Red filter in enlarger throwing off sharpness

Steve Smith · May 5, 2010

One idea to try: Place something under one side of your easel so the plane of paper is at an angle to the horizontal - about 1/2" higher at one end would do.

Focus so that the middle area of the print is in focus.

Stop down by your usual amount.

Make a print.

You should then be able to work out the distance over which you get good sharpness. A simple calculation will then show you what the depth of focus at the paper is.

Steve.

RalphLambrecht · May 5, 2010

Steve Smith said:
One idea to try: Place something under one side of your easel so the plane of paper is at an angle to the horizontal - about 1/2" higher at one end would do.

Focus so that the middle area of the print is in focus.

Stop down by your usual amount.

Make a print.

You should then be able to work out the distance over which you get good sharpness. A simple calculation will then show you what the depth of focus at the paper is.

Steve.

Steve

No chance. You won't see any change. Start with a 1/4 inch board, then 1/2 inch... You'll get there eventually, but not with a piece of paper.

CBG · May 5, 2010

RalphLambrecht said:
... your printing paper won't be flat enough to stay within 0.2 mm ...

Thank you.

For practical purposes, the thickness of a sheet of paper just won't matter.

David A. Goldfarb · May 5, 2010

Anyone reading this discussion who has decided to dispose of their vacuum easel, just send it my way, and I'll take care of it for you.

MattKing · May 5, 2010

RalphLambrecht said:
That's not what I meant. I meant, I never trust what I'm told by an 'authority'. Heck, I don't even trust myself sometimes.

I trust you Ralph .

But I also trust David, and Steve, and Ken, and Dietmar ...

What is a trusting soul to do:confused:

clayne · May 5, 2010

I never use a red filter for focusing. I never use it for anything actually - and found that it offers little protection to fogging paper during focusing/realignment anyways.

I always use completely fixed blank sheets for a given size to focus on or align against.

RalphLambrecht · May 6, 2010

David A. Goldfarb said:
Anyone reading this discussion who has decided to dispose of their vacuum easel, just send it my way, and I'll take care of it for you.

Good point! There is another thread discussion 'most overrated features'. We could list them there.

Tony Egan · May 6, 2010

It's a tight game and we're into out 4th deuce...
For me it boils down to work habits I am happy with. I've removed the red filter from my enlargers as I never use them. Always focus wide open with no MG filters in the way with the scope on the back of an old print of the right size but not always of exactly the same paper type. It's a white surface for ease of focusing and, I'll admit, "peace of mind" in terms of focus accuracy even though the mathematics may prove it makes not difference.
I occasionally do test strips with curled paper and skip the glass over the top. The sharpness is noticeably different at the edges. An extreme example perhaps, but I prefer to avoid any "sloppy" practices in my routine.

Steve Smith · May 6, 2010

RalphLambrecht said:
Steve

Here are the contact details for Tohkai. They make the Peak enlarging focusers. Maybe they can tell you, and then you tell us.

Tohkai Sangyo Co. Ltd.
24-2 Yushima,3-chome Bunkyo-Ku
Tokyo, Japan

tel:- 0081 3 3834 5711
web address:- www.peak.co.jp/
e-mail:- ex_div@peak.co.jp

I have just sent a message. Watch this space for a reply!

Steve

RalphLambrecht · May 6, 2010

Tony Egan said:
...I've removed the red filter from my enlargers as I never use them...

That reminds me. My Durst L1200 has a very nice holder for the red filter. It easily swings into and out of the light path, precisely snapping into a fixed position. I removed the red filter from the holder and replaced it with a #5 contrast filter cut to size. Then, I bought a spare holder, mounted it too but inserted a #0 contrast filter. Now I can use them for split-grade printing if I want to.

RalphLambrecht · May 6, 2010

Steve Smith said:
I have just sent a message. Watch this space for a reply!

Steve

Thanks for doing that Steve. I'm very interested in their explanation. Maybe, Patterson would be another source to ask. I'll see if I have a contact for them. Does anyone have a contact of Magnasight and Microsight focusing aids?

Steve Smith · May 6, 2010

I have also sent the same message to Bestwell Optical, the manufacturer of the Magna-sight, Micro-sight and Mini-sight.

EDIT: I have also contacted Patterson. Their website not only publishes the normal contact e-mail but also a separate e-mail for technical queries.

Steve.

RalphLambrecht · May 6, 2010

Steve Smith said:
I have also sent the same message to Bestwell Optical, the manufacturer of the Magna-sight, Micro-sight and Mini-sight.

EDIT: I have also contacted Patterson. Their website not only publishes the normal contact e-mail but also a separate e-mail for technical queries.

Steve.

Steve

Sounds like we will get to the bottom of this.

Tony Egan · May 6, 2010

RalphLambrecht said:
That reminds me. My Durst L1200 has a very nice holder for the red filter. It easily swings into and out of the light path, precisely snapping into a fixed position. I removed the red filter from the holder and replaced it with a #5 contrast filter cut to size. Then, I bought a spare holder, mounted it too but inserted a #0 contrast filter. Now I can use them for split-grade printing if I want to.

