Panoramic Infrared Reflectography for painting documentation

I already blogged on using Gigapan Pro Panoramic head with a modified digital camera for multispectral imaging. This blog is about using the same head with an InGaAs camera for fast Panoramic Infrared Reflectography.

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Multispectral imaging at the highest resolution possible and in the shortest time is a great advantage for documentation of large collections. There are excellent medium and large format cameras on the market which produce large file, but they are expensive. The affordable solution is a panoramic head coupled with a stitching software. A motorized pan head such as the EPIC Pro produced by Gigapan allows to make the process automatic. Any DSLR camera can be used together with a prime telephoto lens.This is how I get multispectral imaging at high resolution. The multispectral images have pixel dimension 12000 x 1000 and have been collected with a modified Nikon D800 – 36 MP – and a 200 mm telephoto lens with a total of 12 stitched shots. Images are uploaded on IIPImage server and visible here

Multispectral imaging of this size and higher can be shared on the internet using IIPImage, an image server system for web-based streamed viewing and zooming of ultra high-resolution images. 

The Gigapan EPIC Pro motorized pan head as said – allows to automatically take the shots sequence since it can trigger a DSLR camera with cables provided for the major camera models. Though, this head can be used in automatic with any imaging device connected to a PC since a USB trigger adapter can be implemented. Gigapan don’t provide this trigger adapter device yet but I know they are working on it or you can make it yourself and they will be happy to tell you how to set it up. Otherwise you can just keep saving your images manually.

Infrared Reflectography mosaicing

Infrared Reflectography mosaicing of 104 InGaAs images. Gigapan makes the shooting process precise and fast while PTGUI takes care of stitching the images.

Panoramic Infrared reflectography is the low cost alternative to high resolution infrared reflectography done with pretty costly systems. I plugged my InGaAs camera  (320×256 pixels) Merlin NIR produced by Indigo Systems to a Gigapan Pro head to produce the Infrared Reflectography image hosted on gigapan.com and on IIPIMAGE. A total of 104 images were shot with a 200 mm telephoto lens and stitched with PTGUI software.

panoramic infrared reflectography

Gigapan Pro can hold a digital SLR camera as well as an InGaAs or a Thermal Camera. It makes stitching more fast and precise.

The video below show the PTGUI stitching procedure. If you consider you get the stitching in 2 minutes and you invested just $200 for the Telephoto lens, $200 for PTGUI and $1000 for Gigapan, it sounds pretty fair. Caveat, in the stitching totally automatic process, software can make some mistakes. But you can correct them adding control points.

Using an automatic trigger, a panoramic head could be used  with any other imaging device such as thermal cameras for detailed thermographic imaging of historical architecture.

 


pigments checker v2 vsPigments Checker is for photographers, conservators and scientists interested in technical documentation of paintingss. It has 54 swatches of historical pigments designed for infrared photography, ultraviolet photography and other technical photographic methods for art examination. Check it out!

Pigments Checker is a collection of 54 swatches of his­tor­i­cal pig­ments that have been applied using gum ara­bic as a binder on a cel­lu­lose and cot­ton water­color paper, acids and lignin free. This paper is not treated with opti­cal bright­en­ers, it’s slightly UV flu­o­res­cent, and it reflects IR. Two cross-hair lines, 0,2 mm (ver­ti­cal) and 0.4 mm (hor­i­zon­tal) are printed on each swatch of paper before the appli­ca­tion of paint, in order to have a means to eval­u­ate the pig­ments’ trans­parency in the IR and IRR imag­ing. Among all the pig­ments and their vari­eties ever used in art these pig­ments col­lec­tion select the most used ones from antiquity to early 1950’.


2016-10-17T16:35:16+00:00

10 Comments

  1. Elisa Distefano December 10, 2012 at 10:47 am - Reply

    Very interesting! I noticed several dark “patches” in the UV fluorescence image. Are they due to some deterioration of the picture?

    • Antonino Cosentino December 10, 2012 at 4:44 pm - Reply

      Hi Elisa, thanks for your question! The black patches are not deterioration but actually modern retouches. Indeed, new paint (binder) and new varnish look dark in UV fluorescence because they had not aged enough (they need more than about 50 years to be fully polymerized) and they just absorb the UV light without emitting any greenish fluorescence such as the surrounding original paint.

  2. John Cornay April 7, 2013 at 9:28 pm - Reply

    I am interested in having a wall that has been whitewashed with emulsion so examined. Can you email me to discuss please ? John JC. Miscellaneous@googlemail.com

  3. Fernando Espinoza April 29, 2013 at 11:40 pm - Reply

    I am interested in having a multi spectral imaging study of artworks with Light Visible-IR and UV light Reflectography quiesiera know the cost of equipment and technical advice

  4. Fernando Espinoza April 30, 2013 at 12:03 am - Reply

    Please let me know multispectral system costs and technical advice. Know addition to technical specifications as wavelength reaches the IR mode system and other technical data. thanks

  5. Rene Gerritsen July 31, 2014 at 9:53 am - Reply

    Dear Antonino,
    What is the size of the area you can record without too big optical distortion.
    I’ve tried the Gigapan pro, but find it not stable enough (for my Hamamatsu) and the area I can cover with it without any (big) distortions is small. And any comments on depth of field?
    Distance ‘lens corners:lens middle’ of the painting differs quite a lot on short working distances, which gives me distortions and depth of field problems.
    For overall High Res digital IR pictures I use a High res digital camera back (80mp) so I don’t need the Gigapan for ‘normal’ IR photography.

    Would love to hear your comments.
    René

    • Antonino Cosentino July 31, 2014 at 10:20 am - Reply

      Hi Rene’, nice to hear form you, hope everything ‘s fine. Did you see these two papers on panoramic IRR. These should answer some of your questions
      A. Cosentino “Panoramic infrared Reflec­tog­ra­phy. Tech­ni­cal Rec­om­men­da­tions ” Intl Jour­nal of Con­ser­va­tion Sci­ence, IJCS Vol­ume 5, Issue 1, January-March: 51–60, 2014.
      A. Cosentino “A prac­ti­cal guide to Panoramic Mul­ti­spec­tral Imag­ing” e-conservation Mag­a­zine, 25, pp 64–73, 2013.
      they are both open access so you can download them right away. you find the lnks in my publications page on the blog.

  6. Rafael April 11, 2017 at 3:09 am - Reply

    Is there a reason why an artist will make an inscription under a painting .

    I think my painting has inscription and what appears to say
    what is more preferable IRR or IR to perform the proper review

    Ciran Regne Masy
    M
    or
    Ciran Vigne Masy
    M

    • Antonino Cosentino April 11, 2017 at 10:56 am - Reply

      Hi Rafael,
      to detect underdrawing is better IRR. Artists used to write on their canvas to take notes, regarding the final colors, for example. But there are really a great number of reasons during their creative process to jot down notes on their canvases.

  7. Rafael May 7, 2017 at 8:43 pm - Reply

    Thank you Antonino for your insight and Kind response. Rafael

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