High key!

12 posts
3 weeks ago
Mr_Catz
Photographer
Mr_Catz

I had a photo shoot on Sunday working with an incredibly beautiful model. My aim was to illuminate my white backdrop at f8 (same as my key light) but I just could not get my white backdrop luminous white. At one point I had 2 spotlights as well is a strobe light on my backdrop and it still didn't have enough light to correctly illuminate the backdrop.

I actually gave up and turned to plan B which was to just use a white wall. That worked but I have hotspots, and of course the model has to be close to the wall so no real separation.

As anyone got any idea as to what I did wrong with trying to illuminate my white backdrop?

Posted 3 weeks ago
redbaron
Photographer
redbaron

To get a pure white background you normally light between 1.1/2 and two stops brighter. So if you were shooting at f8 then you needed a reading of f16 on the background not f8. Some foresake the meter and simply use the highlight alert on the camera to tell them it is bright enough.

There seems two obvious causes for you issue. The first is the lights you had for the background were simply not powerful enough to get those two stops. This is about knwoing your gear. I have never had that issue but if I did I would have taken the ISO higher by a stop or so so that I would then need less power on the main light to get f8, giving me relatively to that more power for the back lights.

The other possible cause is you are using Lightroom. For some detestable reason the techies at Adobe decided a while back that they had a much better grasp of how our images looked than we do. SO they introduced 'Highlight recovery' Essentially this watches out for blown highlights (ie your background) and recovers them for you. There are no options about this. You cannot turn it off by default. It does not even tell you what it has changed. All you can do is use curves or the highlight slider to get back to where you wanted to be

Posted 3 weeks ago
Mr_Catz
Photographer
Mr_Catz
redbaron

To get a pure white background you normally light between 1.1/2 and two stops brighter. So if you were shooting at f8 then you needed a reading of f16 on the background not f8. Some foresake the meter and simply use the highlight alert on the camera to tell them it is bright enough.

There seems two obvious causes for you issue. The first is the lights you had for the background were simply not powerful enough to get those two stops. This is about knwoing your gear. I have never had that issue but if I did I would have taken the ISO higher by a stop or so so that I would then need less power on the main light to get f8, giving me relatively to that more power for the back lights.

The other possible cause is you are using Lightroom. For some detestable reason the techies at Adobe decided a while back that they had a much better grasp of how our images looked than we do. SO they introduced 'Highlight recovery' Essentially this watches out for blown highlights (ie your background) and recovers them for you. There are no options about this. You cannot turn it off by default. It does not even tell you what it has changed. All you can do is use curves or the highlight slider to get back to where you wanted to be

I fear that the lights I was using were not powerful enough for the job.

I knew I was in trouble straightaway because in the test shot the backdrop should have been blinking on my camera. 

Yes I do need to spend more time playing around with my lights, and getting to know what they can and cannot do.

 

Posted 3 weeks ago
Edited by Mr_Catz 3 weeks ago
Mr_Catz
Photographer
Mr_Catz
 
 

 

Posted 3 weeks ago
Edited by Mr_Catz 3 weeks ago
redbaron
Photographer
redbaron

Another point is to make sure that the lights on the background are just that and are not illuminating the subject at all. Otherwise you will never achieve what you are after. Its that old sod the inverse square rule in which every time you double the distance you half the lighting. This is why no matter how close the model is to the background it is always going to be a shade of grey if you rely on the light illuminating the model. Simply because it is getting less light it has to be darker, ie grey if the model is lit correctly. The only way of getting a true white background is to light it completely seperately to the subject and significantly more brightly. If power is limited then sort the background first. So to take your example set up the background lights at full power then adjust your camera settings so 'correct' exposure for the background is f16 (wihich actually gives a mid grey, hence the need for those extra stops) This may need a higher ISO than yo normally shoot but fine. Modern cameras should cope. Then you can set the camera at f8 and sort the light for the subject knowing the wall is blown and knowing that if anything you will need to turn the main light on the model down in power

