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henpe
7-Oct-2018, 02:30
Dear all,

I just want to share my latest findings on the difference, if any, in quality between my MF and LF work.

During last couple of years I have almost exclusively been using my 4x5 LF camera when getting out for landscape photography and I am now approaching approx 100 exposed sheets. Its great fun using the camera and I enjoy learning how to use tilts etc for creative purposes. I print my negatives in the darkroom, most often to 9.5x12" or 12x16".

Last darkroom session, however, I decided to print some negatives from my archive that were taken with my Pentax 67ii 6x7 MF camera. I was struck by the technical quality of these prints (I guess I have forgotten about this). In terms of "crispiness" and perceived sharpness, the MF negatives is even "better" compared to the 4x5" LF negatives I have been producing lately. Interesting, I think! However, it is not that my LF prints are "blurry" and I still consider them as "sharp". It is just that they lack a certain "edge" that my MF prints do show...

My MF equipment include:
Body: Pentax 67ii
Lenses: Pentax SMC 67 55mm / Pentax SMC 67 90mm / Pentax SMC 67 200mm

My LF equipment consist of:
Camera: Wista Field 45DX (wooden field camera, 4x5").
Lenses: Schneider Symmar-S 135 / Fujinon SW 90 / Fujinon NWS 210

For both setups, I use the same tripod (Berlebach Reporter, wooden tripod), same film (FP4+ and HP5+), same developer (D76), same "approach" to exposure etc. I have made tests with my LF to verify that the ground-glass is in correct position (made an exposure on a slanted ruler to verify focus plane as seen on GC matches with exposed image)

I use a Durst Laborator 1200, with Schneider Componon-s 150mm, for printing LF. I use my LPL MX6700 with a Nikon lens for printing MF.

Altogether, I think that my equipment for both LF and MF camera work are of good quality; I am not trying to compare apples with oranges, am I?

So, I am now trying to figure out why I can observe this difference in quality (in favor to MF). Is it simply so that my LF lenses render images differently, with less micro-contrast etc? Is it flare that makes my LF negs look less crisp? Is it so that my Pentax lenses are actually very sharp and outperforms more dated (?) LF lens designs? Is it perhaps so that my wooden field camera is less sturdy and take up vibrations more easily? Is it me !? Something else?

With this post, I do not wish to start up a heated vs. debate. I am happy with both my MF and LF equipment and will keep using both. I found it interesting that my findings are somewhat contradictory to common sense and what I would have expected. I am also curious if anyone else have similar, or opposite, experiences!


Best regards
Henrik



PS: I would like to attach some images to illustrate my points, but unfortunately I do not have a decent scanner that can reproduce the subtle differences I am trying to describe.

fotopfw
7-Oct-2018, 05:46
I worked for a long time with MF (Mamiya 6x7, 6x8) and LF (4x5" / 8x10"). In color (flatbed and drumscanned) the 4x5" outperforms the MF any time in my experience. Even the old Angulon on my 1950 or so Linhof Technika is very sharp, I can not match that with the MF. The way shadows open up is better in LF than MF. If I use Ektar in 4x5", that gives me enough contrast, detail and saturation, and again, not matched by MF. I compared large prints only (40x50").

Michael Roberts
7-Oct-2018, 06:03
As suggested by fotopfw, I think the reason the MF prints look a little more crisp is that you are only enlarging to 12x16. This is only about a 6x enlargement from the 6x7. The shorter fl length lenses will have a greater depth of field, which could translate to a crisper look in an enlargement of 6x or less. So, yes, I think you are comparing oranges to apples, especially if your are comparing a photo with a 55mm MF lens to one with a 135 or longer fl LF lens.

A better comparison would be to use your 90mm or 200/210mm lenses on both formats, then compare a 6x7 crop from 4x5 to the same size MF....

