Reflections from oil paintings

[BigTam]

I often take pictures of altar paintings in churches. Depending on the weather, time of day and the position and size of the church windows, there are heavy reflections from the glossy, uneven surface.

Sometimes a step or two left or right reduces or eliminates them, but not always.

Would a pol filter help here?

 

[veereshai]

BigTam,

A similar problem has been beautifully addressed with an innovative approach in the book "Light Science & Magic". The basic idea is to work with family of angles (light) and pol filters. You setup two flashes/lights with polarizing gel (?) on them so that the light produced is actually polarized. Then, use a pol filter on your lens to cut the reflection. A better explanation here:

Light Science and Magic: An Introduction to Photographic Lighting - Steven Biver, Paul Fuqua, Fil Hunter - Google Books

Scroll down a bit and check the "Capitalizing on Diffuse Reflection" section. The light polarizing part comes later.

 

[BigTam]

Veereshai,

I'm sure that's a wonderful solution - it sounds logical - but I'm just a normal visitor, and can't use any lighting or influence the light situation in any way.

 

[veereshai]

Veereshai,

I'm sure that's a wonderful solution - it sounds logical - but I'm just a normal visitor, and can't use any lighting or influence the light situation in any way.

In that case, you may be able to cut some reflections using a pol filter, but I doubt (due to the nature of oil painting) that you'll be able to eliminate all the reflections.

 

[RobWatson]

If you can position yourself to obtain a strongly oblique angle such that reflections are minimized and use the geometry tools in post to "square" the images back up - worked for me in a similar situation. If the space is very restricted and you can get away with the camera on a monopod held way out to get as oblique as possible that might help (not always possible).

Careful observation of the source of the reflection and figuring the time of day that they are minimized could also work if the schedule permits.

You can always try a polarizer (try both linear and circular to see if one works better) but I suspect the reflections will not be polarized at all.

The other route would be to become more familiar with the folks in a position to grant special access or get permission to use some lighting. You know, schmooze.

 

[BigTam]

Good tips, Rob, thanks. If I can only get reflection-free at an angle, I use DxO tools to correct the geometric distortion, as far as possible.

But sadly, there are often columns or other obstructions; or the angle is so extreme that the results are necessarily unsatisfactory.

Schedule changes, or waiting for a cloudy day, is sometimes possible. And we have learned to schmooze to get permission to unfold altar side-pieces or even take photographs at all!

The photos are just for our own private study, and as documentation and memory-joggers. No requirement for publishing or professional quality.

But I naturally want to take the best shots I can

I'll get a polarizer, then, and try it out.

 

[RobWatson]

Not sure if you have time but taking multiple photos at different days or times (which all have slightly different reflections) then "stacking" the images using a median combine or some other type of selective tool will result in a combined image with no reflections!

For example in astrophotography or long exposure CCD there are shooting stars or airplanes/satelite or cosmic ray events that appear in a single frame or in multiple frames but at physically different locations. When the images are combined using a median or similar method the common items/features in each frame are retained and the single frame events are eliminated. Tricky part is making good alignment and registration of the multiple images. There are many software packages that can do this.

This way even if a few frames have reflections but they are at different locations they can similarly be eliminated. Even a few minutes difference can result in significant changes in the reflections - especially true if a slight repositioning of ones view point has large changes on the reflections. If so then even taking multiple images from a few slightly changed positions (a few feet left/right/up/down) may give a decent data set to work with.

 

[slothead]

Ron,
I would still try the CPL approach and hope for the best in terms of available light or a flash if allowed.

 

[BigTam]

Rob, another good idea! Definitely worth a try.

Slothead, yes, I'll try a CPL for my O45. Maybe use step-up rings, so I can use it on the O17 and 75 too.

 

[BigTam]

Rob, the more I think about it, the better your stacking suggestion sounds. The surface of these altarpieces is very uneven, so even a small movement left or right produces a different set of reflections.

Any advice on which programs I might try?

 

[RobWatson]

Rob, the more I think about it, the better your stacking suggestion sounds. The surface of these altarpieces is very uneven, so even a small movement left or right produces a different set of reflections.

Any advice on which programs I might try?

IRIS is amazingly powerful and fully featured but geared directly at astrophotography so many LR or aperture type tools are totally absent. Oh yeah, also totally free!

MaximDl is a bit pricy and also geared towards astro works. The alignment and stacking tools are very good. They do have a 30 fully functional free trial. This is one of my "go to" tools for alignment and stacking. The basic download version at $199 is all you will need.

AIP4WIN is another astro package (getting a trend?) that is ~$100 but the tools are clunky.

I bet some one with more experience with photoshop can point to tools for stacking that are either already there or maybe a plugin. Here is a nice page showing some explicit work in some other free ware and photoshop.

If you have a image set that you would like me to work on just to show you what is possible I'm happy to help (I have all the tools above and more).

A little read on some of the stacking/combining methods might be of interest.


The "better" packages will be able to combine the geometric, alignment, registration and stacking into a single package or possibly even a single tool. I like free tools so I have lots and each have one or more tools I like best so may end up using 3-5 packages for one project!

 

[rnagoda]

Can you use a tripod? Sorry if I missed an indication of that earlier, but if you are able to, then just use a very long exposure time and no flash at all, maybe?

Whatever lighting problem your flash is solving will also be solved by 4 or 8 seconds of open shutter, and there's nothing to reflect off the subject.

 

[BigTam]

Magoda, the reflections are from the light from the church windows and/or lighting fixtures. I don't use flash.

So a long exposure wouldn't help.

 

[Savas K]

How about pop-up diffusers or gobos?

 

[rnagoda]

Magoda, the reflections are from the light from the church windows and/or lighting fixtures. I don't use flash.

So a long exposure wouldn't help.

Damn. Now I suppose I'm expected to read through the actual posts in a thread?

Sorry man - trying to surf/work doesn't always work out!

 

[Crdome]

I have photo documented corporate, private, and public art collections for decades. Often the art is glazed or highly polished and the ambient light is a night mare from a plethora of ceiling lights and windows.

Using ambient light, there is almost always a reflection-less angle without obstructions ...from the floor up, or down from above. For me a long zoom is essential. position. That position may be maybe from standing on a file cabinet a a hundred feet away. At that distance the angle may be a straight 90 to acute. Traditionally when I shoot corporate collection my camera of choice has been the Panasonic FZxx. I started with FZ-3 documenting cemeteries. It's lens was an amazing F2.8 thru entire 430mm full zoom). I've progressed through the FZ8, FZ18, and currently the FZ60.

If a flash is required I use the built-in, diffusing the light by shooting through a small piece of paper napkin or tissue taped over the head.

In my capacity, I always have the dimensions provided. For you, shoot a straight on, no matter how bad, to provide its relative dimensions for PP.

-Chrome

 

[BigTam]

Chrome, many thanks for sharing your valuable experience. I do try different positions and angles, maybe I should be bolder in my attempts! I take it, since you didn't mention it, that a CPL filter won't help?

My wife organizes exkursions for those interested in early christian art, and I take photos so that when she is preparing her talks, she can check on details.

On our visits to churches to prepare for such exkursions, we usually have limited time at each venue.

So all the helpful suggestions above have given me more ideas about how to make the best of a difficult situation.

I also document paintings for an art class my wife teaches, but there I can usually position the painting as I please, use a tripod and have control over the light, so no problems. I use DxO's trapeze tool to restore correct perspective, fairly simple.

Again, many thanks for all the help: this really is an amazingly civilized forum.