Posted 3 weeks ago
Edited by redbaron 3 weeks ago
Mr_Catz
Photographer
Mr_Catz
redbaron

Another point is to make sure that the lights on the background are just that and are not illuminating the subject at all. Otherwise you will never achieve what you are after. Its that old sod the inverse square rule in which every time you double the distance you half the lighting. This is why no matter how close the model is to the background it is always going to be a shade of grey if you rely on the light illuminating the model. Simply because it is getting less light it has to be darker, ie grey if the model is lit correctly. The only way of getting a true white background is to light it completely seperately to the subject and significantly more brightly. If power is limited then sort the background first. So to take your example set up the background lights at full power then adjust your camera settings so 'correct' exposure for the background is f16 (wihich actually gives a mid grey, hence the need for those extra stops) This may need a higher ISO than yo normally shoot but fine. Modern cameras should cope. Then you can set the camera at f8 and sort the light for the subject knowing the wall is blown and knowing that if anything you will need to turn the main light on the model down in power

I did have separate lights on the backdrop. And I knew that I model would need to be far enough away from the backdrop so as not to be affected by the light from it.

So yes my 1st attempt involved trying to light the backdrop separately....... my conclusion is that my lights must not have had enough power to do the job properly.

It was very frustrating for me having researched the subject for many weeks. I even got the appropriate sunglasses for the model. I did intend to get some red helium balloons, but unfortunately they were not delivered on time.

https://www.purestorm.com/image/1595482

Posted 3 weeks ago
Two_stops
Photographer
Two_stops

If you want to whiten the background in that particular image, you could mask out the model in photoshop and use a curves layer on the background. Ok for one shot but a pain if you have to do a complete set.

Posted 3 weeks ago
Mr_Catz
Photographer
Mr_Catz
Two_stops

If you want to whiten the background in that particular image, you could mask out the model in photoshop and use a curves layer on the background. Ok for one shot but a pain if you have to do a complete set.

 

Unfortunately I use Corel paint shop pro X8. I think on this editing software I have to do to the entire picture, and then go over the model to undo the effect on her.

 

Posted 3 weeks ago
blancho
Photographer
blancho

I dont think the power of the lights will have been the issue, it will have been the ratios used between lights and camera

 

Generally to get a background completely white all over without flare (as red baron said) preferably set up two lights at a height half as tall as your subject (or height of your frame) facing at a 45 deg angle to the centre of the background, normally about about 2 or 3 metres away. If you only have one light then it will have to go in the centre probably above the subject shooting 45 deg downwards but this may not be enough to get an even spread of light. The subject will also have to be far enough away from the background so as to not get flare or a white rim around them, normally 3 metres or more. 

 

Your image looks like you firstly only have one light on the background and secondly as you said hasnt enough power for what ever reason, either change your aperture eg,  f16 to f8 and  reduce the power of the main light, or change your iso 100 to 400 and then reduce the power of the main light. 

 

final check make sure your shutter speed isnt to high to sync with your flashes 

Posted 3 weeks ago
1
Mr_Catz
Mr_Catz
Photographer
Mr_Catz

I was going by this video tutorial - https://www.youtube.com/watch?v=tFF2dOXyNuM&t=11s

The 1st thing that I noticed was that his ISO was 200, whereas mine was only 100. I obviously didn't pay enother attention. 

Posted 3 weeks ago
blancho
Photographer
blancho

Its not about the iso your on its about the ratios between the different elements, 

however if the shot you posted was just one light directly behind her head youve done something worng to get such an uneven background, maybe the shutter speed was to high? as well as the light being underexposed

Posted 3 weeks ago
Mr_Catz
Photographer
Mr_Catz
blancho

Its not about the iso your on its about the ratios between the different elements, 

however if the shot you posted was just one light directly behind her head youve done something worng to get such an uneven background, maybe the shutter speed was to high? as well as the light being underexposed

It may not be entirely about the ISO but that did not help.

On the shot I have posted there is no light at all behind the model. That was my plan B – two strobe lights with soft boxes only.

Posted 3 weeks ago
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