Liquid Artist
7-Oct-2018, 06:06
Just a couple things to consider.
It's tough to beat the quality of your Pentax lenses plus there is a good chance you where using a faster shutter speed. So therefore less motion blur.

gypsydog
7-Oct-2018, 06:26
Are using a grain magnifier to focus the enlarger? If so, even a slight increase in grain on the smaller negative can be easier to focus properly.

alexmuir
7-Oct-2018, 06:55
You could try enlarging an example of each format on the 4x5 enlarger, using the same lens, and to the same size. That would help ascertain whether or not the enlargement equipment is having an effect on quality. Your 4x5 enlarging set up should be producing quality results, but that doesn’t necessarily mean that it is achieving optimal quality.
Alex.


Sent from my iPhone using Tapatalk Pro

scheinfluger_77
7-Oct-2018, 07:26
Another possibility is the ground glass is slightly out of position compared to where the film plane is, with holder inserted. Shims or lack thereof behind the ground glass is where you could first start testing.

Bob Salomon
7-Oct-2018, 07:29
You could try enlarging an example of each format on the 4x5 enlarger, using the same lens, and to the same size. That would help ascertain whether or not the enlargement equipment is having an effect on quality. Your 4x5 enlarging set up should be producing quality results, but that doesn’t necessarily mean that it is achieving optimal quality.
Alex.


Sent from my iPhone using Tapatalk Pro

Except using the longer lens with mf will require more magnification which could be outside the optimal mag range of the lens. And the head would be much higher possibly increasing the possibility of vibrations.

faberryman
7-Oct-2018, 07:32
Perhaps the appearance of grain enhances the perception of sharpness.

Ken Lee
7-Oct-2018, 07:57
...I am not trying to compare apples with oranges, am I?

It might be helpful to rule out as many the variables as possible.

Shoot an unvarying subject from the same distance at the same time with both cameras. Use an aperture small enough to give decent depth of field but not enough to introduce diffraction. For example f/22 on the LF and f/11 on the MF.

Use plenty of light so that your shutter speed is high. Shoot at a distance and don't use any view camera movements so that you're shooting through the center of the LF lens and not running into issues of close-range performance or bellows compensation.

Choose a stationary subject which makes it easy to compare resolution. Angular light falling on a distant series of buildings is good, for example.

If possible, put an identifying card in the scene which makes it easy to tell which camera/lens was shot.

Develop both images at the same time if possible. I don't mean the same afternoon: I mean simultaneously in the same tank, tray or whatever you use.

Place a portion of both negatives in the enlarger's film carrier. Enlarge both negatives at the same time and first use the Componon. Then do the same with the Nikkor.

Alan9940
7-Oct-2018, 07:58
A couple of thoughts...

1) I'm not familiar with either of the enlargers you're using. What is the lightsource? An enlarger that beams light through a condenser lens will, generally, make prints looks "crisper" than, say, from a coldlight source or color head.

2) What is the focal length of the enlarger lens used for MF? Is it of the same quality as the Schneider 150mm used for 4x5?

3) What were the conditions under which the 4x5 negs were exposed? Wind? Camera movements?

4) What were the lighting conditions of the LF negs vs the MF negs?

You don't really have to answer...my point is that many, many variables can affect results. Here is what I'd suggest: photograph the same scene, under the same conditions, same film, similar FOV focal length lens (if you can), no movements of any kind on the LF camera, critical focus for both cameras, optimal aperture for both cameras (watch shutter speed with the LF camera because if things are moving, it will obviously affect results), process with the same film developer, then contact print on the same paper, filter, etc.

In other words, eliminate as many variables as possible and compare.

henpe
7-Oct-2018, 12:29
Thank you all for your inputs, much appreciated!

Sounds like a good idea to make comparative tests in which as many variables as possible have been eliminated/harmonized between the formats. First on my list will be to enlarge the same negative into both of my enlarges, since this is the easiest and quickest test to accomplish.

I will try to update this thread as soon as I have something new to present.

Again, thanks for all input!

