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I am trying to take a good picture of an old oil painting (a portrait) in a gold-painted wooden frame (no glass), and I’m having some trouble avoiding glare on the frame.

My basic setup is this:

  • painting is mounted on the wall, about 2m from the camera (mounted on tripod)
  • the room is completely darkened with no ambient light
  • two LED lights (5500K) are positioned about 2.5m from the painting, at roughly 30–40° angles, both shining through a shoot-through umbrella to diffuse the light
  • camera is set to F11 aperture and exposure times between 15 and 30 seconds

(It’s worth noting that, while I do have some basic gear, I am a hobby photographer, and I don’t have access to a proper studio or real, professional-grade gear like dedicated softboxes or diffusion screens. I have the two LED lights and a few umbrellas – two shoot-through, one bounce – but that’s more or less it.)

When I take the picture, the actual painting itself is fine – there is very little glare, despite the oil being very reflective and very black, making glare very obvious.

The wooden frame, however, is very three-dimensional and curvy, and the paint used on it seems to have a fairly high refractory index, so whatever I do, however I position and turn the lights, I get terrible glare on either side of the painting where the curved bits reflect the light straight back at the camera lens.

This wouldn’t be an issue if I could just crop out the frame, but unfortunately the frame itself is essential and must be part of the final image.

I’ve tried fiddling around with shooting several exposures, combining them to an HDR and brushing in adjustments to reduce highlights and whites, but that just ends up making the wood look like dark mahogany with bright white spots – the ‘dark’ parts of the wood are apparently bright enough that they count as highlights, and the glary parts are just shot out and unsalvageable.

Is there some way to avoid, or at least minimise, this wooden glare while still maintaining the frame well-lit?

 

Here is an example of a shot with the obvious glare on the wood:

Portrait with glare on wooden frame

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  • I don't know enough about this to provide an actual answer - maybe someone else can pick it up & run with it, or let me know why it wouldn't work - but I've seen photographers using two sets of polarising filters for really bad reflections; one on the camera, as expected, but others on the lighting itself - so you can tune one against the other. I've seen it done, in advertising shots for beer/wine bottles, but I've never done it, so that's the best I can do, sorry. – Tetsujin May 19 '20 at 14:02
  • @Tetsujin That sounds interesting, but complex! Unfortunately, I only have one polarising filter (and it doesn’t fit the lens I’m shooting with here), so I don’t think it’s a possible solution for me, but I can see how it might work (I think). – Janus Bahs Jacquet May 19 '20 at 14:03
  • The filters on the lights looked just like colour gels, so might not be all that expensive. For the camera, I guess if it's too small for the lens you're stuck… if it's too big, there's always camera tape ;) Amazon said £6 for 100x100mm polarising gel hmm, that's tiny, 100 bucks for something softbox sized :\ – Tetsujin May 19 '20 at 14:05
  • The glare being mostly on the vertical parts of the frame, using a single polarizer on the lens could have some effect. Easy enough to test. – xenoid May 19 '20 at 17:31
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The only way, I would try, is to use a soft light source, that is as large as possible and can be placed at a longer distance.

The problem that you will encounter is, that you want soft light to minimize reflection (aka glare) on the frame. This is achieved via using a diffused relatively large light with even light distribution.

Then you want to control the specularity itself. This can be achieved by exploiting the inverse square law to flatten the lights, cuasing less contrast. The further you place the light away, the more the light acts as ambient light. However, the drawback is, that the further the light is away, the smaller it is related to the subject.

So, you could try a really large light in a softbox (or more affordable a white reflex umbrella with diffusion) and place it in a fashion you just don't get the reflection of the light in the painting.

However, there are limits to this due to the reflective paint on the frame.

Another way, but not applicable on artworks, would be to apply a matte texture of the glaring parts to diffuse the reflection. But you cannot use matte spray on an artwork.

