How do I take this backlit shot? - is it even possible?

I took some portraits of a model,for her portfolio.
They were done in the lounge of her rented home (so can't change much).
The problem is this room has very white, see through opaque voile curtains. Virtually no sunlight is stopped. To do the shots, I set my 7D to 1/250 and ISO 160 and as per flash meter aperture of F13 using a 70mm setting on the 70-300L.
The Bowens were set to 3.9 out of 5 power levels. Main being a 500R (watts) and the fill being a 250R (watts). They all came out perfectly, maybe 1/3 to max 1/2 a stop over exposed, but as I like darkish photos no problem - in post easily made perfect. She really liked them.
The problem:-
She has seen some shots I took of another model, where the white room was totally blacked out, no natural light at all, and both the 500 and 250 watt studio lights were fired, angled from either side, from behind the model and placed just out of sight.

The idea was to create a halo effect, where the model was lit from behind and the only lighting to the (front ) of the model was the light that bounced off the white walls and ceiling.
My problem is the new model, has seen this backlit image image wants some and is willing to pay me to go back and do this for her. The original backlit shot worked very well IMO and obviously the new model agrees enough to get her wallet out.

So you see my problem, the backlit shot was done in a totally dark room, even using the modelling lamp facility within the studio flashes to be able to focus.

The new room is pretty bright and being a seaside town, if its a sunny day then that room will be pretty light.

So the question is will 1/250 ss at ISO 160 and say F13 cut out the natural light enough to create a halo effect and turn the front of her very dark.
I can't use HSS, as bowens doesnt support that i.e. make it so fast that the natural ambient light wont show.
Or could I go down to F 22 ? Or even F32

Any advise welcome

Sorry dont have the backlit shot on this iPad4, and its not the same place or settings anyway - so its really a technical guess or down to one's experience.

If only I had known at the time I could have put the flashes behind her, taken a shot and if it didn't work posted the picture for people to try and give me corrective advise.

Naturally I don't want to go back and fail and look a total prat!

Sorry to state the obvious, but can't you do the shoot in the evening, after the sun has set?

Temporarily put up some black curtains? Shouldn't be *too* hard unless the windows are huge..

Just dim the ambient light...

Either method above will do

i keep cardboard and poster board/foam core around for flagging windows.

obviously the foam core is much more professional looking, you can find it in any craft store.

sandpiper wrote in post #15848253
Sorry to state the obvious, but can't you do the shoot in the evening, after the sun has set?

Sadly its really too far away!

jackerin wrote in post #15848306
Temporarily put up some black curtains? Shouldn't be *too* hard unless the windows are huge..

Unfortunately they are ceiling to floor - and patio doors, massive, thought of that. Maybe 6 king size sheets.

You could try HDR. But HDR with people doesn't work well unless you REALLY know what you're doing with the software you're doing the HDR with. This way your windows and you subject will be perfectly lit. You might be able to do a 2 shot HDR. One with the window exposed correctly and the other with your model exposed correctly. Could be tricky though if you're not familiar with HDR.

CameraMan wrote in post #15848454
You could try HDR. But HDR with people doesn't work well unless you REALLY know what you're doing with the software you're doing the HDR with. This way your windows and you subject will be perfectly lit. You might be able to do a 2 shot HDR. One with the window exposed correctly and the other with your model exposed correctly. Could be tricky though if you're not familiar with HDR.

You have misunderstood the situation, the window won't even be in the shot. HDR won't be necessary as the OP is using studio lighting to give the result they want, they just need to kill the ambient coming in from outside.

Oh, then if the window isn't going to be in the shot then you can easily throw a blanket over it. Sometimes I'll bring a stand that I made with PVC and throw a blanket over that to help block any extra light that you don't want/need.

It seems the only two solutions are to shoot after dark, or block the light coming in during the day. I really cannot see any other way to deal with the ambient light.

If shooting after dark is out of the question, I would simply explain to the model that the shot she wants requires that minimal sun is coming in at the windows and that if she wants you to do it, she needs to either hang something to cover the window (before you get there) or arrange another location where there are better curtains, such as at a friends house. That could also potentially offer another benefit, if the friend sees the shoot and also decides she would like to give modelling a go. You could get another paid gig while you are there, and already have the lights set up.

Maybe it's due to my location and transportation availabilities... but I don't understand how distance (too far away) and time of day (night) are related

Nonetheless, I don't know how much ambient light you were 'seeing' via your camera sensor, but you might not necessarily have to cover ALL of the window(s). I've been in a clients home where they had windows lining one side of their main living area... I was doing some child portraits on one side of the room, and just closed the blinds on that side... other windows were left alone. It doesn't have to be an all-or-nothing thing... but you may have to make compromises.

I have to assume that the 7D can shoot at ISO100... can it reach ISO50 (custom functions)? What about pushing your shutter more? Have you tried to see if banding is noticeable at higher shutter speeds? If so, what about framing your subject so that you crop out said banding?

I can understand that if there is a nice spot in this models home where she'd like to have a photo done then arrangements need to be made to make it more photograph friendly. I have the same situation at my home. We have a nice mantel and fireplace but there is a sliding glass door next to it. I used to cover it with a blanket when we'd do family portraits but last year I invested in some energy saving heavy curtains. This has helped that spot tremendously.

CameraMan wrote in post #15848513
I can understand that if there is a nice spot in this models home where she'd like to have a photo done then arrangements need to be made to make it more photograph friendly. I have the same situation at my home. We have a nice mantel and fireplace but there is a sliding glass door next to it. I used to cover it with a blanket when we'd do family portraits but last year I invested in some energy saving heavy curtains. This has helped that spot tremendously.

Just curious, what direction does this door face?

Have you done natural light shots near the door? What about with a large diffuser (e.g. white sheet) covering it?

I can certainly see where this would be difficult for a family shot, because the falloff would be tough on the other side of the family (opposite the door), but for single portraits, there may be some nice light to be had.

drvnbysound wrote in post #15848501
Maybe it's due to my location and transportation availabilities... but I don't understand how distance (too far away) and time of day (night) are related

I'm the same as you, the distance wouldn't matter to me either. I have been known to do late evening shoots at the other end of the country, finishing after midnight, with a 4 hour drive ahead to get home.

However, we are not all the same. Some people like to always be in bed at a reasonable hour, some have partners that would not be happy with them getting in at a late hour, or they have to be up early for work (postmen etc.). It may be something that we don't think about, but I just accept that the OP has (for them) good reasons for not wanting to do the shoot at 9pm and then get home at whatever time it would mean.

Not everybody has the same freedom to shoot whenever they like, I am lucky in being able to set my own timetable 24/7 and fit work in as I please.