Collimating light for more sharpness

Yes, thinking about it the iPad plus diffuser would be flat intensity across the surface but locally would be diffuse. It will be interesting to see the results of your condenser vs collimated tests.

Unless you just like to tinker, all these issues have been addressed commercially with devices such as the Essential Film Holder, a purpose-engineered device sold worldwide by Englishman, Andrew Clifforth:

andrew@clifforth.co.uk
https://clifforth.co.uk << about the EFH

I used every sort of lamphouse in the photo industry over the course of 50+ years, 33 in labs. Condenser enlargers are best when you want B&W to look gritty. Diffusion dichroic enlargers are best for color, and for B&W variable contrast printing papers. Cold light sources are the softest for B&W, but don’t work for color.

Ergo, I use the diffuser built into my EFH, which I mounted in a 10” by 15” sheet of half-inch railroad board (black foam core mounting board). I cut a window under the EFH and mounted a Viltrox L-116t LED panel there, using Velcro strips. I raised the board up on three sides with L-shapes made from scrap 1x2 maple, and connected an AC adapter.

My 50+ year old negatives from high school yearbook photography never looked this good on silver halide paper! The EFH keeps film FLAT.

I have the 35mm and 120/6x9 film guides on the EFH. If I take off the 35mm guide plates that mount over the 6x9 aperture guide, I can Velcro my 35mm and 6x6cm Omega B-22 negative carriers on there, to handle single cut negs, or strips too short for the EFH.

The Callier Effect occurs at the silver emulsion and the scattering is random. Using a camera to image the emulsion thus illuminated will not eliminate the effect; highlights will pass less light to the imaging medium (enlarging paper, digital camera) in a non-linear function. The Callier Effect from collimated light scatters light passing through silver emulsions, and has a more pronounced effect as the density of the silver increases. Thus denser areas (negative highlights) are effectively “held back;” in a print this effect is reversed, thus producing harsh highlights artificially too light. We used to develop our film to a lower gamma to compensate for the Callier Effect, which meant less graininess due to lower silver density, more important in small size film (35mm) than larger formats. But the effect on tonality is some
harshness, which we now think of as the 35mm film “look.” My advice is to go with a diffused, high CRI light source and add a little more sharpening in post processing if you think you need it; there are many and subtle ways to do this intelligently. BTW, you cannot get to a 1:1 copy of a 35mm film with the 100mm Macro Planar and a full frame Nikon camera. It’s a great lens but limited by design. Adding tubes or close up attachments gives noticeably poorer results. Watch out for Newton rings with your glass set-up. Keep experimenting.

Hi Burkphoto,

Thanks for the inputs and for sharing your extensive enlarger experience. Yes, I read about the EFH and considered purchasing it, but ended up putting something together quickly since it was easy and since I did want opalescent glass as a diffuser. I have to admit that indeed I’m a bit of a tinkerer :wink: and am now planning to place a slide holder inside my 5.5x5.5 cm window to enable also 35mm film in the same configuration.

Being of a certain age, I grew up with film, but to my regret now, I never embarked on developing or enlarging myself. Eventually, I purchased my first computer for the sole purpose of using it as a digital darkroom, but was always disappointed with scans of my negatives, whether I scanned them myself or sent them out to have it done. Then digital cameras got fancy and I never looked back, but kept on wondering why some folks kept talking about negatives as “real RAW”. Fast forward to now, when my D700 broke and Nikon suggested I throw it away because it was 10 years and therefore “old”, which seriously upset me since my old trusty F801 was still working as new. Since I had “matured” with digital I was looking for some new excitement, and now have two 70 year old film cameras (a Zeiss Ikon Super Ikonta for MF and a Contax iia for 35mm) that needed some overhaul but now seem to be working as new again. This triggered the desire to get proper scans and here we are.

I think you hit the nail on the head by your statement that your 50-year old scans never looked this good, and I was similarly amazed by how good DSLR scans looked in comparison to the crummy self- and commercial scans that I have of my film stock. Hence, film still rocks, and as a bonus one gets to play with some wonderful historical cameras.