Pere Casals
7-Oct-2018, 12:59
I print my negatives in the darkroom, most often to 9.5x12" or 12x16".

You need a print well exceding 20" or 30" to show the superior Image Quality that LF has over MF.

A 16" print from a MF 6x7cm negative may have Image Quality exceding what human eye can see, even when viewing it with the nose on it.




the MF negatives is even "better" compared to the 4x5" LF negatives I have been producing lately.

You probably have a problem in your LF process.

Make a side by side test, shot the same framing with MF and LF, with same film. Then check the Image Quality in the negative with a x30 magnifier or in a top quality digital scan.

If you don't notice a remarkable superior IQ in the 45 sheet then you have a problem in the taking: it can be the lens, the GG to film matching or your technique.


If you have better IQ in the 45 sheet but not in the print, then obviously you have a problem in the enlarging !!


...so IMHO in a 20" print you may not notice the superior IQ of the LF process, but if your print from LF is inferior to the MF case one... then you should make a side by side test to find where your problem is.


https://www.onlandscape.co.uk/2011/12/big-camera-comparison/

ottluuk
7-Oct-2018, 23:22
If you enlarge to equal print size from 6x7 and 4x5, you'll always be closer to showing the grain structure with 6x7. So the LF enlargement could appear smoother even if other parts of the workflow match very closely in terms of visual quality.

One way to bypass enlarger-related variables would be using a 6x7 roll film back on your 4x5 camera. If you can get a "crisp" print via LF lens + roll film back + 6x7 enlarger, you need to look at the LF enlarging part of your process. If not, it's likely the taking lens.

Another way would be to make a sacrificial test negative in 4x5 and print it at a known ratio on the Durst. Then carefully cut the neg to fit your 6x7 carrier and print this section on the LPL at the same enlargement ratio. Compare the prints feature by feature.

joem
7-Oct-2018, 23:32
So let me get in trouble again, first have to don my armor and get the shield ready.
Way back when i had a Pentax Spotmatic at some point i sold it and went with Topcons (super D) with lenses for each to have two types of film ready. The images from the Pentax were always sharper and contrastier regardless of film type or processing and i think that you'll find this in the end the MF just has a better lens period.
j

Pere Casals
8-Oct-2018, 01:35
If you enlarge to equal print size from 6x7 and 4x5, you'll always be closer to showing the grain structure with 6x7.

Yes, but depending on film and developer, TMX vs HP5. TMX with stock Xtol in 6x7 may show less grain than HP5+ with Rodinal in 4x5...





One way to bypass enlarger-related variables would be using a 6x7 roll film back on your 4x5 camera. If you can get a "crisp" print via LF lens + roll film back + 6x7 enlarger, you need to look at the LF enlarging part of your process. If not, it's likely the taking lens.

Another way would be to make a sacrificial test negative in 4x5 and print it at a known ratio on the Durst. Then carefully cut the neg to fit your 6x7 carrier and print this section on the LPL at the same enlargement ratio. Compare the prints feature by feature.

These are tests that can deliver important information, but we cannot do a direct comparison. MF lenses may deliver more optical performance than LF lenses, at least it's easier to make a better lens for the smaller format... but in the LF case we anyway may obtain better Image Quality (with a lower lp/mm lens) from the larger surface.

Because of that we should not compare at "the same enlargement ratio". We should frame (aprox, because of aspect ratio) the same in the MF vs LF shots, and then taking an equal crop of the scene from both negatives, and enlarging to the same final size. In that situation we'll need to use different enlarging lenses or the same in different conditions... so anyway we need understanding what we are doing.

If we compare results with the same enlargement ratio then MF has an advantage, at least in theory...

GG12
8-Oct-2018, 04:17
Its not clear if its a) the overall image that is less "crisp" or b) there is no point in the 4x5 neg which is as sharp as the MF.

