RE: Seeing through the grass with IR

["Jason Revell (in5)" <jason.revell@xxxxxxxxx>]

>Those are interesting photos that Andy @ RIT put-up on the site.  Last
year,
>while in Ireland, I had hoped to improve the delineation of some
>incised-carvings (more than 1000 years out in the weather) I was
>photographing.  I only had some Konica 750-120 and an R72 filter with me,
so
>I stayed with my trusty Plus-X.  Later that day, I  rationalized-away my
>reluctance to try it out by recalling that most of the "hidden-image"
>detective-work I've seen in the past was done with UV and not IR, and I
>should not have expected to see detail in a monolithic (literally) subject
>with infrared.  Now, I'm not so sure.  Any ideas out there?  I can get
>"almost real" IR with the Konica and a #87 filter.  Next year, I'll take
the
>HSIR 70 mm. with me if the potential is there.
>
>Pete Schermerhorn, in the glorious Berkshires


It all depends on what the image was created with in the first place.

You will find that anything done with a carbon based pigment (and some
others) will allow a "hidden-image" to PERHAPS re-appear by the use of IR
reflectography.  I do this alot at work here with very faded pencil
inscriptions on the back of paintings stretches and on watercolours were the
artist has signed in pencil or faint watercolour paint.  It does work, but
don't expect miracles.

However, sometimes they are written in Irongall ink.  If a faint inscription
is photographed in IR you will find the whole thing disappears.  But with UV
reflectography it will show as clear as day.

As with most things you need different techniques depending on your
materials.  Now if only knew what we were trying to record/analyse before we
did the test's to identify it, it would make life so much easier  ;-)

Perhaps take a video camera (with IR filter) with you and have a look, it's
what I do.

Jason
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