I’m still not sure where I’ll land with respect to lighting for scanning, but the inputs here seem to converge to diffuse light as default, with collimated light with its Callier disadvantage for gritty B&W. Hence, there might be no single “best” solution for all purposes.

I do appreciate very much everyone’s inputs as I’m learning a lot as part of the exercise and that is great fun.

Cheers,

Arno

Hi Jeffstev,

Thanks for your inputs.

I think you’re correct and the Callier effect will also be present with DSLR scans, so what I currently have might suffice as a good solution, though I still would want a tungsten continues spectrum light source as opposed to a discrete one, even when it’s high CRI, just for peace of mind. It shouldn’t be too complicated to arrange that.

With regards to 1:1 with my 100mm Zeiss: yes, I’m aware. So far I did my 35mm with an old Nikon slide copy adapter that I had in a drawer for some 25 years or so, combined with a Nikon EL 50mm 2.8 enlarger lens that I used for macro since it should be optimized for field curvature:

The results were not (yet?) as good as the scans from my MF film though so I’ll keep experimenting. I do have some old manual macro rings and bellows to get the Zeiss to 1:1 will see how that works.

Cheers,

Arno

This series of images illustrates what happens when the diffuser is moved between the light source and the “negative”. Between the light source and the negative, I put a diffusor and moved it from close to the light to close to the negative while the distance between the light and the negative remained a constant 25 cm. The practical side of this setup is, that I can change the looks of the negatives by simply moving a diffuser…

The leftmost image still shows the matrix of white and yellow LEDs from the backlight. Moving the diffusor towards the negative increasingly reduced the grittiness of the resulting image - without sharpness per se. The shots at left might look sharper but it’s looks only and nothing that cannot be compensated for with Lightroom’s sliders.

Here’s a photo that shows the whole rig:

That is an interesting comparison. I wonder what’s going on optically there. If I understand well, then your “negative” is a ermmm “geodreieck” (triangular plastic ruler in English perhaps?) that has a thickness substantially larger than the emulsion side of a negative? It seems that placing the diffuser, i.e. light source further away creates some shadows from the backside of the ruler. It reminds me of portrait shooting: A larger and/or closer light source provides “softer”, or better diffused, light, without evoking loss of sharpness, but with less specular highlights and softening of details. I’m not sure how that compares to perfectly collimated versus perfectly diffused light?

I was lucky to work with Kodak technical service reps in the late 1990s, early 2000s, as they developed high speed, high resolution scanners. Their Bremson HR-500+ was the pinnacle. It was a $50,000 beast that could scan film up to 70mm wide and 100’ long. We had nine of them in our lab in 2003, and 12 more in our other three labs. They scanned each school portrait in four seconds. By 2007, they were obsolete and we had ripped out our film processors!

Those moved film between a 6002-pixel sensor bar and light source. The software, DP-2, was a giant imaging database and rendering engine that ran on a Microsoft SQL Server. I think we are very lucky to be using Negative Lab Pro, because it does a similar job as that setup, a LOT more easily.

The HR-500 light source was a Tungsten-halogen lamp. The scanner had to be re-calibrated after each lamp change, which was NOT a fun task, as it involved “slope” adjustments for over- and under-exposed films. It was also incapable of self-adjusting for different film emulsions. We standardized our business around Portra 160 film, so that took care of that issue…

Anyway, the only issue I see with Tungsten filaments is that they yellow and dim as they age. NLP should compensate for the color shift, since you white balance the film base in Lightroom Classic. But you may see a gradual exposure shift over time. If you’re like me, and expose everything based on the film base density plus fog = black, there will be a slight adjustment between lamps.

I’m using my Viltrox light source at 100% brightness, 4400K setting, which uses all the yellow and all the blue LEDs at roughly equal intensity. That seems to provide the best color response on slides and color negative films. With black-and-white, it doesn’t really matter.

Yes, it’s easy to get lost in the black hole of post-processing. With LrC/NLP and Ps, I can do more than I knew how to do in a darkroom. Exposures I could never figure out how to print are usable now.