To answer this.... consider shooting a tape run going from 6'-12' away from you with both setups. Focus on the same spot, and compare. If there is no place on the LF neg that is sharp, that will tell you one thing. It may be that the focus set up (GG to film back) is off, and that the focus point is shifting. Of course, this is a supplement to all the other excellent recommendations already given.

Willie
8-Oct-2018, 08:45
How is your tripod? What may be very stable with the medium format may be a touch shaky with the heavier outfit.

fj55mike
8-Oct-2018, 13:10
Perhaps the appearance of grain enhances the perception of sharpness.

I agree with this assessment, and notice it especially with HP5+ and Tri-X in medium format. They appear very sharp compared to 4x5 HP5 on the same sized papers.

Bernice Loui
8-Oct-2018, 14:27
Many factors can cause a sheet film image to be less "sharp" or "Crisp" than a medium format film image.

*Taking aperture, at apertures smaller than f32, image quality is likely to suffer.

*Camera alignment- precision- stability, any can and will affect image quality on film.

*Tripod stability or camera support stability and transmission of vibrations due to the camera support system.

*Film flatness, MF cameras often have significant mechanical designs to assure the roll film is as flat as possible.
Film holders can have significant variations in actual film flatness and alignment- registration to the view camera's ground glass.

* Problem with the view camera lens, test and verify the lens being used meets it's design specifications.

As for testing image quality, use a GOOD high quality microscope to examine the image on film. This takes out the potential problems with the optical printing process. Having used film formats from 35mm to 8x10, the sheet film images are constant and consistently better than roll film. This has held true for Hasselblad 6x6 to 6x9 Arca Swiss to 6x9 Fuji Texas Leica to Mamiya 6 & 7.. Sheet film when properly results in better overall image quality.

When the entire camera to printed image system is all proper, differences between a B&W 2x sheet film (5"x7") print compared to a 5x medium format film (6cm x 7cm) image is quite apparent. It does not require a HUGE enlargement to resolve and visualize this difference.


Bernice.

ic-racer
8-Oct-2018, 15:25
It is just that they lack a certain "edge" that my MF prints do show...

Something is not right. Seems like an issue worthwhile to explore. In my darkroom, the only way I can tolerate 6x6 anymore is to print them to the same magnification as I print 4x5in. That is make the 6x6cm prints around 2-3x magnification.

Bernice Loui
8-Oct-2018, 16:46
3X is about as much as I'll tolerate for 5x7 B&W sheet film. Mostly stopped using B&W roll film for this reason. Only 120 roll film camera around these days the 6x9 Arca Swiss + lenses and etc and that is a not often used camera. The image quality is just not there. Image quality is far beyond "Crisp" or "Sharp" there are a good number of factors far beyond crisp and sharp that sheet film will produce that simply does not happen on roll film.


Bernice



Something is not right. Seems like an issue worthwhile to explore. In my darkroom, the only way I can tolerate 6x6 anymore is to print them to the same magnification as I print 4x5in. That is make the 6x6cm prints around 2-3x magnification.

jim10219
9-Oct-2018, 11:17
Many factors can cause a sheet film image to be less "sharp" or "Crisp" than a medium format film image.

*Taking aperture, at apertures smaller than f32, image quality is likely to suffer.

*Camera alignment- precision- stability, any can and will affect image quality on film.

*Tripod stability or camera support stability and transmission of vibrations due to the camera support system.

*Film flatness, MF cameras often have significant mechanical designs to assure the roll film is as flat as possible.
Film holders can have significant variations in actual film flatness and alignment- registration to the view camera's ground glass.

* Problem with the view camera lens, test and verify the lens being used meets it's design specifications.

As for testing image quality, use a GOOD high quality microscope to examine the image on film. This takes out the potential problems with the optical printing process. Having used film formats from 35mm to 8x10, the sheet film images are constant and consistently better than roll film. This has held true for Hasselblad 6x6 to 6x9 Arca Swiss to 6x9 Fuji Texas Leica to Mamiya 6 & 7.. Sheet film when properly results in better overall image quality.

