Hoya 81 series filters?

[CasioCassette]

I have owned the 81B filter for a couple of years and use it regularly, and had the option to buy a new 81A and an 81C filter at a real bargain price, at different filter sizes, so I thought why not.

What puzzles me though is the color of the filters in a side-by-side comparison. I expected the 81A and C to also be straw colored like the 81B, but they are definitely more orange or salmon color.

They seem to be from different generations (?) of Hoya filters, the Hoya logo is different, the font, too, and while the 81B says "Made in Japan" the 81A and C only say "Japan".

Am I correctly assuming that the 81A and C are earlier models?

But even so, how can the colors be so different? I know it's only a photo but in reality the difference is even more evident, the straw colored 81B is different and doesn't seem to be the "in-between color" it's supposed to be.

Any thoughts?

 

[Ian C]

The Wratten 81 series of warming filters are arranged from weakest to strongest as

81A, 81B, 81C, 81D, 81EF

The explanation is given in the table in the Wikipedia article “Wratten Number.”

https://en.wikipedia.org/wiki/Wratten_number

These were intended to fine-tune the color recorded on positive color transparency film (slide film), which has no color correction after processing. So, any color adjustment must be made at exposure.

 

[CasioCassette]

Thanks Ian, I use my 81B for color slides for this purpose. What I'm wondering about is why the 81B is so different from the A and C, it doesn't appear to be the in-between color to me. As I said in reality the difference is more obvious than on the photo I posted.

 

[Ian C]

The effect produced by a filter is what is important. It’s appearance to our eyes can be misleading.

 

[CasioCassette]

Good point, I suppose I was misled by the colors a little. Thanks!

 

[Christiaan Phleger]

Older filters can have had color shifts from age. I still keep a set of Nikon B2's for use under strong tungsten lights with digit-all.

 

[JensH]

... some so called 81's seem to be KR's. Reddish/pink. Just saying.

 

[Christiaan Phleger]

Wasn't B+W and Heliopan filters called KB and KR for Kelvin Blue and Kelvin Red?

 

[JensH]

Wasn't B+W and Heliopan filters called KB and KR for Kelvin Blue and Kelvin Red?

....or Konversionsfilter Blau and Rot in German.
I once had even one with 81A and KR 1.5 on it...

 

[DREW WILEY]

I have the same peculiarity in my own set. It seems far fewer of the Hoya 81B's sold, and the ones you find were manufactured earlier. I rarely use mine. If I need serious Kelvin correction for especially deep blue shade, particularly at high altitude, I jump from the 81A to 81C, and seldom even carry an 81B. The more pinkish later versions are preferable. KR1.5 and KR3 are Euro designations even a little more reddish than the 81 series. That system is slightly different. For example, if you combine two KR1.5's, it equals a KR3. But if I'm traveling extra light, I might combine a pinkish 2A salmon skylight filter with an 81A to approximate a KR3, at least in hue if not in full density.

Both systems have their own validity, depending on what specific color film you're working with, and what the actual light situation is. So I own both in several diameter sizes, plus a selection of skylight filters.

 

[JensH]

I have a set of 81's (and their blueish 80's counterparts) to change color temp without destroying the magenta/green balance.
Got them for making chromes on the microscope, a lot of optics here making "hardware color grading" not easy...

 

[DREW WILEY]

The tradeoff between magenta and green categories, especially when you have to juggle blue versus yellow at the same time, is indeed a delicate balancing act, since color films don't see hues quite like we do, and not quite like each other either. Everything depends on the specifics. And colors in nature often differ from artificial colors in this respect. Test, test, test.

The old Wratten filter handbook is quite interesting given the truly wide selection they once offered, including specialty microscopy filters. Of course, lots of those gels faded quickly, and replacements of the rarer versions can be pretty darn expensive. But if I ever manage to get into microscopy again, I'll be well set up with filters at least.

Seems that you like darkfield work, Jens. There sure are a lot of amazing frightening Aliens in the mini-universe.