Evenly Lighting a reflective upturned bowl

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ghoti

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Is there any trick to lighting a highly polished wooden bowl (upturned) and avoid an ugly, globular, specular highlight?

With my limited knowledge I'm stumped. It seems to me that the convex nature of the surface makes any light source tiny compared to the bowl's "field of view" (if you see what I mean).

Ideally I'd want to produce evenly bright lighting to the front of the bowl, just off centre, which falls off evenly to either side. But I can't seem to avoid a big, blown, spot of light.
 
ghoti said:
Is there any trick to lighting a highly polished wooden bowl (upturned) and avoid an ugly, globular, specular highlight?

With my limited knowledge I'm stumped. It seems to me that the convex nature of the surface makes any light source tiny compared to the bowl's "field of view" (if you see what I mean).

Ideally I'd want to produce evenly bright lighting to the front of the bowl, just off centre, which falls off evenly to either side. But I can't seem to avoid a big, blown, spot of light.
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Very large light source (softbox) very close to the bowl with a lower power setting. But because you want to front light it I'm guessing it would be in the way of taking the picture? And you probably don't have a light source large enough to have it further away?

If you are using umbrellas, use a bounce instead of shoot thru. It will have less of a hot center and more wrap, but it might be hard to get it close enough. So, in this situation it might be a wash, or not enough help.

You could try lighting the wall behind you, with everything set up close to the wall, if that's possible. Using a bare light source will create a "hot spot" on the wall and that will be your catchlight. If you diffuse the light/light more of the wall you will have less of a catchlight. You'll also have to watch out for your own shadow. This will add considerable light to the ambient so you might not be able to drop the BG out. And depending on other factors (room size etc) the lighting ratio could wind up too flat. You could add flags the help prevent ambient from hitting areas you don't want, or to prevent the wall from throwing it back out in all directions (basically barn doors for the wall). Basically, what I'm talking about is just backwards bounce, but with a little more control.

Obviously, the easiest way is to have the right tools in the first place... I'm thinking for the light to be 3-4 ft away (so you can shoot around it) you would need a softbox about 5ft, and quite possibly larger.
 
Phil V said:
This should help.
Click to expand...
Right answer.

Very large light source (softbox) very close to the bowl with a lower power setting. But because you want to front light it I'm guessing it would be in the way of taking the picture? And you probably don't have a light source large enough to have it further away?
Click to expand...
Not exactly the wrong answer, but you wouldn't front light it, you would top light it as per the link to my article above, but with a couple of small changes.
1. You will need to experiment, but probably the overhead softbox would need to be square rather than tilting forwards,
2. put a small mask on the softbox directly above the subject, so that the sides get the quality of lighting you want and the bottom (top in effect) gets less light. Again, you will need to experiment re size, and you may want to achieve a subtle effect by using a piece of ND gel rather than a piece of solid blackwrap or card.

It seems to me that the convex nature of the surface makes any light source tiny compared to the bowl's "field of view"
Click to expand...
Yes, that's the problem with convex surfaces, there is no 100% answer, you just have to use the biggest softbox you can, and get it so close that it is only just out of shot.

If you don't have a softbox of suitable size then a 8' x 4' piece of polystyrene insulating material, suspended above, will do the job - just have it as close as you can whilst lighting it evenly by light bounced off of it with as many flash heads as you can.

Using a white ceiling as the bounce source with do the same job in theory, but you would need to raise the subject up a long way, for it to be close enough.
 
Ah yes, I was thinking centered and a sphere, not 1/2 a sphere. If the light were ~ 45* forward (or potion of), then the catch-light should be "centered."

It may also be worth noting that camera angle/position also affects where the catchlight is. It "follows" the camera position. If you want it lower, then a lower angle will help put it there. This also affects composition, more significantly in most cases.
 
sk66 said:
Ah yes, I was thinking centered and a sphere, not 1/2 a sphere. If the light were ~ 45* forward (or potion of), then the catch-light should be "centered."

It may also be worth noting that camera angle/position also affects where the catchlight is. It "follows" the camera position. If you want it lower, then a lower angle will help put it there. This also affects composition, more significantly in most cases.
Click to expand...

Correct. Which is why camera position needs to be locked in before the lighting is arranged
 
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