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  • Yeah, if I had access to a softbox, I would definitely have tried that as well. Unfortunately, the two LEDs are the only movable light I have available (edited question to include this information). I do have one white bounce umbrella (though not two), but that would diffuse the light less than white shoot-through umbrellas, wouldn’t it? And yes, I think the owner of the painting (who happens to also be my boss) would sadly be somewhat less than gruntled if I matte-sprayed his portrait frame. – Janus Bahs Jacquet May 19 '20 at 14:55
  • In lieu of a really large soft light source, multiple smaller (but still soft and diffuse) light sources from different directions can provide a reasonable first-order approximation... – twalberg May 19 '20 at 15:05
  • @twalberg Good point. – Kai Mattern May 19 '20 at 20:44
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The left side of the frame seems quite acceptable, I presume it's the right side that's the issue.

Now that you've got everything other than that right side of the frame good, move, add or remove lights until you get a good image of the right side of the frame, then composite the two together taking the good from each of the images.

Remember that when you look at the picture with the naked eye under ambient lighting, you're likely to get some glare off of different parts of the frame as you move your head around.

If it's critical that you eliminate all glare from all parts of the frame, then I'd suggest that compositing the final image is going to be the only way you can do it. Once you're happy with the lighting of the painting itself (and it seems you are), focus on each individual side of the frame, adjusting not just lighting, but exposure as well (if necessary) until you've managed to eliminate all glare on that side of the frame. Depending on how fiddly it is, you may have to have a "top-half, left side" image and a "bottom-half, left side" image and combine the two of them to get a satisfactory "left side" image.

Since this appears to be an old painting in an old frame, it's likely that the frame was hand carved. Techniques existed to make the coves with machines, but the ornate work towards the outside of the frame would have likely been done by hand. Even machine worked curves (if this was from the 1800's to early 1900's) would likely have not been perfectly smooth, thus there might be slightly different angles present that aren't obvious to the naked eye, but are being picked up by the camera under studio lighting.

Shooting RAW will, of course, be necessary, especially if you have to adjust exposure to eliminate reflections. You'll need to adjust the outcome of each exposure to balance the final output and RAW will give you the extra room you may need to do so.

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  • Ideally, I’d like to get rid of the glare on the left side too. I suppose I could take three or four shots with different lighting and stitch them together right at the painting/frame edge… if I can get that to work well. – Janus Bahs Jacquet May 20 '20 at 11:46
  • @JanusBahsJacquet please see the additional thoughts I've added – FreeMan May 20 '20 at 12:02
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The problem:

enter image description here

Some options:

I. Who says the lights should be on "both sides" of the frame?

How about putting one light on the left and above the painting, and the other on the right and below the painting?

This way the reflection will move to the corners of the frame.

enter image description here

But as you commented, it probably did not look better. This solution needs a lot of space.


II. Option 2, a large light source.

You could put a large and slim softbox on both sides, more or less the size of the painting itself.

enter image description here


III. Simpulate one big light using multiple exposures.

You can simulate a large strip box taking several shots, moving up and down the umbrellas, and compositing them later. I would use a remote trigger so I do not touch the camera at all. There are some generic ones really cheap.

enter image description here

This is probably the cheapest solution for this case. Of course, if you have many paintings to photograph, two softboxes or two strip light will be a good investment.


IV. DIY softbox

A DIY solution is to use a roll of vegetal paper as a softbox. The paper must be diffusive enough.

You can put a tube between two light stands and hang the paper. There are kits to hold backgrounds that can be used.

You could even use PVC pipes to make a frame. I love PVC pipes. Just make a sturdy structure. You do not want it to fall on the painting.

I must say that diffusion will be limited because on large softboxes you have a hot spot. You could double the layers to double diffuse the light, but reducing the power.

V. Bounce the light

You can also bounce the lights on white walls or foamboards.

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  • I did try that – the glare did move, but let’s just say it didn’t exactly look better… – Janus Bahs Jacquet May 20 '20 at 11:44
  • I edited the post. – Rafael May 20 '20 at 12:14
  • Maybe I'm missing something, but all of your suggestions seem to increase the amount of reflection. The OP is looking to eliminate the reflections entirely. – FreeMan May 20 '20 at 16:44
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Have you considered using cross-polarisation with a flash? You use a polarizer sheet/gel on the flash and a polarizer on the camera in the orientation blocking direct reflections of the polarized light from the flash.

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Polarize your light sources and use a CPL on the camera to filter it out.

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Try to create soft light as much as possible. What you want is more diffused light. Instead of using umbrella to diffuse light use white curtain which mostly used as backdrop.

enter image description here

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