Debate of the day - Jane wants to replace the curtains (which need replacing as they have a floral pattern and colour which clashes with other furnishings in the room) with slatted blinds. She is talking about wide wooden slats. I am viscerally against this idea and I wasn't sure why so have thought it through.

I think that there are several things going on here in my head to do with the pattern of bedroom and the characteristic actions and feelings associated with a harmonious sleeping space.

 

Firstly it is a given that a bedroom, like any inhabited room, benefits from having windows and an out-look. We like to be able to be aware of the outside even while we are inside relaxing.

Secondly it is a given that a bedroom, perhaps more than any other room, needs a means of covering the windows. Partly this is for privacy, we don't like to feel that the outside can peer in to a space where we may be exposed and vulnerable and where we may be engaged in private actions. This applies even if it is virtually impossible for any person outside to position themselves so as to see in. There is always the nagging fear that a passing parachutist might drop by at the crucial moment. Also it is a means of moderating the extent to which we are aware of the outside - sometimes we might like to lie in bed watching the clouds and birds pass by, at other times we may wish to exclude some of the daylight.

Of course a variety of different window coverings can be devised to meet these needs. In warmer climates often louvred external shutters might be used to allow an airflow whilst maintaining privacy with the window inside open. In our climate we more usually achieve this on the few hot summer nights by having an opening pane and adjusting the coverings on the inside to the window to allow a compromise between airflow and privacy. Of course slatted, or Venetian, blinds can achieve this just like an external shutter whilst also providing variable levels of light control.

There is, however, much more than this to internal window coverings in a bedroom. Two particular aspects come to mind immediately - the first is material and the second is patterns of use, both active and passive.

Material is quite simple. In our climate more often than not we need our bedrooms to have a feeling of warmth. Using fabrics for the window coverings is a benefit here. Of course you could make blinds of softer material - use wooden slats with a tactile surface rather than smooth plastic or metal, cover the slats with textured fabric, use a roller or Roman style blinds which can be made of fabric rather than slats. The real benefit, particularly in winter, comes from folds of gathered material which deaden draughts and provide a softer warmer feel to the space.

Of course lined curtains, well gathered, trap air between the layers and in their folds providing excellent insulation properties on cold winter nights. Blinds do trap a layer of air between the blind and the glass (as also do curtains), but the insulating value of the 2 or 3mm of solid material, with gaps between the slats allow heat to migrate with the air from one side to the other, is going to be far lower than that of two layers of heavy fabric gathered in folds 30mm or more deep.

We 'know' this intuitively which is why a room with blinds will have a cooler more open feel than a room with heavy drapes. Sometimes coolness is good, sometimes we need warmth.

Moving on to patterns of use we can think about both passive and active uses of window coverings.

Both blinds (lifting and slatted) and curtains can be adjusted to reveal more or less of the window and the view beyond (in either direction).

Curtains and lifting blinds as they are opened reveal a slot of increasing width. Vertically, usually from the middle, in the case of curtains and horizontally from the bottom in the case of lifting blinds.

From the point of view of a person looking out this is a crucial difference - a vertical slot allows a view out whether you are lying, or sitting, or standing. A horizontal slot provides a very different view in each position. It also changes our awareness of what someone outside looking in can see. With a vertical slot it is easy and comfortable to conceive the external view - if I can see someone through the gap then probably they can see me, if I can't see them then probably they can't see me. With a horizontal gap it is much harder - standing up the person outside may be invisible to me but might have a very clear view of me from my waist downwards. I can control what is seen through a vertical gap by moving from side to side - much harder to control with a horizontal gap.

Again we intuitively know this and it makes us feel more comfortable in one situation than another. In fact the anticipation of the potential inherent in the different forms of opening makes the room a more or less comfortable space whether or not the openings are open. In some spaces - kitchens, dining areas, informal rooms this might not matter much, but in a bedroom it becomes an important factor.

Turning to slatted blinds the situation is even worse for a bedroom. Now, whether the slats are vertical or horizontal, there is no hiding. Once they are open even slightly then the whole scene inside the room is exposed to outside view - subject of course to relative light levels and how close the viewer each side is to the slats. One advantage of slats is that because they are angled and to some extend overlap it is possible to initially use them very effectively to control the light levels entering the room and once they are angled enough to permit a view through the view is only in a certain direction. For this reason vertical slats can feel more comfortable than horizontal ones. As noted when comparing the gap between partially opened curtains and the gap under a partially raised blind we are better able to assess what is revealed through a vertical slot.

A common passive use of window coverings in a bedroom is the situation of lying in bed with the curtains partially open allowing the day to be assessed, the weather, the light, the sound, the air clarity, the movement as preparation for fully engaging with it. A transitional opening into the new day. With curtains, or a partial raised blind, what is seen through the gap is clear, and we know that we could open them fully and have the whole picture. Slatted blinds on the other hand remain a barrier even when fully open - we can see the full extent of the window but they remain a visible barrier between us and the outside, cutting us off and preventing us engaging with the day.

Turning to active use of the different type of window coverings we see the most dramatic differences in gesture. It is our gestures which define our relationship to the world. With a blind, whether slatted or lifting, we interact with it through a mechanical device. We pull on a cord, or turn a knob, or twist a lever to operate the blind. The range of expression in the gesture is strictly limited by the mechanical intermediary.

With curtains however we use a horizontal sweeping gesture - arms moving apart to open them in a gesture of welcome, arms drawing together to close them in an embrace. These gestures can be amplified or restrained, we can fling the curtains apart in gay abandon letting the world flood in to our lives, or we may chose a gentle and considered movement slowly closing out the gloaming and turning inwards to the room and the bed.

Finally, this natural harmony between the covering device and the gesture it invites is seen again when the window is covered by closed blinds or curtains and we wish to simply peep out without opening them. For slatted blinds we can sometimes bend the slats to peep between them, but this is an aggressive gesture towards the material of the slats, rudely distorting it and expecting it to fall back into shape. With a roller blind we can crouch down and raise it slightly to peer underneath it. Only curtains invite a natural way to slightly part the coverings conveniently allowing just our eye to look through and then withdraw and the fall naturally back into place.

Curtains, in a bedroom, in our climate, are simply the most appropriate form of covering for a window pane. They work naturally and harmoniously with our needs and experience of the space and enhance a room. For us blinds can only intrude and be an obstacle.

Elsewhere in the house blinds may be appropriate, but not in the bedroom.

Now the challenge is to find a fabric which will harmonise in the room with two very different patterns of duvet cover that we have in use.