Changing the size of the image upon the easel and its impacts upon the lens aperture

[redbandit]

23cII

dichro S color head
Using the manuals color knob settings.
645 negative, head at 2x2 setting beseler 50mm lens 5.6 aperture.
5 seconds on timer

Last night i did a test print comparing the beseler manual settings to the Foma guidelines..

The foma chart made an image that was alot darker but mostly viewable. Beseler was far better.

Tonight did two prints using beseler manual knob settings.

The enlarged section came out really really better. i can see 90% or more of all the branches.. but its still a tad blurry and i guess i have alot of vignetting on the edges as alot of solid trees have become wavy in appearance..

I did a nice 6x9 enlargement of the entire frame.. kept the settings in place... most of the image is just black..

SO a question pops up to mind..

Even if both images on the easel were fully in focus... should i expect to NEED a change in contrast setting or aperture between the two?

 

[redbandit]

I did that big enlargement again... and learned a few things.

I upped my aperture to f/8 from f/5.6 and used 7 seconds on the timer. Things were much much better, but i realize that when i took the image the branches were caught in a surprise burst of wind creating some blur.

I was curious and put the pizza eating negative back in. Before to even get a visible image i was down to using grade 0 and 3 second on the timer.

This time I used f/8 instead of f/5.6 and left the enlarger on 2x2 slide/645 mode as well, a slide is still a 35mm negative.

used contrast setting for grade 2, 0-0-0, and 7 seconds on the timer. Expected a sheet of black.. i got a beautiful image. whites were white, even in the back ground. I had detail on the wood panelling that before just had smudged lines on it. I had actual detail in a plaid shirt, actual detail, when before it was just lighter squares with blackness.

But i did have vignetting in one corner... SO i think its safe to say the lens is NOT meant for big enlargements. Or for going past something that fits onto an 8x10 sheet of paper without a good border line.

 

[koraks]

should i expect to NEED a change in contrast setting or aperture between the two?

Not every negative on a typical roll of film will have the same contrast. It all depends on lighting conditions etc. So yeah, it's perfectly reasonable that different negatives from the same roll ask for different contrast. Aperture, not so much. That's not negative-specific.

But i did have vignetting in one corner... SO i think its safe to say the lens is NOT meant for big enlargements.

Well, a 50mm lens will typically not cover medium format, so it's indeed sensible that you get vignetting with a 50mm lens and a 6x4.5 negative. This will be present regardless of how large the enlargement is, but the effect may attract more attention the bigger the print is.

Overall sounds like you're making progress, no? That's good to hear!

 

[redbandit]

Besler 1:3.5 f/50 lens...

Not the greatest at all according to internet. Yeah... its not.

However the conundrum im having is that printing has been hell for me. I mean, churning out bad print after bad print.

THe 35mm print i did also had vignetting in one corner, so I am of the aasumption that the lens is at fault, as the standard 35mm negative marking height has NONE in it, but swapping the enlarger height to 6x6, 645, 2x2 slide mode has vignetting in image.



But what i do not understand is how changing the enlarger height setting from 35mm negative mode to 2x2 slide has changed the results so much for me.

 

[Steve906]

The "enlarger height setting" when talking about negative mode is actually the condenser height. Moving it away from the negative makes it possible to illuminate a larger negative but the light is more spread out so needs a larger (size) aperture or longer exposure. Moving it closer such as for 35mm makes it brighter - same light over a smaller area , and enables smaller (size) aperture or shorter exposure and leads to less stray light reflecting around everywhere inside the negative carrier.

The 50 mm lens is unlikely to 'see' / cover a full 2x2 negative.

Raising the whole enlarger height to make a bigger print will also reduce the light reaching the paper, again, same light over bigger area needing larger (size) aperture or longer exposure.

Try changing just one thing at a time until its clear the effect it has then move on to another if needed.

I would tend to leave the aperture two stops closed from it's wide position and change time only for a start, then close the aperture 1 stop if times are too short on your normal size print, maybe aim for 10 to 15 seconds?

Of course others will say differently and these are really rough starting points to try and get at least some more satisfying results.

Steve.

 

[aparat]

You are probably not going to like my advice, but here it is. This type of calculation is best done "by the numbers," rather than trying to figure it out by using enlarger height, lens aperture, etc. The best way to do this, in my opinion, is to first test your paper (there are a few paper testing models around) and get yourself a darkroom exposure meter, such as the Ilford EM10 or, better yet, the Darkroom Automation Precision Enlarging Meter. Then, you can very easily look up all the adjustments you need when you change your enlarger height, filtration, lens, easel, and any other parameter that influences exposure and paper contrast. This can be done with a conventional timer or an f-stop timer.