When the entire camera to printed image system is all proper, differences between a B&W 2x sheet film (5"x7") print compared to a 5x medium format film (6cm x 7cm) image is quite apparent. It does not require a HUGE enlargement to resolve and visualize this difference.


Bernice.
That's mainly what I would suggest. Make sure the tripod is equally capable of holding both cameras steady. LF cameras tend to be a bit heavier (though some MF cameras can give a lightweight LF camera a run for it's money). Also, you're enlarging with a different lens. That Componon enlarging lens may not be as good as your others. Try using the same lens on both formats and see if the difference remains. If you're stopping down a lot in the field, you may have diffraction issues. Sometimes the appearance of grain can make an image appear sharper, versus a nearly grain-less image. Also, it's harder to properly focus a large format negative on an enlarger due to the smaller perceived grain size. And probably the most likely answer is the negative is sagging in the image carrier. That's rarely a problem with 135 film and usually not a major issue with 120. With 4x5 and larger, it's almost always an issue you have to deal with. Really, the problem could be anywhere. But it definitely sounds like you're having a problem.

Pentax makes some great lenses. So I wouldn't be surprised to hear that if you compared one square inch of your MF film taken with that camera to one square inch of you LF film that you wouldn't see a sharper image. However, if you compare the entire 6x7cm image to the entire 4x5, the 4x5 film, even with a pretty mediocre lens, should produce a significantly sharper image.

Peter De Smidt
9-Oct-2018, 11:27
Ground glass not being in the optimum position can also be a problem.

Pere Casals
9-Oct-2018, 11:55
Ground glass not being in the optimum position can also be a problem.

The wista has a fresnel in the inner side of the GG, I think.

If IIRC with cameras having a fresnel in the inner side, if the GG is broken and replaced by a regular GG not having the same fresnel inside... then the GG to film plane matching won't work until adjusted for the new situation.

Bob Salomon
9-Oct-2018, 12:27
The wista has a fresnel in the inner side of the GG, I think.

If IIRC with cameras having a fresnel in the inner side, if the GG is broken and replaced by a regular GG not having the same fresnel inside... then the GG to film plane matching won't work until adjusted for the new situation.

If the fresnel remains in place and all you do is change the gg then no adjustment is necessary as the ground side will still be facing the lens.

If a fresnel under the gg is replaced, and it is thicker or thinner then the original one then adjustment would have to be made.

If an inside fresnel is moved to the topside of a gg then adjustment is necessary.

Drew Wiley
9-Oct-2018, 13:11
I have many years of experience with the P67 system, including their very sharpest lenses. Even garden-variety 4x5 should beat it hands-down per print detail and tonality any day of the week. Don't know what to say... Check alignment of your enlarger carriers. I hate fresnels on view cameras, period, so never have an issue with them. Get rid of it and see what happens.

Pere Casals
10-Oct-2018, 06:49
If the fresnel remains in place and all you do is change the gg then no adjustment is necessary as the ground side will still be facing the lens.

If a fresnel under the gg is replaced, and it is thicker or thinner then the original one then adjustment would have to be made.

If an inside fresnel is moved to the topside of a gg then adjustment is necessary.

Thanks for making it clear

Bernice Loui
10-Oct-2018, 07:03
Ditch the Fresnel as a GG viewing aid. Each and every one of them tried over decades has been nothing but problems and more problems.

Fresnel on the GG can cause double images with a wide angle lens, the grooves regardless of how small they are affect the ability to focus, can cause focusing errors and...

Best is regular ground glass with the finest grit available-possible.


Check the distance from the film holder to GG (adding a Fresnel add another variable), make absolute sure there is no more than a few thousands of an inch tolerance between seated film holder film plane to GG across the entire film holder film seating area. If the film holder and camera cannot hold this tolerance, there can easily be problems like lack of sharpness-definition and related.


Bernice

Pere Casals
10-Oct-2018, 09:42
Ditch the Fresnel as a GG viewing aid.