With my Beseler 45 I created a square plastic MG filter holder cut out from a piece of plastic that had a raised ridge on it in which a filter would sit nicely. I attached it via the screw hole which the red filter originally used. Works like a charm. It is a diffuser colour head but using the colour dials with MG paper drove me mad as the white times would move each time a dial changed.

MattKing · May 6, 2010

RalphLambrecht said:
Steve

Sounds like we will get to the bottom of this.

So to speak

Sparky · May 6, 2010

RalphLambrecht said:
I use mathematics, which is one of the 'authorities' I respect.

I'm not trying to pick on you Ralph - just so you're aware of my intent here - I was remarking on the nebulous nature of 'fact' and it's relation to 'opinion'. The whole problem with numbers is in the interpretation of what those results mean. That's where the problems come in. But since we're all being picky about stuff in this thread I thought I'd take the opportunity to correct you (insert smiley face) and suggest that it's arithmetic and NOT mathematics that you're using. Any mathematician would tell you that any mathematical proof is only a statement of fact in the narrowest possible sense.

Sparky · May 6, 2010

RalphLambrecht said:
Good point! There is another thread discussion 'most overrated features'. We could list them there.

Ha. Can't agree with that either...! Again- not trying to be a troll... but I just had to say something. I've found that I've had far better results printing on paper sucked flat than curled up into a tube. Call me crazy, but it works for me.

David A. Goldfarb · May 6, 2010

When the vacuum easels start piling up on my doorstep, Sparky, I'll save a couple for you.

Steve Smith · May 7, 2010

Some results are in:

The contact e-mail for Magna-sight is Lisa Weingarten. She says:

Hi, I always have a scrap paper under the Magna Sight of the same weight of paper that you will be printing on.

Although this sounds more like personal opinion than the manufacturers advice.

Conversely I have had this reply from Roger Parry at Patterson:

Hi Steve, There is no need to put a piece of paper under the focus finder.

I asked Roger if this was due to paper thickness being designed into the device and this was his reply:

Hi Steve
I was not around in the company when the focus finders were designed but from my own experience the finders work perfectly without a sheet of paper under them. In fact a sheet of processed and dried paper will be different from an unprocessed sheet and you would not want to waste a second sheet of paper on every print you make.

So there is another variable in the equation. The difference between a sheet straight out of the box and one which has been processed and dried.

Just waiting for one more response from Tohkai, manufacturer of the Peak device.

Steve.

David A. Goldfarb · May 7, 2010

Who needs to waste a second sheet of paper for every print? I have a folder near the enlarger with unprocessed scrap sheets of the various kinds of paper I use marked with the paper type and "FOCUS," so I don't confuse them with the sheets I'm actually printing on.

Steve Smith · May 7, 2010

David A. Goldfarb said:
Who needs to waste a second sheet of paper for every print?

Yes. Just the one sheet would do........... or not - depending on your point of view!

Steve.

RalphLambrecht · May 7, 2010

Sparky said:
Ha. Can't agree with that either...! Again- not trying to be a troll... but I just had to say something. I've found that I've had far better results printing on paper sucked flat than curled up into a tube. Call me crazy, but it works for me.

You are absolutely right. Statements like 'I had far better results' or 'works for me' are hard to quantify. I'll rather stick to the math, but I can appreciate that there is some value to that fuzzy feeling when one believes to have done the best thing possible, even if it doesn't matter much.

RalphLambrecht · May 7, 2010

Steve

Thanks for going through the trouble and for the update.

We already know that using a piece of paper is more precise, not necessary because too minute to matter, but nevertheless, more precise. However, the question we want to have answered is if the manufacturer made any assumption about paper thickness when the device was designed, or was it designed to work on any surface.
Maybe you can pose the question in this way.

Looking forward to Tohkai's answer and thanks again.

Steve Smith · May 7, 2010

That is the question I asked Roger Parry but as he was not at the company when it was designed, he doesn't know the answer.

I have sent Roger another e-mail explaining why I was asking but I don't think he is in a position to find the answer. I don't think I will get any more information on the Magna-sight either so we will have to wait and see what we get from Tohkai.

As you say, using a piece of paper is not necessary but I don't agree that it is more precise. It may be but if the manufacturer has compensated for the paper then it would be less precise than not using it, not more.

I think the answer is to use a piece of paper if you want to and don't if you don't want - it won't make any practical difference either way.

Steve.

Photo Engineer · May 7, 2010

I have dumb question.

I was taught to focus on a sheet of paper without the red filter. I was taught that there were two types of grain focusers with different focal planes which were stated "on the box", but I never saw any such statement on any that I own or bought or used.

I was also taught to use the red filter only for composing the final image with the actual paper in the easel.

Now, since I do mostly color, I use no red filter of course, but this is from waaaaay back when I did B&W.

So, the question is...... why use a red filter to focus when it isn't needed?

PE

Red filter in enlarger throwing off sharpness

Steve Smith

RalphLambrecht

CBG

David A. Goldfarb

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MattKing

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clayne

RalphLambrecht

Tony Egan

Steve Smith

RalphLambrecht

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Steve Smith

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Tony Egan

MattKing

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Sparky

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David A. Goldfarb

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Steve Smith

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RalphLambrecht

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Red filter in enlarger throwing off sharpness

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