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Photo Forum / Film Photography / Darkroom / April 2005Kodak Polycontrast filters
Hi all ! I got a Kodak Polycontrast filter kit ( model A ) It's an older one, under the lens 7 filters kit. Anybody knows if exposure compensation is needed for different grades ? I was told that there was some kind of "exposure calculator" for this kit, but unfortunately I can't find it. Thanks,  SignatureIgor http://www.arrakis.es/~igapop Yes, there was. Write to Kodak, in case that thought didn't cross your mind. > Hi all ! > I got a Kodak Polycontrast filter kit ( model A ) [quoted text clipped - 4 lines] > unfortunately I can't find it. > Thanks, yes compensation is required. I don't use a calculator - I do test strips for each contrast grade change. Bit I looked in my Kodak B&W dataguide sixth edition, copyright 2001 and found on page 48 the following: "There is no change in effective paper speed within the range -1 to 3 1/2 and within the range 4 to 5+. You need to recalculate exposure when you switch from one range to the other, or when you remove the filter completely or add a filter when you have been printing without one." The explnation then goes on to describe how to set the calculator (page 49). I'll give you an example to show the factors: If the "no filter" print time is 10 seconds, then the "-1 to 3 1/2" range is 20 seconds and the "4 to 5+" range is about 41-42 seconds. Thus for going from no filter to a "-1 to 3 1/2" doubles the time. Going from no filter to a "4 to 5+" increases the time by a factor of slightly more than 4. Going from a "-1 to 3 1/2" to a "4 to 5+" will about double the time (20 seconds to 42 seconds, for example) This calculation seems constant. The same multipliers apply to all paper speeds, chemicals, etc (or at least there is no compensation on the calculator dial for anything but filer grade changes). Hope this is helpful. > Hi all ! > I got a Kodak Polycontrast filter kit ( model A ) [quoted text clipped - 4 lines] > unfortunately I can't find it. > Thanks, This is for the NEW set. The old set was different, and each filter required a different factor. You need the calculator. > yes compensation is required. I don't use a calculator - I do test strips > for each contrast grade change. Bit I looked in my Kodak B&W dataguide [quoted text clipped - 13 lines] > Thus for going from no filter to a "-1 to 3 1/2" doubles the time. > Going from no filter to a "4 to 5+" increases the time by a factor of > slightly more than 4. > [quoted text clipped - 15 lines] > > unfortunately I can't find it. > > Thanks, Yes, it's an older one. And yes, I'm afraid that I need the calculator. The problem is that I don't know where to get one.. Thanks, SignatureIgor http://www.arrakis.es/~igapop > This is for the NEW set. The old set was different, and each filter > required a different factor. [quoted text clipped - 47 lines] > > > unfortunately I can't find it. > > > Thanks, Write to or call Kodak. They'll be glad to help you! > Yes, it's an older one. And yes, I'm afraid that I need > the calculator. The problem is that I don't know where [quoted text clipped - 60 lines] > > > > Igor > > > > http://www.arrakis.es/~igapop Sorry - you are right - the title says "When you change from one Polymax filter to another:" I don't have anything relating to the older filter sets. I have one that is about 30 years old and has 5 filters, but I don't use it - it's on the "museum" shelf. > This is for the NEW set. The old set was different, and each filter > required a different factor. [quoted text clipped - 47 lines] >> > unfortunately I can't find it. >> > Thanks, > This is for the NEW set. The old set was different, and each filter > required a different factor. Looking at the calculator in an old databook, listed below are the adjustment factors, which you could use to set up your own calculator. As an example, if you expose the first print with white light at 10 seconds, the following would be the time for various filters: White - 10 seconds 1 - 15 " 1-1/2 - 15 " 2 - 14 " 2-1/2 - 16 " 3 - 20 " 3-1/2 - 25 " 4 - 50 " If a filter was used for the first exposure, then the times would be appropriately adjusted based on the above relationships. The notes state that the above are for a tungsten light source. They also recommend opening up the lens if exposures exceed 60 seconds. Thanks a lot to all ! Best wishes, SignatureIgor http://www.arrakis.es/~igapop > > This is for the NEW set. The old set was different, and each filter > > required a different factor. [quoted text clipped - 18 lines] > The notes state that the above are for a tungsten light source. They > also recommend opening up the lens if exposures exceed 60 seconds. Polycontrast filter sets requires exposure compensation for each change in filter, PC II and III sets require less compensation from filter to filter but changes are still required. The calculator will get you close but testing is still necessary. Signaturedarkroommike ---------- > Hi all ! > I got a Kodak Polycontrast filter kit ( model A ) [quoted text clipped - 4 lines] > unfortunately I can't find it. > Thanks, |
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