One should not simply remove a fresnel mounted in the inner side, after that one has to calibrate again the GG to film plane matching, as Bob just explained.

At Wista manufacturing they were not rookies, they made a perfect installation of the fresnel and that worked pretty fine, of course one may not want the fresnel but, as said, if the back is not adjusted after it... then we have a trouble...

A fresnel in the outer side can be removed with no necessary additional calibration.

Luis-F-S
10-Oct-2018, 09:42
Ditch the Fresnel as a GG viewing aid. Each and every one of them tried over decades has been nothing but problems and more problems........

Bernice

Never ceases to amaze me how people go out of their way to muck things up, and then wonder why it doesn't work! L

henpe
11-Oct-2018, 11:38
Sorry for my silence; been too busy the latest couple of days.

Just to clarify. I did a test to verify that the GG vs film-plane distance is ok. For that purpose I built a test-rig, see below

183242

I used a piece of sheet aluminium onto which I glued a high-contrast target. There is also a "ruler" that is slanted by 45 degrees in the z-direction (= optical axis). The zero mark on the ruler is aligned with the aluminum plate (not very clear in this image, but they are). I set-up my camera an focused on the plate/zero mark, using a very sturdy tripod and a focusing loupe (and of course the GG+fresenel combo (Wista original by the way)). After exposure, I verified that the focus was still spot on. Attached below is a close up on the resulting sheet-film negative.

183243

It is a quite lousy scan, but as far as I can tell, the focus is pretty spot on, right? I don't think I have a problem with GG alignment!

Next-up to test is my enlarger setup...


By the way, how to verify that the taking lens of the camera is properly assembled in terms of disance between front- and back- module?

Pere Casals
11-Oct-2018, 15:36
By the way, how to verify that the taking lens of the camera is properly assembled in terms of disance between front- and back- module?

You can print a USAF 1951 resolution target (http://www.takinami.com/yoshihiko/photo/lens_test/USAF.pdf) and evaluate the optical performance of your glass. Your lenses (Schneider Symmar-S 135 / Fujinon SW 90 / Fujinon NWS 210) should yield around 50 to 70 Lp/mm, with comparable results like here: http://www.hevanet.com/cperez/testing.html

henpe
27-Oct-2018, 13:31
A short follow-up.

I have not tested my taking lenses yet, but I did run a few tests on my enlargers and found some interesting results.
I was able to acquire a transparency USAF 1951 resolution target. I put the target in both of my enlargers and made prints with both my Nikon 80mm and my Schneider Componon-S 150mm. In all tests, I printed the target to x5 times magnification. When inspecting the prints with a loupe, I found that prints made with my Durst L1200+CLS450 are less sharp compared to prints made on the LPL. This is down to the very fine details of the resolution target. When looking with my naked eye, I cannot spot a difference. I suspect the difference is due to the fact that the LPL is fan-less, while the Durst is not....

Jac@stafford.net
27-Oct-2018, 13:42
Quick question - do you examine the image on the base board (with sample of paper bemeath) using a grain focus device, and if you do, what brand/model number of the device? Thank you.

henpe
27-Oct-2018, 13:50
I made prints on RC paper and then inspected the prints using my eye, but also with a x40 stereo-loupe. When focusing the enlargers, I used both my Peak and my Bestwell Optics Micro-Sight (they both agree with each other, it turned out). I must admit though that obtaining critical focus was a bit tricky.

Next time in my darkroom, I will make new test prints with the Durst but with the fan temporarily disconnected and see if there is a difference....

Pere Casals
27-Oct-2018, 14:52
I made prints on RC paper and then inspected the prints using my eye, but also with a x40 stereo-loupe.

To evaluate ultimate resolving power you have to ensure paper flatness. You can place a piece of glass on the easel sprayed with 3M Re Mount glue, this should ensure paper flatness. To test the corners you also have to ensure a perfect alignment, and/or focusing again for the corner.

