Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

If you are responding to my question, then the answer has already been provided by E.L.. Shapiro thoroughly and in great detail. It is the ONLY way to do what you want to do. Polarize the light sources, use a polarizing filter on the lens, place the lights at 45° to the surface of the artwork and the camera in between the axes of the two lights, and use the sharpest aperture of a normal to slightly longer than normal lens.

I would add that you don't want a fast optic - lenses that are F2 and faster have all kinds of faults that can make life difficult, the least of which is focus shift as you stop it down.

BTW - using the "Quote Reply" option instead of the "Reply" option will quote the text, and let everyone see who you are responding to.

lowkick Loc: Connecticut

Years ago, pre-digital, I had to copy some photos out of a glossy paper coffee table book. I ended up buying a sheet of non-glare glass large enough to cover the book's pages. It worked quite well. It was the easy way out, but I had control over the subjects. I could place then wherever I wanted and light them as needed.
Depending on what you are shooting, and where, that might not be a good solution for you. But if you have control over the subject, it is probably the easiest way to get the job done.

Mustang1

I reiterate.

burkphoto Loc: High Point, NC

Yes, I've done it for years. One method involves polarizing the light sources and then using a polarizer filter on the lens to cancel out the glare.

One trick I've used involved that, plus a black shroud over the area above the camera, and a black baffle mounted on the lens filter holder to hide the camera.

If not doing that, be sure you are illuminating the art with two LARGE, highly diffused light sources, at 37.5 to 45 degrees from the frame or copy stand baseboard axis. Both should be the same intensity, and they should be feathered to achieve very even exposure across the entire surface of the art.

The quality of the light determines how any three-dimensional surface details will be reproduced. Highly specular (small) light sources may "speckle" the image where it has paint daubs, brush stippling, silk photo paper texture, etc. Increasing the size of the light sources relative to the size of the subject art can make the entire art the same brightness, diminishing shadows and speckles almost completely.

Many resources are available to guide you in choosing lights, filters, copy stands, vacuum backs, and techniques. Ask a sales associate at a really good camera store for some guidance. Copy work is an art form itself!

Timmers Loc: San Antonio Texas.

The professional method is to mount the glass covered or other object to a fixed surface (hang it on a wall). Using a photo stand (kind used for holding lights) close to the camera on a fix stand (tripod) that is level and centered to give a flat view of the framed work. From the stand at the side, hang a matt black cloth with a hole in the cloth to allow the camera lens to view the object but the drape covers all other items in the room (including the photographer) and close out/off all other light source except those illuminating the art item.

By the by, using two light sources at 30 to 35 degrees (not the usual wisdom of 45 degrees) is also recommended.

DoriguzziPA

Buy a sheet of polarizing filter from B&H
(https://www.bhphotovideo.com/c/product/45130-REG/Rosco_101073001720_Polarizing_7300_Filter.html)
to put over (cut to fit BTW) your two lights at the 45 degree angles. Make sure that you have marked the direction of the polarization on each sheet and that they line up the same for both lights. Then use a 'regular' polarizer on your lens - may take a minor amount of test shots to verify the proper cross alignment that has minimized all the glare. Then shoot.

I have used this method for decades and it is the best!

Timmers Loc: San Antonio Texas.

This nonsense about polarized lighting is the most ill advised of all suggestions. Many art works are made using multiple materials (called mix media), under polarized light there are distinct shifts in the representations of these materials. You get absurdly incorrect results from such lighting. Avoid polarized light when shooting art works.

E.L.. Shapiro Loc: Ottawa, Ontario Canada

There are many ways to simply make a record mage of artwork- you can McIver quick and dirty methods that work some of the time. I.ve shot paintings that were displayed out-of-doors at craft shows, with my cell phone camera so I could show them to my wife. Sure you can shoot it at an angle where someof the reflections are minimized- it will probably be keystoned- whatever? If, however, you need accurate colour rendition, reflection control, high definition for reproduction, or if you are creating a catalogue for actions sales, etc., you gotta do it properly.

