one end (at least in the UK). No one, to my knowledge makes shutters out of rollers but this sort of shutter is called a 'roller shutter' by makers and installers such as this one
    – BoldBen
    Commented Aug 10, 2021 at 3:24
  • @BoldBen is right. "Roller shutter", which is what they're called, refers more to how they work (rollers running in channels) than to the shape of the visible parts. Downvoted partly because the answer is mainly a (wrong) comment on the (standard) terminology in the question, but also because there's no angling involved so the actual answer in the answer is incorrect.
    – Chris H
    Commented Aug 10, 2021 at 7:32
  • @Jim The metal cross-bars are called slats. Compression is not the right word. Those slats can be angled open or can be closed.
    – Lambie
    Commented Aug 10, 2021 at 15:27
  • 1
    @Jim Ok, if they don't angle like plantation shutters, the OP didn't explain this very well. You think the opening between the slats can be made wider or narrower without angling the slats? And only by decreasing/increasing the opening between them without any pivoting? :) I have had to edit poorly translated shutter stuff in English and therefore am interested in how you see this. (Jim, I never thought you were confrontational. I wish people here would just talk straight like you did and not pussyfoot. :)
    – Lambie
    Commented Aug 10, 2021 at 15:40

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