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Anyone have any experience with VARYCON VC filters? Comments? Problems? Results?
These are/were made in Croatia by FotoKemika. I've got a new, gelatin set marked 0-1-2-3-4-5 in 12" square. The colors look like my Ilford VC filters. I assume they come/came in other sizes. I have no idea what equipment would use 12" VC filters, but I assume they will work fine for me.
I don’t know anything about FotoKemika, but my 8x10 enlarger head takes 12” filters. It’s a Beseler 45 with 8x10 conversion head.
Ed
Mystery solved!!
A quick test would be to compare a print of a step wedge made with the #5 filter to a print made with a #47 blue filter. To test the other end, the same, but with the #0 filter compared to a #58 green filter. (Also a good test for faded filters).Quote:
Originally Posted by xkaes
Doremus
Never used VARYCON VC filters, but let me say what I think.Quote:
Originally Posted by xkaes
Varycon was optimized for fotokemika manufactured papers, sure you know "Fotokemika ceased all production in June 2012. The company currently exists as a distributor of medical films and materials made by other manufacturers."
You can control contrast of Arista and Ilford VC papers, and I'd say also of any variable contrast papers, I guess.
Single problem it may happen (IMHO) is you have to vary exposure when you use a different filter. Of course any VC paper manufacturer make their contrast filters color equilibrated to not have to vary exposure, or to telling an easy calcuation, as you know with ilford time for filters 00–31/2 is the same; for filters 4–5 is double time.
This color equilibrium depends on the global spectral sensitivity of the particular paper, a manufacturer may want to formulate all branded papers with same spectral sensitivity in order to conserve easy exposure calculation when changing the filter. This is what it should be checked when using another brand filters. Well this can be calibrated by you...
So IMHO what it may fail with Varycon filters used with other brands of paper is that easy exposure calculation to conserve (I guess) the mean grey after fiter change.
Ilford vc papers are made of a mix of 3 emulsions, I gess it is a mix and not 3 layers of emulsions, each component is blue sensitive but more or less insensitive to green. After mixing emulsions grains of each compoment have to conserve its own sensitization (and spectral response) as once dye sensitization it is made it remains for the crystal, even after washing because the dye molecules are well tied. Different dyes in the mix perhaps should be "compatible" at the concentration remaining after washing.
Regards
Durst L184 10x10 condenser enlarger (e.g. V184 head) uses them, I know. I have a set of Ilford 12x12 VC filters and it took sometime to find them.Quote:
Originally Posted by xkaes
If you can find someone who needs that size and you can get away with a smaller size (e.g. 6x6), I think that would help the community overall than cutting down those big hard to find ones...
But having said that, they are yours to do with as you wish...
Good find!!
Thanks for the response. Makes me glad I don't use 8x10!
I normally use Ilford VC filters, but I ran my own test to determine exposures for each filter. I found that the Ilford exposure recommendations were very close most of the time, but some were not. And since I ran tests on all of their filters, I created a table for exposure adjustment when switching from one filter to another.
I will do the same thing for the Varycon filters -- rather than repeat the lessons/mistakes of history.
I agree. My issue is that I use a Beseler CB7 that needs 7" filters. I have a set of Ilford 6" filters for my 45 MXII, but they are too small for the CB7. I have been using under lens filters on the CB7, but wanted over lens filter. The only ones I could find that were 7" or larger were these 12x12" Varycon filters. I've got the cut them down to 7x7" -- actually a tiny bit bigger.Quote:
Originally Posted by Len Middleton
The scraps? I won't throw them out -- for possible future projects.
That makes perfect sense, and really your only solution was the 12x12" filters, as 6x6" is typically the next size down.Quote:
Originally Posted by xkaes
Hope it works out well for you.