Shooting through non-glare glass is NOT the solution. Non-glare glass has a tendency to gray down the image and reduce shadow detail. Even costly so-called conservatory glass, which is sandblasted or etched on one side, can cause problems well. These types of glass do not eliminate or cut through reflection- the dispersion of light on the surface somewhat reduces the mirror-like reflection and makes them less apparent but the desaturation is still there. If the glass is not in close contact with the artwork, it diffuses the image.

Many photographers consider art reproduction, copy and restoration work kinda boring and non-creative. The fact is that it is extremely interesting, presents many technical challenges that need to be resolved and requires precise technique.

Over the years, I have enjoyed doing this work for many reasons. I get to see some incredible works of art- up close and personal! I learned a lot about various painting techniques, such as underpainting, varnishing, pigments, and what happens to different kinds of mediums as they age. All of these can present problems in reproduction and need o to be addressed. I also enjoy working with living and contemporary artists, new talent emerging, as well as the work of the Old Masters, antique pieces, and some absolutely and incredibly beautiful work of painters that were not necessarily well known in their era but have been recently discovered. It's also fascinating what archivists, curators and folks that restore damaged works of art are up to.

Oh- It pays well too!

TRSquared Loc: South Carolina

I did this sort of work for many clients over the years. Some were artists and many were art museums including the Metropolitan, MoMA and the Smithsonian Museums. The first thing to remember with art under glass is that glass is like a weak mirror reflecting anything in front of it. For on-location shooting I took a large black felt drape that I supported behind me. I wore black and my tripod was covered in black.

For lighting I had a two light setup aimed at a 45° angle to the art. The reflection of one light goes straight back to the other light and, unless the photographer uses a lens of short focal length, the lights are not visible. I made sure the light fell only on the art and none on the felt. For the highest contrast saturation in my result, I always had the art against something black or at least very dark and never on white. A room with dark colored walls is also best. My studio was large and painted with flat black paint. I always used the longest focal length lens possible for the size of the art and size of the room.

Some other posts to your query mentioned polarizing material and I used that material over my lights with a polarizer on my lens BUT please know doing so was not a solution to the glass problem. If the light shows in the glass, then even with the polarizing, the lights will be a problem. But polarizing the light falling on the art and having a polarizing filter on the lens, does significantly reduce reflections from the surface of the pigments and paper and allows more saturated colors in your result.

I remember being in one museum photographing when a fellow walked by the workroom door that was open and did a double take. I had some framed art under glass sitting on the easel. He looked at what I was doing and said, "I am a photographer. What you are doing is impossible!" He did not know the tricks. They are all just simple physics.

lamiaceae Loc: San Luis Obispo County, CA

[per your last couple paragraphs] Yes, you get it. I even got to photograph William Blake and J. M. William Turner drawings! Cool you were around for new artists. I have had that happen with musical artists, met and photographed singers and players that are famous today but virtually unknown when I met them.

frangeo Loc: Texas

Big black gobo over and around the entire case. Light from both sides. Tricky but it works.

E.L.. Shapiro Loc: Ottawa, Ontario Canada

Don't know about that! Gotta disagree!

I have photographed oil paintings of all ages, watercolours, acrylics, poster colours, crayon drawings, etchings, pen and ink renditions, silverpoint works, silkscreen, pastels, and charcoal. I worked for an artist who paints on glass and various plastics. I am familiar with mixed media. I have never had an issue with strange colour shifts or inaccuracies. There are certain plastics that can be problematic in that the stress patterns appear under polarized light and those sites have to be addressed in a different manner.

I've made copies of colour negative and transparency materials and digital media as well with no problems. my clients are art galleries, museums, and archives where I am delag with knowledgable curators, printing houses where art books and expensive prints are made where colour accuracy is closely monitored by experts in the field.

The only time I don't use polarized light in conjunction with a CPL filter is where metallic inks and foils are used in the artwork.

TRSquared Loc: South Carolina

Shapiro speaks from experience and my experience is identical to his. The benefit of using polarizers is due to the physics of the reflection of light from surfaces. The simple version is this. When light strikes a surface with paint, chalk, etc. there are two components to the reflected light. One component is from the very top surface. Because it is from the top surface it carries little or no color information from the art. It is specular reflection like that from a mirror. That light is polarized in the same plane as the incoming light because it is from the electrons in the surface that vibrate with the incoming rays. If the incoming light has random planes of polarization, then the surface reflection will also be that way. But if the income light is polarized in one plane, then the top surface reflection will be likewise.