LabRat
27-Oct-2018, 16:04
There's other factors to examine too, like if the film is popping in the neg carrier during exposure, as mentioned paper flatness, easel or other movement issues, is your grain magnifier really right on, etc... Or maybe something about you like not wearing your glasses with your magnifier setting, or not seeing the grain clearly, as it is different looking from smaller formats... And really go over your enlarger settings if something is not set right...

I have also seen on some enlargers when the bellows are extended that they create a pull that changes the focus settings sooner or later, or other locks that drift...

Test, test, test...

Good luck!!!

Steve K

interneg
27-Oct-2018, 16:46
I made prints on RC paper and then inspected the prints using my eye, but also with a x40 stereo-loupe. When focusing the enlargers, I used both my Peak and my Bestwell Optics Micro-Sight (they both agree with each other, it turned out). I must admit though that obtaining critical focus was a bit tricky.

Next time in my darkroom, I will make new test prints with the Durst but with the fan temporarily disconnected and see if there is a difference....

The Durst column should really be braced to a solid wall, otherwise you've got a big inverted pendulum wobbling around. May make a significant difference in sharpness, more than any lens.

Jac@stafford.net
27-Oct-2018, 16:51
I made prints on RC paper and then inspected the prints using my eye, but also with a x40 stereo-loupe. When focusing the enlargers, I used both my Peak and my Bestwell Optics Micro-Sight (they both agree with each other, it turned out). I must admit though that obtaining critical focus was a bit tricky.

Did you or not place a piece of enlarging paper under your Peak?
After using a focusing device properly do you change aperture? (Do not do that)
Finally, just how accurate is your stereo-loupe?

Bernice Loui
28-Oct-2018, 08:53
Enlarger check list:

*Absolute alignment between enlarge head to base board. This is a must and cannot deviated by more than fractions of a mm over the entire travel distance of enlarger head to base board. The planes between enlarger head film holder to base board must be absolutely parallel at all times.

*Enlarger stability. The table supporting this enlarger absolutely rigid and stable? The enlarger column properly supported? Much the same as a flimsy tripod trying to support a view camera vibrations and more is easily transmitted to the optical printing system causing out of focus or appearance of problem like this. This is also why the preference to a floor standing enlarger, the entire enlarger-projection system tends to moves together as a unit which helps negate some of the potential vibration problems.

*Flatness of paper holding easel. If the easel holding the paper to be projected on is not flat some areas will be out of focus.

*Longer enlarging times can help reduce the effects of vibration. This is much the same technique used by the microscope photographer folks. By allowing the projected image information to integrate over time on the projected media, it can help negate some of the vibration problems. Consider using a print time of 20 to 40 seconds.

*Wrong condenser set for a given enlarger lens focal length if a condenser enlarger is used. This can result in light fall off at the edges of the print to poor optical performance of the light source to projected image to the print. The light source must be properly aligned to the condenser systems and enlarger lens. If a diffusion enlarger is used, this does not matter. Based on experience with both condenser and diffusion enlargers, the condenser enlargers when properly set up with the very best enlarging lens can project more optical information on to the printing paper that can be resolved-presented in the finished print.

*Projecting the image to print paper using the near optimal aperture of the enlarging lens. Typical good printing aperture of an enlarging lens is two stops down from full aperture. Avoid stopping down the aperture any more than needed beyond two stops from full aperture. There is no need and will only degrade the projected image. Better to adjust the exposure time to achieve lens projection aperture of about two stops down from full.

*Grain focuser working properly? Thickness of the print paper added when grain focuser is being used?


Bernice

tgtaylor
28-Oct-2018, 10:56
I use a glass carrier for all negatives - it's a PIA but it insures the negative is perfectly flat during printing. I use a laser to check the enlarger alignment for each negative once the correct printing height is determined and I begin ("pre-trip") each printing session by checking the alignment of the table and easel with a torpedo level, and the enlarger (front/back, right/left, negative stage) and the lens with a laser (you want the laser beam to bounce back from the lens into the target). I use Bess-Align lens-boards that allow lens tweaking.