A source of limited size emitting diffused light emits collimated light when seen from far away…and yes, it’s a geodreieck, old battered brittle plastic too :sweat_smile:

No advantage in condenser light source.

I purchased and experimented with Omega B enlarger condensers for NLP/digitalCamera “scans” and found little to be gained. Obviously any difference in contrast between condenser and diffuse lighting can be eliminated in Lightroom. I expected to find more detail, that is, more information with the collimated light. I did not, at least with a 24Mpx Sony Nex-7.

The condenser lighted images did show horrible dirt and scratches on the filmstrip that were completely absent in the diffuse lighted images.

Digitizer I am a bit confused by your description of condenser proper focus. I focussed the lamp in the aperture plane of the objective lens. This description of a slide projector shows what I did:

The condenser set L1 with focal length f1 was focussed such that 
1/f1 = 1/u1 + 1/v1

Screen Shot 2021-07-21 at 5.49.13 PM

Think of taking a portrait with undiffused flash light. Your subject will probably not like it.

This is how I sort of remember focusing the projectors for slideshows. It’s quite a while since I did it last time though. It was all about getting the most and most even light onto the screen. Maybe that focus needed to be changed to show the filaments…try it out

Hi Burkphoto,

Thanks for sharing your experience with the professional Kodak world. It’s striking to see that consumer digital cameras have become so good that they seem to render these professional machines obsolete. I don’t have any experience with professional software such as developed by Kodak, but was blown away by what NLP achieves with just a few mouse clicks. Considering the vast amount of film strips that most of us will have, time is everything when scanning.

My experience with scanning was far from professional: I started out in the early days of digital cameras with attempting to scan with a Nikon slide holder pointed at daylight, a lens, some macro tubes, and an early digital camera, but although the scans seemed okay-ish, it was very time consuming to get anywhere near good color and contrast. I then stumbled across a Minolta San Dual and Vuescan software that gave what looked like proper color out of the box. I then spend quite some long evenings scanning, but in the end gave up because it simply took too much time. In the end I sent everything in batches to Scancafe.com who had a good formula and were affordable. I got offered a Minolta Dimage Scan Multi ii for free at a garage sale that spent years in my closet. Now I’m back to film and tried it, but was again shocked by the time it takes to scan, but this time also by the much, much higher quality from a simple DSLR scan. So the circle is round, and I am back where I started, but mostly because I discovered NLP. Overall, if a scan takes longer than a few seconds to take a picture and a few mouse clicks to process the result, it’s unrealistic for me to consider re-processing my old films, simply because of time constraints. It seems that a smart DSLR setup (whatever shape that may have) plus NLP will enable sufficient short time per scan.

Regarding (tungsten) light sources: Elsewhere on these forums, I stumbled across Solux 4700K daylight sources, which seem to be quite popular, also in museums etcetera. Any thoughts on these?

Perhaps one of the advantages of going with an enlarger head as a light source (either collimated or diffused) is that it’s relatively easy to change the bulb into whatever seems best as a continuous spectrum bulb. You also mention color shift over time with a tungsten bulb, but doesn’t NLP take care of that when the white point is taken off the negative edge? (Not sure of that though)

Hi DavidS,

What you write seems to confirm what Digitizer was saying: A collimated light source has no advantages other than picking up more unwanted crud from the negative, and thus making it harder to get clean scans.

I’m not sure I understand why though, nor what optically exactly is going on, other than the empirical comparison with portrait shooting. Need to think about that some more…

A few days ago I picked up the old enlarger that I purchased for a few bucks. Now I need to find some time to set that up and play with that. Will report back what I find.

Cheers,

Arno

Last time I looked, Solux lamps are no longer available. They were extremely hot, too.

NLP (actually the eye dropper custom WB in LrC) does eliminate color shift. In optical analog systems, or when multiple tungsten devices are used, it’s a big issue.

I’m writing a full description of my setup with illustrations and will post next week.