The other component of reflected light is light that penetrates the a surface short way and interacts with the atoms of the material. Because of the interaction with multiple atoms of the paint, chalk, etc. it becomes randomly polarized even if the incoming light had a single plane of polarization. Some of this light is absorbed by the pigments and some leaves the material carrying the color information.

By placing polarizing material over the light source with a vertical axis of polarization, we cause all of the top surface reflections to be polarized in the same plane. Adjusting the polarizer on the the camera lens to be perpendicular to this plane removes just about all of that light permitting the light carrying the color information to be the only light that enters the camera. This is the same reason why many nature photographers use a polarizer. It is not so much to just darken the sky, but to drastically improve color saturation in vegetation and other elements of of the landscape. It works on snakes too! The physics is similar but not identical to what is done with art because the incoming light is not polarized but using a polarizer does work to improve saturation.

If you wish to do a professional job photographing art, go back to Shapiro's original detailed post on this subject. There is nothing else I can think of that you will need that is not explained therein.

E.L.. Shapiro Loc: Ottawa, Ontario Canada

Thanks for the explanation- I haven't reviewed the physics of polarization since my school days when the professors outlined the underlying theory. My "instructions" are simply nuts and bolts" how to stuff based on my experience and courses I have taken.

There are, however, a few instances when photographing artwork where a decision needs to be made whether or no to use the double polarization system that I recommend in most cases.

There are some rare cases where the reflection from the surface of some paintings should not be eliminated simply because they add to the authenticity of the reproduction. It could be a component of the varnish or a surface texture the needs to be revealed in the copy. In paintings that are NOT only 2-dimensional but somewhat 3-dimensional such as bas-relief and pallet knife paintings. This is where interpretive copy-lighting techniques are applied. One light is used, at around 45-degrees and FEATHERED to skim the surface, same as you would in order to render the surface of a terrycloth towel or a piece of barn wood or tree bark. Oftentimes, however, the double polarization technique better reproduces the depth of underpainting techniques.

Another issue of double or cross-polarization methods is that it increases colour saturation and contrast as a result of eliminating reflections that tend to dilute those attributes. In order to control those effects so that the reproduction looks more authentic, is to control the contrast and saturation. In the film days, I would routinely overexpose and underdevelop transparency materials-1 full f/stop and pull-process accordingly. This would ensure adequate shadow detail and produce more realistic contrast and colour saturation while compressing the range for good lithographic reproduction. Nowadays, in digital imaging, it is easy enough to control contrast and saturation in post-processing so you can use full polarization techniques and still retain a natural and authentic reproduction quality.

In some very old paintings, the surface becomes cracked or checked. Show the surface cracks may be important to retain the mood or impression of the work and may also be significant for those who are authenticating or studying the age of the work. Sometimes the interpretative one-light method can be applied, in some cases, the cracks will show well enough with the regular double polarization method, and occasionally it may be necessary to apply a lesser degree of polarization when rotating the filter below the point of maximum polarization.

I realize that this thread was mainly concerned with glass-covered artwork but similar problems also arise with many kinds of surfaces having to do with varnishes, the glossy nature of some mediums, and otere interferences that may appear on older works of art.

Bibliography: It's unfortunate that the Kodad data book "Copying and Duplicating-Photographic and Digital Imaging Techniques" has been out of print since the late 90s. Anyone interested in copy and restoration work shod try to obtain a copy. It contains a wealth of knowledge. I took a course with one of the contributing authors and many of his techniques are outlined in the book.

Scruples Loc: Brooklyn, New York

This makeshift gear was for store windows during Christmas time. If I had such a set up, I would contact the curator of the museum in advance, explain what I am doing and what if to know if I could photograph before or after hours. It is highly unlikely and they would probably try to sell me stock work. I’ll take them but be disgruntled about it. Oh, I leave my business card just in case they need a new photographer.