Filters for 6in Goertz Artar filter slot

[gth]

Where do I get filters that fit into a 6in f:9 Goertz Artar lens filter slot?

Specfifically the three filters to make color separations on B/W film. Which was the intended use for this filter slot, right? Can I use gel filters "bare" or was there a "holder" that fit the slot? That seems unlikely. I could see that specially made thin glass filters would work.

Any information how this filter capability was used on these lenses would be welcome.

[Merg Ross]

I believe the slot to which you refer was for Waterhouse stops, not filters.

[gth]

Hmm, the lens has an iris calibrated from f:9 to f:64. This is a relatively recent lens by the American Branch of Goerz.

I was told before this is a filter slot, I believe used for making color separations. I am trying to find the original filters for this lens, if they indeed exist.

[erie patsellis]

For seperations, one typically used Wratten 29, 47 and 56 (from memory, a quick look at a Wratten chart will list the filters for separations). I used to use 2" gels myself.

[gth]

Ok, I did some research and found Kodak Wratten 2 Optical filters which replaces the Kodak Wratten Gel filters.

Kodak lists Wratten 2 as follows:

#29 Red for tricolor with #47 and #61
#47 Blue for tricolor with #29 and 61
#61 Green for tricolor with #29 and #47

So... I cut these to size (What?) and slip them into the lens slot?

What would be the advantage vs having a front-of lens mounted filter?

Do I need a holder for the slot?

[Merg Ross]

The lens that you have was most likely designed for photo-engraving, although excellent as a field lens, contrary to the opinion of some. For years, I used a 19" Artar with excellent results. The slot was of no use, and I used front or rear mounted filters.

However, as a lens used in the Gaphic Arts, the slot was for inserting Waterhouse stops to control screen lines when making half-tones. I did this when working as a GA cameraman. My suggestion would be to use front mounted filters.

[Curt]

The Apo Nikkor lenses that are newer have the slot and sliding covers too, I bought a set of six filter holders, thin brass that was bent over so gel filters can be placed in them. They were made by Nikon for the lenses. I have two of those lenses but have not put any filters in them.

Back to the question, I have a 19" in barrel and a 16.5" in barrel, both Artar lenses. I also have the 9.5 and 10 3/4 Artar lenses in barrels, they all have the slot and slot cover. Were they design for the Graphic Arts industry also?

Would modern glass filters, which I use, be better than the gel filters or the Lee or other resin filters available?

I'm glad that I have a front mount for the small ones and an Ilex for another pair of 16.5" and 19", it makes life easier all around, and no filter slots.

Curt

[gth]

It sort of begs the question why they designed the lens that way.... and many were, apparently? There must be some distinct advantages, going to all that trouble, slot in the lens body, rotating cover ring etc. vs just putting a thread on the front lip of the lens, or design for a push on filter even.

There must be a handling/optical/practical reason they were made that way.

??

/gth

[Jan Pedersen]

Ignorance is bliss, why don't you read what Merg Ross has been trying to tell you?

[erie patsellis]

Pretty much what Merg said, I used both square and elliptical apertures frequently, along with flashing, and other tricks to modify the response curve. Now it's just a few mouse clicks. Not all the old ways are better, IMHO.

[sun of sand]

I cut wratten gels and glued them to waterhouse stops

I have more waterhouse stops to carry around but to me beats carrying/changing large filters
and being inside the lens you may end up with less flare than youd get with front mounted filters

[gth]

As a matter or curiosity I'd like to learn how these lenses were used originally. I understand we can use front or back mounted filters. That is not the issue.

But this lens was designed in a special way and some engineering attention was paid to providing an internal lens filter slot... and it was not just some crazy lens designer. I have seen a site (forget name right now) that offer other types of lenses with this feature. So it must have been an industry "standard".

I'd like to know how that worked and why they did it that way.

[gth]

So maybe I am confused because someone called it a filter slot and it was not really used for separation filters but for stops of various designs.

The site I mentiond before is glennview.com and he has this on his site:

"60mm F9 Apo Nikkor, coated, barrel, lens has filter slot that accepts included gel filter holder, Mint, $450"

So, hmm?

Sorry to harp on it but it's interesting to find out how these older technologie worked.

[sun of sand]

no need to be sorry
people just need to answer a question
and if they aint got nothing
to say so

I don't know first hand
I've read they used filters

Are these "filters" what I would think of as being waterhouse stops of different design
OR
Were there actual colored filters in use

[Ernest Purdum]

In the beginning, it was found that the tiny dots which made up the pictures used in publishing newspapers (and other purposes) worked better if they were not round, but square or some other shape made of straight lines. At that time, most stops were Waterhouse type, so it worked well to just make a series of stops with square holes. When iris stops became common, lens makers found their products would appeal to more customers if, in addition to the slot, an iris was also provided. So long as the lenses were sold in barrel mounts, this was easy to do.

It was always possible to cut a gel filter and stick it in the slot. The type of filter was up to the user. If your setup was sufficiently rigid, three color work was certainly possible. There were several advantages to placing filters in the slot rather than in front or behind the lens. Enough people did it so at least one maker, Nikon, made it more convenient to do so.

All the lenses I know of with both iris and Waterhouse provisions are "process" lenses, designed specifically for use at or near 1:1 magnification ratio. Many are "dialyte" symmetrical lenses. Others are Tessars or other asymmetrical design, mounted reversibly so that the "front" of the lens may be turned toward either the subject or the film, whichever is the larger.

The dialytes, of which the Apo Artar is an example, have many pleasant attributes, among which is a lack of fussiness about reproduction ratio. Photographers found out they could get pleasing results even in landscapes, which is as far from 1:1 reproduction as you can get, short of astronomy.

[gth]

Thanks everyone for great information!

Anyone know the specs on the Waterhouse stops or filter size for this lens - AM. Goerz APO Artar 6" (size etc.) .

/gth

[Curt]

To add to the issue, I have a half dozen filter holders in brass with black coating that were made to hold gelatin filters. The opening is exactly the same for all of them and they were labeled filter holders.

Now one could call them a set of waterhouse stops of the same aperture if they want. Since they are not numbered it would be hard to know which is which.

[Merg Ross]

Hi Curt, I think what you may have are the filter holders for the Apo Nikkor Process lenses. Great lenses, are they not? I have the 450mm, complete with Waterhouse stops, but not the filter holders.

I believe the OP was asking about the Goertz Artar lenses. To my knowledge, Goertz only provided Waterhouse stops and not filter holders. Hence my original answer.