To do a paper test, you do not need a densitometer. There's a very simple visual method involving making your own paper test strip (a kind of paper step tablet for each paper grade, if you will). The initial investment (a few hours of work and a few sheets of paper) will pay off because you will never have to guesstimate anything. It will just be a matter of looking up the needed exposure and filtration whenever you change any of the variables.

 

[Ian C]

The Beseler 50 mm f/3.5 is a decent quality triplet enlarging lens (3 air-spaced glass elements). It properly covers the 35 mm and smaller formats. The contrast is slightly less than with more-expensive 6-element lenses. In black-and-white printing, the contrast difference is easily eliminated by choosing a filter 1/2 contrast grade harder than I’d use with an EL Nikkor, for example.

I’ve made decent prints with mine from 8” x 10” up to 16” x 20” from 35 mm negatives. I got the best results at f/8. I don’t recommend using a larger aperture with this lens. If you need greater exposure, simply increase the exposure time.

Every negative is unique. Frames from the same roll, especially those shot under different lighting, will require a particular contrast filter for best results.

With any enlarging lens, you’ll get uniformly focused projections with the negative restrained in a glass carrier. Without a glass carrier, the image can go out of focus due to the upward expansion of the heated negative. The poor focus can occur over the entire frame or only in some areas. That is often wrongly attributed to a “cheap” or "defective" enlarging lens when the real problem is a heat-popped negative.

If you have the condenser unit installed, as I do on my 23CII with the Dual Dichro-S color head, you can get dark corners in the projection if the condenser unit is the wrong distance from the negative stage. The condenser unit of the Beseler 23C enlargers must be focused to give the most uniform light for the format in use.

That’s marked on the condenser stage adjustment. This is adjusted with knob #12 on page 1 in the manual in the following link.

http://www.jollinger.com/photo/cam-coll/manuals/enlargers/beseler/Beseler_23C_II.pdf

The negative size indicator (#13 on page 1) is a good starting point. But you might need to violate that somewhat for the most even illumination. On my 23CII, I get the best results by first composing and focusing the image, then removing the negative from the carrier and putting the carrier back in place.

With an upside-down scrap print on the easel, adjust the projected white light for the most even illumination. This is easily judged by observing the light on the white surface of the scrap print. This sometimes requires a slightly different condenser height setting than given on the indicator scale. Now reinstall the negative and fine-tune the focus. You should get a uniformly-illuminated projection.

 

[redbandit]

primitive multiqoute..

2x2 mode is for 6x6, 645, and 35mm slide.. I have a feeling that if the enlarger is designed to do a quality print at this distance for a 35mm negative slide, the same sized 35mm negative should be fine at this condenser height adjustment level.

Funny thing is, i was getting alot of lecturing that i should get ND filters, etc to use so that I could get exposure times longer then the 3 seconds i was needing to keep some detail in images.

the light meter from ilford seems nice, the dark room automation product seems nice BUT that one mentions its only "configured" for certain makes of paper. And its paperwork is all Fiber Based and Ilford products and i believe from memory, the more expensive Berger offerings.

I know the adjustment between condenser height for the 35mm and smaller negatives, and the 645/6x6/2x2 slide settings HAS to be the reason why things have improved.

 

[wiltw]

When you change enlargement size on easel, one would think that 'double the size = 4x the exposure'...but this is not necessarily true! Exposure reciprocity failure can have an effect upon times.

Here is a photo of a Kodak Darkroom Data Guide calculator. I put the base time at 5sec (assuming 2X) at the starting size...note what happens at 4X enlargement, then at 8X enlargement, then at 16X the starting size.

 

[redbandit]

When you change enlargement size on easel, one would think that 'double the size = 4x the exposure'...but this is not necessarily true! Exposure reciprocity failure can have an effect upon times.

Here is a photo of a Kodak Darkroom Data Guide calculator. I put the base time at 5sec at the starting size...note what happens at 4X enlargement, then at 8X enlargement

If you enlarge the image size upon the easel to say 16x20, put an 8x10 paper on the spot you want enlarged..
Does one really worry about the change in exposure time?

Just because the projected image size went from being a puny 7x8 to a beastly 16x20, does it actually mean i should be redoing test strips to figure out a new exposure time to that scale reading..

 

[ic-racer]

Changing the size of the image upon the easel and its impacts upon the lens aperture

Changing the size of the image changes the magnification which, in turn, changes the effective aperture based on the following equation:

Effective Aperture = Aperture Number on lens * (1 + Magnification)

This is why, when you change magnification, the exposure does not follow the inverse square law exactly (because your aperture changes without touching the lens).

