[LargeFormat] Confused Uncle Seeks Truth

[Ken Sinclair]

Dear Uncle Dick

There really is a Santa Clause.. the moon is really a ball of cheese and,
believe it or not there really IS a filter such as you describe to do what
you want.

Its use is generally in photomicroscopy to enhance haematoxalin (red) stain
with colour films.. its a called a "dydimium" filter and works wonders
beyond your wildest dreams.

>    1.    Does it really work?

Sure as the little Irish guys with long hair and funny hats enjoy a pint of
Guiness

>    2.     Does it work in red only or does it extend to orange and yellow?

Red only... never seen any hominid  with green or yellow blood

>    3.     How much of a boost is there?

WOW!!!... weellllll... almost

>    4.     Is it an effect that is dependant upon the angle of the sun or
>rotation of the filter like a polarising filter?

No

>    5.    Does it affect red tones in a negative and a transparency film
>equally?

Yes

>    6.     Can your eye see these changes in the red tones when you look
>through the filter at the scene that you want to photograph?

It's been a few years since and I am becoming too old to rememebr some of
the technical stuff.. I'll have a look in some literature

>    7.    Is there an exposure increase needed?

It's generally used in the light-path... I can however, recall an article
about 20+ years ago about using it in front of the lens and a colour Kodak
film for phototomicroscopy...I seem to recall images of an EIIR "pillarbox"
(mailbox to those of non-Brit persuasion) with with and without dydimium..
made quite a difference

>    8.     Is there a similar filter that works on other colours? ie blue or
>green.

There are quite a number of pass/cut off combinations...but mostly for B/W
contrast enhancement.. again in photomicroscopy..... but I don't think
there's any colour "enhancement" ones  for the other areas of the
spectrum.... but I'd have take a look

Ken
>     I hope someone in the landscape line has had some experience with one
>of these and can report. Many thanks for the help.
>

 [||/\/\/\/\//\/||        Ken Sinclair RBP, FBPA.
 [||                            ||-|    Applied Photographic Services
 [||                            ||   |  Lethbridge,
 [||                            ||   |  Alberta, Canada,
 [||                            ||-|   (403) 381-1654.
 [||\/\/\/\//\/\||       photo1@telusplanet.net
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