Thomas

Eric Woodbury
28-Oct-2018, 12:42
I like the ground the glass idea (out of registration with plane of film holder). My 5x7 Deardorff was so far off when I bought it (new) that it was ridiculous. I re-machined the back to fix.

Compare equal focal lengths, same subject, same everything between the two. Eliminate the enlarger problem with contact printing. Contact printing has better local contrast and removes other issues of projection.

henpe
28-Oct-2018, 12:50
+ both enlargers wall-mounted, on the same wall and next to each other
+ class carrier in both enlargers (does not matter in this test since USAF target is on glass substrate)
0 No paper under grain focuser, when using neither of the enlargers, so we are consistent between tests.
+ Both enlargers should be properly aligned, but I dont think that matters here since I was only interested in a tiny spot of the projected image corresponding to the fine details/groups of the USAF target (I focused by using my grain focused on this spot).
+ I checked my stereo-loupe and it is good for at least 180 lp/mm, which should be sufficient for my needs.

I think I have ruled out most factors and that I am consistent in my testing. I suspect that tiny vibrations in my Durst cause small vibrations that distort the very fine details of the USAF-target when printed. I suspect this does not have a practical significance to print quality, but just out of curiosity I will try to compare prints from my Durst with and without the fan disconnected. I will report back in due course....

Jac@stafford.net
28-Oct-2018, 13:19
henpe, do you use a foot switch or some switch on the bench?

Bernice Loui
29-Oct-2018, 09:46
If the enlarger (s) are wall mounted, do they have any support for the base board? If not, they will effectively be a pendulum mounted on a drum head. Wall vibrations will be transmitted to the enlargers easily. Weight of the enlargers, rigidity of the mounting, wall rigidity and more all have an effect on the self resonate frequency and "Q". This will alter vibration behavior of each specific enlarger. Touch the enlarger, the entire set up can vibrate and remain vibrating for some duration of time.

Do apply a sheet of paper under the easel to compensate for thickness when focusing. It does make a difference.

Looking at a specific spot-area of enlarged interest is OK but to achieve overall print definition, the entire system must be precisely aligned and stable.

As for inspection-evaluation tools, a high quality microscope is the proper solution for both film and print.



Bernice




+ both enlargers wall-mounted, on the same wall and next to each other

0 No paper under grain focuser, when using neither of the enlargers, so we are consistent between tests.
+ Both enlargers should be properly aligned, but I dont think that matters here since I was only interested in a tiny spot of the projected image corresponding to the fine details/groups of the USAF target (I focused by using my grain focused on this spot).


I think I have ruled out most factors and that I am consistent in my testing. I suspect that tiny vibrations in my Durst cause small vibrations that distort the very fine details of the USAF-target when printed. I suspect this does not have a practical significance to print quality, but just out of curiosity I will try to compare prints from my Durst with and without the fan disconnected. I will report back in due course....

Cor
30-Oct-2018, 02:17
I took have a Durst L1200, and a CLS450 head, but I never got used to the CLS450, partly because it is me..I have been printing for ages with the condensors and MG flilters in the drawer between the light and the condensors, partly because of the noice of the head, partly because of the vibration of the fan (felt thevibration when puting my hand on the head)..I never realy looked into the vibration issue, just switched back to the head I am comofortable with, and live with swapping MG filtes (which If I work carefully is not needed that many times anyway)

Best,

Cor

John Layton
30-Oct-2018, 05:40
Hmmm...what hasn't yet been suggested...

OP...can you tell us what aperture settings you typically use for enlarging...for both MF and LF? (keeping in mind that the same potential for levels of unsharpness caused by diffraction exist for enlarging as for photographing)

Would it be possible for you to test another 150mm (LF) enlarging lens of known good quality?