Am I using foil the wrong way round?

If you count the nicer suede side as the 'right side' then that faces the window on these JL curtains. The 'right side' of the curtain fabric is obviously facing the room. The hems face each other in between curtain and lining - two 'wrong sides' together, hems facing with the lining a bit shorter than the curtain.
If that makes sense!

Great, I think I understand. Mind you, My brain goes all fluffy every time I try to make curtains so will need to keep coming back to re-read this!

The only blackout ones we have are from JL and in the small bedroom (not expensive ones, they are for a child's bedroom).
The suede side is outwards facing the window, hem to hem on the inside.

Sorry. not a Scooby Doo, we don't have any black put curtains.

Mine are suedey side outwards as well, partly because of the way they're hemmed but also because the 'other' side is a pale greyish colour which doesn't go with anything. The suedey side is beige.

just looked at my curtains , they have the hem turned up onto the suede side so that is the side turned to the curtain ............ otherwise it would look untidy from the outside and we don't want neighbours sniffing , do we ?

Okay, now that the foil is sorted, please can anyone (*Pompa*?) tell me which way blackout curtain lining should go? Suede-y side to the curtain or smooth side to the curtain?

Irrespective of the foil dilemma, I'm loving that The Galloping Gourmet, Graham Kerr, just got a mention. I loved him. Re the foil, I kind of understand the logic of shiny side in, but I'm going to be reckless and carry on using shiny side out. Hard to change the habits of a lifetime.

Perhaps if the oven has an element glowing red or white hot like a grill it might reflect it, but most heat in an oven is convected through heating the air in it, not radiant, so I am not sure that reflecting it is all that relevant.

In a grillpan, under the meat being grilled, reflecting the heat back up from the shinier surface onto the underside of would make sense - but does it really do that?

I always do shiny side in because it will reflect the heat otherwise, or so I was told years ago?

Whichever way works for you I suppose

I have just seen an advert for the stuff and on the top right hand side it says use dull side inside.

No seriously pompa I was grateful for the info. Needed to be reminded about egg sucking.

Jud... Sorry if I'm teaching my granny to suck eggs.

Nana3. Yes silver foil would reflect radiation (the Sun) very well.. This is why we can get sunburn from snow.

pompa you are such a mine of information. Thank you for reminding me of the basic science. Every time I come on to GN I learn something ?

under the chin wrinkles... oh yes!

<eyeroll>

I once saw a person sunbathing with silver foil reflecting ( pompa ?) the sun to get under her chin brown. Ooo er mrs !!!

Yes that's what I mean silly me

It is not supposed to matter which way around!

For the technically minded, there are three ways heat can transfer :-

Conduction -when you put your finger on a hot pan (ouch) that is conduction.
Convection - this is the transfer of heat through the air - an electric fire
Radiation - this is usually infrared radiation. This is a type electromagnetic radiation eg The Sun.

Foil is very good at conducting heat, either way hot>cold or cold>hot. It will prevent convection because it forms a barrier and it will reflect radiation. But an oven primarily works through convection so the silver/matt side will not make much difference.

A thermos Flask works because it prevents all three types of heat transfer.

Glass is a poor conductor of heat
The silvering reflects radiation
The vacuum prevents convection.

Pompa has hit the nail on the head, the difference in finish is just a by-product of the way it's produced, not for any performance reason:

"Aluminium foil has a shiny side and a matte side. The shiny side is produced when the aluminium is rolled during the final pass. It is difficult to produce rollers with a gap fine enough to cope with the foil gauge, therefore, for the final pass, two sheets are rolled at the same time, doubling the thickness of the gauge at entry to the rollers. When the sheets are later separated, the inside surface is dull, and the outside surface is shiny. This difference in the finish has led to the perception that favouring a side has an effect when cooking. While many believe that the different properties keep heat out when wrapped with the shiny finish facing out, and keep heat in with the shiny finish facing inwards, the actual difference is imperceptible without instrumentation. "

According to Wiki, the purpose of foil is to keep moisture in, not for keeping heat in or out, which makes sense to me.

I'm pretty sure we're talking about reflecting the heat here. Conducting heat would take it away from the food inside.

I've always put the shiny side towards the food to reflect the heat if hot, and outside, for the same reason, if cold. I thought it was obvious, till I saw professionals even doing it the other way round, covering a turkey on a buffet when they noticed that everyone was helping themselves to a salad or starter and not going for the main course first time round. They put the shiny side outwards. I told them off.

Like Imp27 I did wonder. Good to know I wasn't alone... thanks for posting the solution.

Morning everyone , the shiny side should be down as it conducts the heat better.