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Here are some photos I took of some existing guitars' top bracing this weekend. I am sure there are other better ways to do this, but this worked OK or me and I thought I'd pass it on in case it helps. I'm no expert on this with one day's experience.

All these photos were taken in a completely dark room except for a low light source about 15 feet away off to the side of the guitar (providing a small amount of indirect light). The same focal length of 50mm was used for each shot. 50mm is about how the human eye sees things and is therefore called a "normal" lens. The 50mm lens, of course on a tripod, was exactly 5 feet from the face of the guitar and at the same height off the floor as the center seam of the guitar (35" in my room). The lens pointed at the center of bridge of each guitar. All the file sizes are the same and a rule was taped to the butt of each guitar to provide a known scale. The rule is exactly 6 inches long and 1/2" wide and is taped with the 3" mark exactly on the center seam of the top. While this rule could not be used very effectively to measure bracing widths, it could be used to measure the distance between braces, etc. providing reasonable information. If I printed and overlay these photos they could be compared fairly easily.

Note that the bridge outline can be seen clearly with the larger bridge plate under it in most pictures. Using the in-room light in addition to the bulb allowed this to occur. The in-room light provides more information and clearer information than just shooting in a completely dark room with only the in-guitar light. The details of the in-guitar light are in Part 2.

While all the shots are at f3.2, any f stop would work if you can get enough time on the shutter speed. While all the shots were taken at ISO 1600, any ISO would work if you can get enough time on the shutter speed. I used an SLR on manual control. I could make a Point-and-shoot camera work except for the shot of the extended time required for the sunbust Gibson below. I don't think that one would be possible.

I left the bridge pins out to provide the lighted reference point on the photos. I had to include the bridge pins on the Gibson picture due to the extended shutter time causing the light to burn through and obscure the bridge from view. This same problem would occur if you do not close the sound hole and block the light in the pictures.

This is a Collings 2004 D2H. It was taken at f3.2 and 1.3 seconds shutter speed, ISO 1600. Basically a Martin 1930's Dread bracing copy according to Collings.


This is a Collings 2000 CJ. It was taken at f3.2 and 1 second shutter speed, ISO 1600. Most people think it is a Gibson copy, but it is not. It has the same exact bracing as the Martin '30s Dread but with the slopped shoulders of the Gibson. Collings does not prefer the Gibson sound.


This is a Gibson 1953 Southern Jumbo with dark sunburst. It was taken at f3.2 and 30 seconds shutter speed, ISO 1600. Yes, it took 30 times more time to get the light through the dark bust compared to a natural finished top. The light never did make it thru the edges. But the in-room light allows a clear picture of what is where.


Here is the same Gibby taken at the same exposure but with no in-room light (only the bulb inside the guitar). This lets you see how the in-room light helps clarify what is going on.


This is a 1999 Taylor 414ce. It was taken at f3.2 and 1.6 seconds shutter speed ISO 1600.


On the next part I'll show you how I rigged the bulb up inside the guitar. Here's the link to Part 2: viewtopic.php?f=10117&t=33659

Way cool!

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"Act your age, not your shoe size" - Prince

This is cool! I just did some similar pictures whilst investigating the magic inside on my Taylor XXX-RS. You did a much more professional job than I did.

My problem was finding a light that was small enough to fit inside the guitar, and bright enough to show through the top.

I ended up taking the hood off of a garage work light, and putting the brightest CFL I could find. It was a bit big and difficult to move around inside the guitar, but it worked for my purpose.

Thanks for posting this!

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Jim Hansen

Jim,
Thanks for the encouragement.

The light I used is the "Mini" size florescence which is shorter than the typical florescence size. It is closer to the regular incandescent bulb size or even slightly shorter. In Part 2 you can see that part of the bulb base is actually sticking outside the sound hole so that it will not touch any part of the guitar and cause any possible heat damage. I tried putting the bulb inside the guitar but the bulb itself becomes a distraction and obscures guitar parts. Having the bulb in the sound-hole eliminates this problem since there is not much to see at the sound hole anyway.

Ed

Thanks Ed,

This is very interesting and a great technique in recording the bracing patterns of the guitar. Gives me another very useful piece of information to be added to my build images and documents.

Much appreciated.

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Michael Lloyd

“I was born to ignorance, yes, and lesser poverties ...
I was born to privilege that I did not see ... I didn’t know it, but my way was paved” – John Gorka