Wratten X1 green filter

[Mspencer]

Does any one know the modern equivalent of this old system filter. Perhaps a
58 or 61 green?

[Michael Gudzinowicz]

"Mspencer" <mspe...@dur.mindspring.com> wrote:

>Does any one know the modern equivalent of this old system filter. Perhaps a
>58 or 61 green?

Wratten lists it as a yellow filter. The X1 is #11 and X2 is #13.

[JGATHOME]

My Green Series8 wratten filter has an X2 on it with no other numbers or
letters . The Yellow series 8 wratten filter has a K1 marking on it. I have
no idea how old these are...did they standardize these at some time?>

[Richard Knoppow]

jgat...@aol.com (JGATHOME) wrote:

K2 and X1 are Kodak (Wratten) type indicators. These letter and
number combinations date back to the first filters and have little
rational basis. Other filter manufacturers used other letter and
number designators (although some adopted the Wratten system), like Y2
for K2, lists can be found in many old handbooks. Some filter makers
simply named the filters, i.e. Medium Yellow.
The number only system became a standard about the mid seventies
sometime. Other systems continued to co-exist for many years. The
newer system is consistant amoung manufacturers so a #11 is the same
thing regardless of who makes it. That is not to say the quality or
exact spectral transmission will be the same but it will be a medium
Green filter and not something completely different.
There have been a tremendous number of filters offered commercially
over the years including a great many special purpose filters and some
pretty close duplications. Many of these have disappeared due to
little volume or the use of un-stable colorants.
The most commonly used filters for B&W are:
Old Wratten No. New type no. Color
K1 #6 Light Yellow
K2 #8 Medium Yellow
K3 #9 Dark Yellow
X1 #11 Light Green
X2 #13 Medium Green
G #15 Deep Yellow or Light Orange
A #25A Medium Red
C5 #47 Blue

There are dozens of others. This system is used only for monochrome
filters, not for color correction filters.

---
Richard Knoppow
Los Angeles, Ca.
dick...@ix.netcom.com

[Michael Gudzinowicz]

JGATHOME <jgat...@aol.com> wrote:

>My Green Series 8 wratten filter has an X2 on it with no other numbers or

>letters . The Yellow series 8 wratten filter has a K1 marking on it. I have
>no idea how old these are...did they standardize these at some time?>

>>Wratten lists it as a yellow filter. The X1 is #11 and X2 is #13.

The K1 is the #6 filter, which should have a factor of approx. 1.5. The
filters would be difficult to date - I'm not sure of their production
dates, but it was over a number of decades.

The book I used ("Wratten Light Filters" was published by EKC in 1945, and
it refers to filters by both the letter and numerical designations. The
correspondence was more or less standardized by that time, though
manufacturers seem to use their own "systems". For instance, I have K2
filters which are designated as K2, Y2, K2(Y) and Y(K2); X2's called an X2
or Green 2, etc. Also, B&W has its own numerical designations which appear
to be cross-referenced to Wratten numbers. Usually the spectral curves are
very similar in shape, however, the density (and exposure factor) may vary
between manufacturers.

[GRAFLEX3]

see tiffen optcal co listing green 1 is #11 Green 2 is # 13 and and the
their are 4 other greens #56, #58 #61, #64, &#74 take your pick.

[Steve Shapiro]

Please post your intended use for this filter and maybe we can help decifer
the numbers to your advantage.

The 47 blue and 61 green are used to make contrast changes in variable or
multi contrast paper used below an enlarger light source.

SS
Michael Gudzinowicz wrote in message
<77gdsk$b...@freenet-news.carleton.ca>...