 

[wiltw]

Changing the size of the image changes the magnification which, in turn, changes the effective aperture based on the following equation:

Effective Aperture = Aperture Number on lens * (1 + Magnification)

This is why, when you change magnification, the exposure does not follow the inverse square law exactly (because your aperture changes without touching the lens).

To be clear, and not confuse the OP...the aperture does not change...it is the exposure that changes, as illustrated by the photo of the Kodak Darkroom Dataguide, due to reciprocity effect. The equation provided by ic-racer computes that offset (which is not a 'smaller aperture' but a computation of adjusted time -- stated as if the aperture got smaller)

 

[xkaes]

Whatever enlarging lens is being used, it has one best aperture setting -- for best resolution, minimal light fall-off, least diffraction, aberrations, etc -- just like any taking lens. You can deviate from it, if you need to, but the farther the deviation, the less the resolution, more light fall-off, more diffraction, etc. For most lenses, the best setting is about 2 f-stop DOWN from wide open -- but it's E-Z to test for yourself.

The factor to vary is the TIME -- (which, of course, varies with the magnification).

But you have to use a lens that covers whatever format is involved.

 

[ic-racer]

To be clear, and not confuse the OP...the aperture does not change...it is the exposure that changes, as illustrated by the photo of the Kodak Darkroom Dataguide, due to reciprocity effect. The equation provided by ic-racer computes that offset (which is not a 'smaller aperture' but a computation of adjusted time -- stated as if the aperture got smaller)

The aperture size does not change, the EFFECTIVE APERTURE changes. The EFFECTIVE APERTURE determines how much light goes through the lens and is a physical property of any lens/aperture system. Nothing to do with light sensitive material or reciprocity.

When is this physically observed? Not when the column is raised as that maneuver lowers intensity only based on inverse square law. But once the lens is cranked back to focus, the EFFECTIVE APERTURE is smaller because the aperture is smaller with respect to the diverging beam of light as the aperture gets closer to the negative. This phenomenon is accounted for by the popular equation in post #11 above.

For those that are interested in more detail, diffraction follows the EFFECTIVE aperture. This is why high magnification with small lenses is not possible with visible light. That is why the electron microscope was invented.

 

[wiltw]

Changing the size of the image changes the magnification which, in turn, changes the effective aperture based on the following equation:

Effective Aperture = Aperture Number on lens * (1 + Magnification)

This is why, when you change magnification, the exposure does not follow the inverse square law exactly (because your aperture changes without touching the lens).

The aperture size does not change, the EFFECTIVE APERTURE changes. The EFFECTIVE APERTURE determines how much light goes through the lens and is a physical property of any lens/aperture system. Nothing to do with light sensitive material or reciprocity.

When is this physically observed? Not when the column is raised as that maneuver lowers intensity only based on inverse square law. But once the lens is cranked back to focus, the EFFECTIVE APERTURE is smaller because the aperture is smaller with respect to the diverging beam of light as the aperture gets closer to the negative. This phenomenon is accounted for by the popular equation in post #11 above.

For those that are interested in more detail, diffraction follows the EFFECTIVE aperture. This is why high magnification with small lenses is not possible with visible light. That is why the electron microscope was invented.

There is no such thing as 'effective aperture'...if you move a small light source away from a wall, its intensity drops simply because the light puts out a fixed quanitify of photos, and as you move the source away from the wall, the number of photos per square inch of wall declines...i.e. the light falllin on the wall is dimmer, yet there is NO APERTURE involved in this phenomenon (a small light source illuminating a scene).

Similar to what was described in the first paragraph there are a fixed number of photons coming thru the lens to the easel, as as you move the negative up farther from the easel, the image on the easel becomes larger and larger and the number of photos per square inch of paper declines, and the light become dimmer and needs a longer amount of time for the 'same exposure' to result. The aperture does not have a role when the f/number of the lens has not changed, merely the light is spread over a larger area, result in less photons per square inch of paper.

The 'effective aperture' in enlarging or in macro photography is merely an analogy for the decreasing amount of light falling on the easel per square inth or on the film plane (per square millimeter)...it is 'as if the aperture had changed' although there is truly zero change in the amount of light coming thru the aperture...it is the size of the area upon which the light is spread, which is what is truly changing. And, as the Kodak calculator clearly states, the progression is not 2...4...8...16 as area is doubled, but about 2...5.5...17.7 due to "compensation for reciprocity" as clearly printed by Kodak on their calculator shown in your quote in Post 10 (yes I changed the illustration which I used in post 9 because it had a broader scale of times, it nevertheless is from a Kodak Darkroom Dataguide of later vintage).

