Re: Filter equivalent test

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

>According to my 1925 Wratten Light filter catalog, #24 is called
>'Projection Red' (whatever that might be).

My oldish (1971) Kodak manuals give the remarks about the 24 as follows;
"For "two-colour photography" (daylight or tungsten) and for
white-flame-arc, tricolour projection."
I guess this projection is made from three different "slides" and each
projected with the relative colour to give the effect of a full colour
slide ?  It gives 1 or 2 line comments about all the Wratten filters and
like your self I have not looked at them much either, I may have to try
and get a few to try out over the summer for work.
>Never looked at the 'reds' carefully, but there is an staggering
>number of those (take a seat please):
>
>23 E (Red)
>23a E Red (light)
>23b 2-Color Red
>24 Projection Red
>24a Projection Red (light)
>25 A (Tricolor Red)
>[note WJ: seems as if "25A" has a totally different meaning than 23a
>or 89B....the latter being part of the Wratten system itself, the
>first more a translation of '25']
>26 Stereo Red
>27 Stage Red
>27a Stage Red (light)
>28 Cine Red
>29 F


Don't forget the 70 filter !  Could be quite useful for the Ilford I
would guess as it blocks all below 650nm and has only 40% transmission
at 680nm.  It says it is used for making separation positives from
colour negatives.

>Fascinating book....you won't find the same hairsplitting
>differences in the current Wratten catalog....and it has that lovely
>old smell as well....:-))

The old books always smell the best  don't they ! :-)

Jason Revell
jason.revell@xxxxxxxxx



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