Hi ArnoG,
Just to give you a bigger picture of what I am doing, I have NLP scanned about 10,000 of about 30,000 color negatives accumulated over a lifetime of photography.

About 20 years ago I purchased a Nikon Coolscan 4000ED for the same project but gave up because it was too slow. Recently I dusted it off and rescanned some NLP scanned negatives (with VueScan software). Wow! the Nikon has far greater control of color and far more information. So I purchased a non-working Coolscan to take apart and study. It has separate RGB and infrared LED illumination, condenser optics, a monochromatic line sensor, auto-focus for each exposure, a special 7 element lens, and Digital Ice for dust and scratches. So my scanning project is on hold while I try to duplicate the Nikon’s quality with NLP and my Sony cameras.

After my experiment with the Omega enlarger condensers I am convinced that condensers were not chosen for image quality. Instead they efficiently used the dim light from the early technology LEDs.

BTW, the biggest happy surprise so far has been the camera objective. I removed the Nikon lens from the broken Coolscan and use it now with the digital camera for NLP (replacing a Leitz Focotar enlarging lens). Now detail in my NLP scans is close that from the Nikon scanner-----with a diffuse light source.

I suspect that I could achieve the full detail of the Nikon scan with more resolution. The Nikon scanner lens only covers the 24 Mpx cropped sensor NEX-7, not full frame. On the brighter side, NEX-7 raw files are much smaller than those from the scanner.

@burkphoto: There’s still detailed data on solux.net on the 4700K (https://www.solux.net/cgi-bin/tlistore/infopages/4700k.html), but indeed so far I didn’t find a place to buy them except through alieexpress, which I’m reluctant to use…

So far my few experiments with DSLR scanning have been limited to B&W but I might go back and redo my old film stock, which is mostly color, so it’s good to know that WB can be taken care off easily.

Can’t wait to see your setup!

@davidS : this is great stuff! You realize that you might trigger a market for broken Nikon scanners this way? :wink:

Based on what we (I) learned so far, perhaps Nikon is using collimated light for IR scratch removal, and diffuse light for the actual scan?

I thought a bit more about the optics of collimated light showing up more unwanted crud and think it does make sense: If one imagines taking a picture of the emulsion side, i.e. with the emulsion side “up”, and a negative having a certain thickness below that, then with collimated light any scratches on the bottom will be clearly projected/shadowed on the top (emulsion) side. With a diffuse source, where light will enter not only perpendicular to the “bottom” but from all sides, these projections/shadows will be much less pronounced. One would still pickup scratches and dust on the emulsion side though, and I can’t yet reason whether these would be less pronounced with diffuse light.

At the same time, if one focuses on the emulsion side, and the emulsion side is “up”, then there should not be loss of sharpness due to the fact that the light is diffuse, in the same way that something is sharp when simply looking at it in diffuse light. Intuitively, I would think that scanning with the emulsion side up should always be better, since the light that contains the details of the image doesn’t have to travel through the film with all the scattering and loss of detail that could result from that, and instead can travel freely into the scanning lens. Does that make sense?

Finally, one could imagine that a limited depth of field would be ideal, so as to only have the thickness of the emulsion being sharp, but in practice this is probably not realistic due to most lenses not having optimal sharpness at their widest apertures.

All in all, taking into account experiences from others as written here, the Callier effect, and picking up as little scratches as possible, it seems to me that diffuse light should give a technically “best” scan, whereas collimated light could be used for “art effects” such as grittiness in B&W.

(?)

ArnoG, there already is an active market for broken Nikon scanners. This guy helped to create it with his lens testing.

Actually the Nikon scanner uses condenser illumination for both scratch/dust elimination and the actual scan. It does not use diffuse lighting at all. It has one monochromatic line sensor that moves down the filmstrip 4 times scanning the film 4 times. With each scan a different LED is lighted; red, green, blue, and IR. Your computer combines these separate scans into one RGB file.

I am doing my scans with the Sony NEX-7 camera, the Nikon scanner lens and diffuse light.

I hope this worked. I attached a PDF. See link below.

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