Why is there a red-filter and a clear-filter ?

shoot6x7 · Dec 5, 2015

I know what the red one is for, I even know how you'd use the second frame to perch a multigrade filter on, but why would it have a clear plastic filter ?

Does anyone have any idea as to its use ?

Thanks,
Ron

Sirius Glass · Dec 5, 2015

The red filter it placed in front of the enlarger lens so that the enlarger light does not need to be turned off while the paper is placed in the easel. Then the red filter is moved out of the way for exposing the paper.

The clear filter is a filter holder for contrast filters, originally Polycontrast filters.

AgX · Dec 5, 2015

Over here with packed food, the photograph at the package is called "serving proposal".
Maybe that clear filter is installed as hint to install a filter there. Rather a placeholder than a proposal.

RobC · Dec 5, 2015

the clear filter is usually a semi opaque diffusing filter used for metering with a colour analyser. Methinks someone has replaced it with clear but I could be wrong and its meant for placing contrast or colour correction filters on.

But I've never seen circular filters for that purpose.

shoot6x7 · Dec 5, 2015

If it was just for a multigrade or polycontrast filter I would expect the lower one not to have the clear plastic disc. Hence my question.

The plastic filter itself is cut with the same precision as the red one is and that's what makes me scratch my head.

Thanks for the comments so far.

Sirius Glass · Dec 5, 2015

Hmmm ... a head scratcher <<puzzled>>

rorye · Dec 5, 2015

Maybe for partial diffusion, eg vaseline around the edges?

Sirius Glass · Dec 6, 2015

Oh, a slippery slope.

Ian Grant · Dec 6, 2015

The Durst colour enlargers came with the diffuser as Rob says and also a red filter, someone's put them on the same post. You'd use one or the other but not both.

Ian

AgX · Dec 6, 2015

RobC said:
... but I could be wrong and its meant for placing contrast or colour correction filters on.

But I've never seen circular filters for that purpose.

It only would make sense if one would want to place a filter smaller than the filterring on it. Filters that still must be large enough to cover the exit cone.

On could think of foils, but I assume the filterring is small enough to take the smallest standard size. And has someone filter foil snippets in house? (Actually I got...)
Then would remain smaller camera filters. But they then, as snippets, could glide out of center.
It could also be used as template for cutting foils to size.

I think the clear pane is a placeholder though with some very restricted use itself. Thus one is better off with it than an empty filterring.

Ian Grant · Dec 6, 2015

The missing diffuser is for use with the Durst colour analysers. That was the only two uses of these Durst filter holders. As it was supplied with the colour heads only you didn't need to use separate filters for MG papers. The Durst B&W enlarger (condenser type) all had filter drawars

Ian

AgX · Dec 6, 2015

But the topic here is not a diffusion but a clear filter.

Ian Grant · Dec 6, 2015

AgX said:
But the topic here is not a diffusion but a clear filter.

Someone's changed it, Durst never sold one like that.

Ian

AgX · Dec 6, 2015

I did not know that this was a Durst one.

RobC · Dec 6, 2015

it could be used to drop a lens effect filter onto it such as a softar or some such which doesn't fit the enlarging lens.

RobC · Dec 6, 2015

AgX said:
I did not know that this was a Durst one.

I assumed it was durst becasue it looks just like mine but don't know if other makes use the same "accessory" bit.

AgX · Dec 6, 2015

Or to put diffusing or so particles on it. It is good for fingerprints too.

RobC · Dec 6, 2015

I rekon its from a durst Modular 70 but it may fit other models of the 6x7 format.

shoot6x7 · Dec 6, 2015

It is a Durst part, sorry should have stated that, bought from eBay to replace a missing one for my M805.
I have an L1200 and a pair of M605's so can confirm it's sized for 6x7.

From its condition, I'd agree that it's likely from a Modular 70's vintage.

RobC · Dec 6, 2015

I suggest mod 70 because I don't think its big enough for the L1200. Whether it fits the 805 I don't know. They all use different sizes as the reach of the rod and the center of the filter are different on the bigger enlargers.

ic-racer · Dec 6, 2015

Did you try it? What does it do?

Ian Grant · Dec 6, 2015

The same filter holder was used for many Durst models, M601 onwards.

Ian

shoot6x7 · Dec 6, 2015

It does fit the M805, centres over the lens centre axis. The one for the L1200 is larger and longer, the ones for the M605 are smaller and shorter.

I received it a week ago and haven't had a chance to play with it in the dark yet. The clear plastic looks very inert so am suspecting that it is a place holder.

pentaxuser · Dec 6, 2015

If it's a place holder for another filter such as a MG filter then why bother with a clear insert. An empty holder will act as a place holder just as easily, won't it?

Still a puzzle to me

pentaxuser

RobC · Dec 6, 2015

shoot6x7 said:
It does fit the M805, centres over the lens centre axis. The one for the L1200 is larger and longer, the ones for the M605 are smaller and shorter.

I received it a week ago and haven't had a chance to play with it in the dark yet. The clear plastic looks very inert so am suspecting that it is a place holder.

If you ever need some diffusion material for colour metering, then you can use some Lee Filters Leelux400 and cut to fit. Not sure if the density of it affects the meter though. I don't think so for colour balance. Obviously would for exposure time.

Why is there a red-filter and a clear-filter ?

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