Techniques to Achieving the Best Lighting in this Situation

[Bradenh]

I am having some trouble figuring out the best lighting: the subject is placed in a corner between a white wall and a large window. This is for a design project (I'm in art school studying photography) so the set up is awkward and concrete.
So far I am using an umbrella and a flash to bounce the light towards the side of the subject facing away from the window to get equal light, but this causes a shadow directly down the front of the face. To get the exposure right on the background means that the subject is over exposed. I might have access to a reflector but I am assuming I will not have one when I take the photos.
I am wanting to have even light over the subject/s while keeping some detail in the background which is white tulle and fabric.
I am not new to photography, but rather new to using flash (especially using an umbrella) with portraiture— I appreciate any tips or ideas to achieving the best lighting in this setup.
I created a diagram with The Online Lighting Diagram to give you a better idea of what I am explaining. I anmself taught up until now so I may seem pretty niave so bare with me.

 

[runnah]

If the light from the flash is too hot turn it down or pull back the stand. Do you have a sample photo?

 

[tirediron]

Can you have the subject turn so that they're getting full sun from the window on their face?

 

[Big Mike]

Might be easier if you skip the flash and just try to use the window light and a reflector.

If you are going to use flash, the key to balancing it with your ambient light, is to know that your shutter speed affects the ambient light, but not the flash exposure (as long as you keep the speed under the max sync speed of the camera).
You can also adjust the power/position of the light, which will affect the exposure from the flash, but not the ambient.

So using those two variable to independently adjust the ambient and/or the flash exposure, you should be able to come to a balance that will work for you.

 

[amolitor]

What is the "background" here? I am seeing both a window and a wall in the background, and a backlit subject, all of which are gonna be problems.

I assume there's light coming through the window? It's not night-time?

If so, I would dump the flash and use a reflector to push the ambient light from the window onto the front of the person. Put the reflector directly in front of the model, perhaps just above the camera. Not so high that you lose the eyes in the shadows cast from brow/forehead. You're backlit, so you're just looking to fill to avoid silhouetting.

 

[Derrel]

Your diagram has some issues...the reflector placed as it is shown will not reflect very much of any light...incorrect reflector angle is often an issue for the self-taught.

Anyway...you need to get 1) the ambient light exposure right, for the tulle fabric and window. Think ISO 100 at 1/125 second at f/8. As a starting point. Whatever the daylight is like will vary the ambient exposure, so first off, figure out the RIGHT exposure for the window and the tulle fabric. You MUST keep the shutter speed and the f/stop and the ISO at one level, for the natural window light, and then place/position the umbrella flash at the right distance to provide some light on the "off" side.

First off: the closer to the window, the more-rapid the person's face will suffer lighting fall-off and the shadowed side of the subject's face will drop into shadow. At 2 feet from the window, the fall-off on the shadow side will be VERY dramatic....moving the person another 2 feet from the window will make the light more-even.

The goal here is to 1) nail the right exposure for the window and tulle fabric: use the camera's light meter and test shots to determine the right exposure for the window and tulle fabric. Remember--you can not exceed the X-sync speed of your camera.
2) position the person at a good distance from the window and then
3) bring in some fill-flash from the right hand side, to make the lighting look good.

 

[Designer]

to get equal light,

Wondering why you want this. I think this may be your first wrong turn.

 

[tirediron]

to get equal light,

Wondering why you want this. I think this may be your first wrong turn.

I took this to be part of the exercise; "Produce flat lighting using ambient and strobed sources"?