 

[ic-racer]

The effective aperture changes when the aperture position changes with respect to the source or target. This occurs during focusing and is independent of any 'inverse square' effect of on the spreading photons. It is a mechanical effect of a smaller aperture for the light through which to pass as the physical aperture approaches the negative when focusing a high magnification image.

Some more info here if not clear:

To satisfy the inverse square law with increasing magnification, the lens needs to be opened up to keep the same effective aperture, otherwise the image is dimmer than predicted by inverse square alone.

 

[Steve906]

primitive multiqoute..

2x2 mode is for 6x6, 645, and 35mm slide.. I have a feeling that if the enlarger is designed to do a quality print at this distance for a 35mm negative slide, the same sized 35mm negative should be fine at this condenser height adjustment level.

Funny thing is, i was getting alot of lecturing that i should get ND filters, etc to use so that I could get exposure times longer then the 3 seconds i was needing to keep some detail in images.

the light meter from ilford seems nice, the dark room automation product seems nice BUT that one mentions its only "configured" for certain makes of paper. And its paperwork is all Fiber Based and Ilford products and i believe from memory, the more expensive Berger offerings.

I know the adjustment between condenser height for the 35mm and smaller negatives, and the 645/6x6/2x2 slide settings HAS to be the reason why things have improved.

I think the fact that the negative 'carrier' is 2"x2" for mounted slides is possibly confusing. the condenser position should still be at 35mm position for mounted 35mm slides. A different negative carrier is required for each film size to hold it flat properly.
I did not see any lecturing on ND filters. but I'm sure people are mainly just trying to help. I personally have never owned or used one! and I have done many prints in the last 50 years.

 

[Nicholas Lindan]

...the dark room automation product seems nice BUT that one mentions its only "configured" for certain makes of paper...

No, the Darkroom Automation meter is not "configured" for specific papers. It can be used with any paper you wish.

 

[MTGseattle]

Lets back up for one minute. I apologize if this has been covered or is obvious, but I missed it, and I haven't had my hands on a 23c in a long time.
A 23c___ with a Dichroic head does it still use a glass condenser, or is there now a mixing box involved? Due to the OP statements, it sounds like the condenser is still shifted for each film size change.

Someone caught it above, but 35mm negatives print with the condenser in the 35mm position, not in the slide/6x6/645 position.

Also as stated above, the 50mm lens regardless of manufacture is going to be a bugger to print 645 with.

 

[redbandit]

Lets back up for one minute. I apologize if this has been covered or is obvious, but I missed it, and I haven't had my hands on a 23c in a long time.
A 23c___ with a Dichroic head does it still use a glass condenser, or is there now a mixing box involved? Due to the OP statements, it sounds like the condenser is still shifted for each film size change.

Someone caught it above, but 35mm negatives print with the condenser in the 35mm position, not in the slide/6x6/645 position.

Also as stated above, the 50mm lens regardless of manufacture is going to be a bugger to print 645 with.

the dichro S head has a light bulb and dichroic filter set. And an onboard power stabilizer and cooling fan for the light bulb.

The enlarger body itself still holds the condenser lens.

The thingy is, i have been using the enlarger at the "correct" setting for 8/16/35mm and 110 formats the book says to use, and what you guys say to use.

I moved the machine to the "2x2" slide/6x6/645 setting to do some 645 negative fun.

I left it on that setting and slid the 35mm negative of the people eating pizza in the dining room. Previously at the CORRECT 35mm negative setting..

One person is wearing plaid shirt... at correct setting one can barely make out its a plaid shirt. On the 645 setting i get detail..

Even the white plates are actually white now...

 

[Rick A]

Begs the question are the condensers installed properly? I used to have several of these enlargers with Dual Dichro S heads and the instruction manual is correct for the settings. Either something is installed improperly with your enlarger or you are doing something wrong (there's vignetting in a corner). The condenser settings should only be used when you have the condenser lamp house installed. If your prints are too dark you are giving too much exposure, a function of time and/or aperture setting. The sweet spot for your lens should be f8 or f11, and you adjust the amount of exposure time accordingly. Never expose with lens wide open. You need to understand, exposure time is how long you expose the print to obtain the whitest highlights without losing detail (D-Min), and blacks(D-max) is a result of contrast settings. The trick is to find the most pleasing balance between them. Not every photo contains the full range of tones from white to black, some are nearly entirely mid tones.